Alesis M20 User Manual

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ALESIS M20

ROFESSIONAL 20-BIT DIGITAL

RECORDER

OWNER’S MANUAL

FIRST EDITION VERSION 1.06

PPLIES TO OPERATING SOFTWARE VERSION 1.11

NCLUDES SOFTWARE VERSION 2.10 ADDENDUM

1999 ALESIS CORPORATION

ALESIS M20 REFERENCE MANUAL 1.06

TABLE OF CONTENTS

Important Safety Instructions and Compliance Notices ...................................... vii

Safety symbols used in this product................................................................................................ vii

Please follow these precautions when using this product: ............................................................ vii

Instructions de Sécurité Importantes.................................................................................................ix

Symboles utilisés dans ce produit......................................................................................................ix

Beim Benutzen dieses Produktes beachten Sie bitte die folgenden Sicherheitshinweise: ..............x

Information to the User for Class A Digital Device (FCC Part 15, Class A)................................... xi

CE Declaration of Conformity ...........................................................................................................xii

Overview, Setup, and Basics..............................................................................1

1.1 M20 Highlights .............................................................................................................................. 1

1.2 Unpacking and Inspection............................................................................................................2

1.3 AC Power Hookup........................................................................................................................ 2

1.4 Line Conditioners and Protectors................................................................................................. 3

1.5 About Audio Cables......................................................................................................................3

1.6 Basic Audio Hookup.....................................................................................................................4

1.7 Use the Right Tape......................................................................................................................... 4

1.8 Preparing the Tape Prior to Use...................................................................................................4

1.9 Eject Tape Properly........................................................................................................................4

1.10 Backup..........................................................................................................................................4

1.11 Operating Environment .............................................................................................................. 5

1.12 Avoid Electromagnetic Interference........................................................................................... 5

Control and Connector Basics ............................................................................1

2.1 About the Front Panel ...................................................................................................................1

2.2 About the Rear Panel.....................................................................................................................3

2.2a Punch Footswitch...........................................................................................................3

2.2b Locate/Play or LRC Remote Control Jack...................................................................3

2.2c Analog Inputs and Outputs...........................................................................................3

2.2d Time Code In and Out...................................................................................................3

2.2e Word Clock In and Out .................................................................................................3

2.2f ADAT Optical In and Out..............................................................................................3

2.2g Video In and Thru..........................................................................................................4

2.2h ADAT Sync In and Out................................................................................................. 4

2.2i MIDI In and Out ............................................................................................................. 4

2.2j RS-422 In (Sony 9-Pin).....................................................................................................4

2.2k Meter Bridge/Remote Panel Out..................................................................................4

2.2l Power............................................................................................................................... 4

Editing M20 Operating Parameters....................................................................1

3.1 The Keypad.................................................................................................................................... 1

3.1a 0 through 9 buttons........................................................................................................1

3.1b Up Arrow/Yes/Upper Case......................................................................................... 1

3.1c Down Arrow/No/Lower Case.....................................................................................1

3.1d Cursor Left.....................................................................................................................1

3.1e Cursor Right ...................................................................................................................1

3.1f Enter/Name.................................................................................................................... 2

3.1g Selecting Pages...............................................................................................................3

3.1h Selecting Page Parameters.............................................................................................3

3.1i Entering Parameter Values.............................................................................................3

3.2 The Edit Button.............................................................................................................................. 4

ALESIS M20 REFERENCE MANUAL 1.06 i

Table of Contents

3.3 Editing Conventions...................................................................................................................... 4

Tape Formatting...............................................................................................1

4.1 Sample Rate Selection....................................................................................................................2

4.1a Pull-up and Pull-down Sample Rate Selection ............................................................3

4.2 Word Length Selection..................................................................................................................3

4.3 Format a New Tape.......................................................................................................................4

4.4 Record Tracks While Formatting.................................................................................................. 4

4.5 Extend a Partially-Formatted Tape..............................................................................................5

4.6 End Formatting..............................................................................................................................5

4.7 Certify Tape Format ......................................................................................................................5

4.8 Reformatting: Caution!..................................................................................................................5

4.9 Lock Out Formatting (Safe Mode).................................................................................................6

4.10 Bulk Erasing.................................................................................................................................6

4.11 Recording a “Benchmark” Tape................................................................................................. 6

Track Record Enabling and Monitoring ..............................................................1

5.1 Track Basics ....................................................................................................................................1

5.2 Track Input Enables .......................................................................................................................2

5.3 Auto Input Switch ......................................................................................................................... 2

5.4 Record Enable................................................................................................................................2

5.5 Safety Mode (All Safe) ...................................................................................................................3

5.6 Monitor Inputs (All Input)............................................................................................................3

Digital/Analog Input Selection and Routing ........................................................1

6.1 Digital Source .................................................................................................................................1

6.2 Input Select .....................................................................................................................................1

6.3 Track Output Selection..................................................................................................................2

6.4 Input Signal Routing (Analog And Digital).................................................................................2

6.4a Analog Input Routing....................................................................................................3

6.4b Digital Input Routing.....................................................................................................4

6.4c Record-Enabling the Destination Tracks......................................................................5

6.5 Aux Routing (input and output) .................................................................................................. 6

Metering 1

7.1 Meter Mode Selection....................................................................................................................1

7.1a Clearing Peaks................................................................................................................1

7.2 Meter Setup....................................................................................................................................2

Transport Controls and Basic Recording.............................................................1

8.1 About the Tape Counter................................................................................................................ 1

8.2 Stop................................................................................................................................................. 1

8.3 Play ................................................................................................................................................. 2

8.3a Play Button and Sync Status..........................................................................................2

8.4 Jog/Shuttle Wheel and Search ......................................................................................................2

8.4a Jog Mode......................................................................................................................... 2

8.4b Shuttle Mode..................................................................................................................3

8.4c Search Button ..................................................................................................................3

8.4d Search Master .................................................................................................................4

8.5 Other Transport Buttons...............................................................................................................5

8.6 Record.............................................................................................................................................6

8.6a Punching Into Record ....................................................................................................6

8.6b Punching Out of Record................................................................................................6

8.6c Record Write-Protection................................................................................................ 7

8.6d Recording with a Footswitch........................................................................................7

8.7 Rehearse Mode................................................................................................................................7

8.8 Auto Record...................................................................................................................................8

ii ALESIS M20 REFERENCE MANUAL 1.06

Table of Contents

8.8a Setting Auto Record Punch Points................................................................................8

8.8b Enable Auto Record....................................................................................................... 9

8.8c Set Auto Punch Points “On the Fly”.............................................................................9

Autolocation ....................................................................................................1

9.1 Entering, Selecting, and Editing Location Points........................................................................1

9.1A Set Locate........................................................................................................................ 1

9.1B Copy Tape Location........................................................................................................ 1

9.2 Deferred Play and Record.............................................................................................................3

9.3 Play-After-Locate (Auto Play)......................................................................................................3

9.4 Loop Between Start and End Locate Points (Auto Return)........................................................3

9.4a Setting Loop Start and End Points ................................................................................4

9.5 Set Pre-Roll.....................................................................................................................................4

9.6 Set Post-Roll ...................................................................................................................................5

9.7 Footswitch-Controlled Location................................................................................................... 6

Varispeed ........................................................................................................1

SMPTE, Sync, and Offset Functions ...................................................................1

11.1 Clock Source.................................................................................................................................1

11.2 SMPTE Rate..................................................................................................................................2

11.3 Time Code Source ........................................................................................................................2

11.3a Internal...........................................................................................................................2

11.4 Chase Reference...........................................................................................................................3

11.5 Reference Counter ....................................................................................................................... 4

11.6 SMPTE Chase...............................................................................................................................4

11.6a Set SMPTE Offset Value (Page 1)................................................................................4

11.6b Set SMPTE Chase Mode (Page 2)................................................................................5

11.6c Set Flywheel Duration (Page 3)................................................................................... 5

11.6d Park Ahead (Page 4)....................................................................................................5

11.7 Internal Generator........................................................................................................................ 6

11.7a Generator Mode (Page 1) .............................................................................................6

11.7b Time Code Start Reference (Page 2) ........................................................................... 7

11.7c ABS/Start Offset (Page 3)............................................................................................7

11.7d User Bits (Page 4, or Page 3 if the Page 2 value is TC Track)...................................8

11.8 Tape Offset...................................................................................................................................8

11.9 Track Delay ................................................................................................................................10

MIDI Functions.................................................................................................1

12.1 MIDI Device (Page 1)................................................................................................................... 1

12.2 MMC Output (Page 2).................................................................................................................1

12.3 MTC Follow Gen (Page 3)...........................................................................................................1

12.4 Send Sysex Dump? (Page 4) ........................................................................................................1

12.5 Receive Sysex Dump? (Page 5)................................................................................................... 2

12.6 Send Software? (Page 6).............................................................................................................. 2

12.7 Load Software? (Page 7) ..............................................................................................................2

Utility Menu.....................................................................................................1

13.1 Digital Out (Page 1).....................................................................................................................1

13.2 Online Source (Page 2)................................................................................................................. 1

13.2a Online Button................................................................................................................ 1

13.2b Independent Slave Mode.............................................................................................2

13.3 Online Control (Page 3)...............................................................................................................2

13.4 One-Button Record (Page 4)........................................................................................................ 2

13.5 Input Monitor (Page 5)................................................................................................................ 2

13.6 Crossfade Time (Page 6)..............................................................................................................3

13.7 Time Code Output Level (Page 7)..............................................................................................3

ALESIS M20 REFERENCE MANUAL 1.06 iii

Table of Contents

13.8 Rewind/Fast Forward TC Output (Page 8) ...............................................................................3

13.9 Unthread Timeout (Page 9) .........................................................................................................3

13.10 Search Enable (Page 10)............................................................................................................. 4

13.11 Locate Before Play (Page 11).....................................................................................................4

13.12 Mute Until Lock (Page 12).........................................................................................................4

13.13 Dynamic Punch (Page 13).......................................................................................................... 4

13.14 Track Groups (Page 14)............................................................................................................. 4

13.15 Save Data to Tape? (Page 15)....................................................................................................4

13.16 Load Data from Tape? (Page 16) ..............................................................................................5

13.17 Tape Type (Page 17)...................................................................................................................5

13.18 ID Status (Page 18)..................................................................................................................... 5

13.19 User Bits (Page 19)..................................................................................................................... 5

13.20 Error Rate (Page 20)................................................................................................................... 6

13.21 Front Panel Software Version (Page 21)................................................................................... 6

13.22 Software Version (Page 22) .......................................................................................................6

The LRC Remote Control....................................................................................1

Tutorials and Applications ................................................................................1

TUTORIAL 1: Multiple M20 Operation..............................................................................................1

Overview................................................................................................................................. 1

Synchronizing Machines ........................................................................................................ 1

Automatic ID Renumbering...................................................................................................1

Master/Slave Interaction........................................................................................................ 2

Achieving Lock .......................................................................................................................2

Independent Slave Mode........................................................................................................ 2

Formatting Multiple Tapes.................................................................................................................. 3

Master Format Enabled, Complete Format ..........................................................................3

Master Format Enabled, Format Extend ...............................................................................3

Master Format Disabled......................................................................................................... 4

Master Format Disabled, Format Extend..............................................................................4

TUTORIAL 2: Making Digital Backups..............................................................................................5

Dealing with Damaged Tape.................................................................................................6

Making a 16-bit copy from a 20-bit master...........................................................................6

TUTORIAL 3: Recording Digital Audio from Other Sources ...........................................................7

Digital Clock Considerations.................................................................................................7

TUTORIAL 4: Combining M20s and ADATs ....................................................................................8

M20 Transport Speed ............................................................................................................. 8

Sample rate vs. Pitch Control.................................................................................................8

Input Monitoring .................................................................................................................... 8

Polarity Differences ................................................................................................................ 9

TUTORIAL 5: Setting up Inputs........................................................................................................10

TUTORIAL 6: Updating M20 Software............................................................................................11

TUTORIAL 7: Using the M20 with Unbalanced Inputs and Outputs............................................12

M20 SMPTE Synchronization Overview ..............................................................1

16.1 Synchronization Basics.................................................................................................................1

Master or Slave? ......................................................................................................................1

Digital Timing Requirements.................................................................................................1

16.2 The One Clock Principle..............................................................................................................2

16.2a House Sync ...................................................................................................................2

16.2b “Genlocked” Time Code...............................................................................................2

16.3 Reference Counters vs. Clock Sources....................................................................................... 3

16.3a Location Reference........................................................................................................3

16.3b Reference Clock............................................................................................................. 3

16.3 Offsets in the M20........................................................................................................................5

iv ALESIS M20 REFERENCE MANUAL 1.06

Table of Contents

16.3a SMPTE Chase Offset.................................................................................................... 5

16.3b Internal Generator ABS Offset..................................................................................... 6

16.3c Tape Offset.................................................................................................................... 6

16.4 SMPTE Time Code Rates and Types ...........................................................................................7

16.4a Drop Frame....................................................................................................................7

16.4b Auto-detection of SMPTE Rates .................................................................................. 7

16.4c VITC (Vertical Interval Time Code) ............................................................................8

16.4d MTC (MIDI Time Code) ...............................................................................................8

Time Code Tutorial...........................................................................................1

17.1 Generating Time Code onto a VCR............................................................................................ 1

17.2 Synchronizing Without a T/C Track...........................................................................................2

17.3 Recording a Time Code Track....................................................................................................3

17.3a Recording SMPTE from ABS Time..............................................................................3

Maintenance and Troubleshooting.....................................................................5

18.1 ADAT Head Cleaning................................................................................................................. 5

18.1a Head Cleaning Cassettes (optional)............................................................................6

18.1b Manual Head and Tape Path Cleaning ......................................................................6

18.2 ADAT Head Life..........................................................................................................................7

18.2a Head Alignment...........................................................................................................7

18.3 Tape Maintenance: Safe Tape ..................................................................................................... 8

18.3a Tape Wear..................................................................................................................... 8

18.3b Care of ADAT Tapes ................................................................................................... 8

18.4 Maintenance/Service...................................................................................................................9

18.4a Exterior Cleaning.......................................................................................................... 9

18.4b Maintenance ................................................................................................................. 9

18.4d Obtaining Repair Service...........................................................................................10

M20 Hidden Functions ......................................................................................1

Power-On Button Combinations.........................................................................................................1

Miscellaneous Button Combinations .................................................................................................. 1

Advanced Functions............................................................................................................................. 3

Using The M20 Data Section Of Tape .................................................................1

General data section convention on the M20.....................................................................................1

M20 Locate Points and SMPTE Offsets .............................................................................................. 1

BRC ⇔ M20 Song Start / SMPTE Start Offset and Locate Point Map.............................................1

BRC ⇔ M20 Parameter Map...............................................................................................................2

M20 Transport & System Error Messages...........................................................1

M20 Major Feature Update: Version 2................................................................1

RS-422 (Sony 9-pin) slave operation.................................................................................................... 1

RS-422 Track Arm: On/Off.................................................................................................... 1

RS-422 Mapping: 1-2, OddEvn, (Local).................................................................................1

ID 1 offline with the CADI remote......................................................................................................2

CADI Tape and Reference Counter indications when ID 1 is offline...............................................2

Storing locate points when ID 1 is offline ...........................................................................................2

Tape TC detection in fast wind modes...............................................................................................3

Tape TC in the Tape Counter ..............................................................................................................4

Fixed mode time code generation: “TC Start Ref: Fixed”................................................................. 4

Digital Scrub: “Dig Scan: On/Off, nn dB”..........................................................................................5

I/O Card as the digital source.............................................................................................................5

SMPTE Chase with the Stop button.................................................................................................... 5

Tape TC updating when in Input mode............................................................................................. 5

Vari-Speed and Pull-Up/Down ..........................................................................................................5

ALESIS M20 REFERENCE MANUAL 1.06 v

Table of Contents

MIDI Thru.............................................................................................................................................6

New Utility page order........................................................................................................................6

CADI display changes..........................................................................................................................6

Cassette Auto-Inject ............................................................................................................................. 6

Deck Standby Mode............................................................................................................................. 7

Auto-Park After Formatting................................................................................................................7

Deferred Eject .......................................................................................................................................7

New RS-422 Device ID.........................................................................................................................7

Improved SMPTE Clock Source Recognition.....................................................................................7

Sample Rate Change During Play/Record .........................................................................................7

vi ALESIS M20 REFERENCE MANUAL 1.06

IMPORTANT SAFETY

INSTRUCTIONS AND COMPLIANCE

NOTICES

SAFETY SYMBOLS USED IN THIS PRODUCT

This symbol alerts the user that there are important operating and

maintenance instructions in the literature accompanying this unit.

This symbol warns the user of uninsulated voltage within the

unit that can cause dangerous electric shocks.

PLEASE FOLLOW THESE PRECAUTIONS WHEN USING THIS

PRODUCT

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a damp cloth.

7. Do not block any of the ventilation openings. Install in accordance with the

8. Do not install near any heat sources such as radiators, heat registers, stoves, or

1. Read these instructions.

Do not spray any liquid cleaner onto the faceplate, as this may damage the front panel

controls or cause a dangerous condition.

manufacturer's instructions.

other apparatus (including amplifiers) that produce heat.

(more on next page)

ALESIS M20 REFERENCE MANUAL 1.06 vii

Safety Notices

10. Protect the power cord from being walked on or pinched particularly at plugs,

11. Use only attachments/accessories specified by the manufacturer.

12. Use only with a cart, stand, tripod, bracket, rack, or table specified by the

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding-type plug has two blades and a third grounding prong. The wide blade or the third prong is provided for your safety. When the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

convenience receptacles, and the point where they exit from the apparatus.

manufacturer, or sold with the apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.

Alesis recommends the use of standard 19” racks designed for use with professional audio or music equipment, and the use of rear rack rail supports or sliders. In any installation, make sure that injury or damage will not result from cables pulling on the apparatus and its mounting.

13. Unplug this apparatus during lightning storms or when unused for long periods of time.

14. Refer all servicing to qualified service personnel. Servicing is

required when the apparatus has been damaged in any way, such as when the power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.

15. This unit produces heat when operated normally. If this unit is installed in a rack, make sure that there is proper ventilation when operated. Do not operate in an enclosed rack with closed front and back doors. If there are other units in the rack that generate a large amount of heat, spread them apart. Do not sandwich this product between two large heat-producing units.

16. This product, in combination with an amplifier and headphones or speakers, may be capable of producing sound levels that could cause permanent hearing loss. Do not operate for a long period of time at a high volume level or at a level that is uncomfortable. If you experience any hearing loss or ringing in the ears, you should consult an audiologist.

viii ALESIS M20 REFERENCE MANUAL 1.06

INSTRUCTIONS DE SÉCURITÉ IMPORTANTES

SYMBOLES UTILISÉS DANS CE PRODUIT

Ce symbole alèrte l’utilisateur qu’il existe des instructions de fonctionnement et de maintenance dans la documentation jointe avec ce produit.

Ce symbole avertit l’utilisateur de la prèsence d’une tension non isolèe à l’intèrieur de l’appareil pouvant engendrer des chocs èlectriques.

Veuillez suivre ces prècautions lors de l’utilisation de l’appareil:

1. Lisez ces instructions.

2. Gardez ces instructions.

3. Tenez compte de tous les avertissements.

4. Suivez toutes les instructions.

5. N’utilisez pas cet allareil à proximitè de l’eau.

Safety Notices

6. Ne nettoyez qu’avec un chiffon humide. Ne pas vaporiser de liquide nettoyant sur l’appareil, cela pourrait abîmer les contrôles de la face avant ou engendrer des conditions dangeureuses.

7. Installez selon les recommandations du constructeur.

8. Ne pas installer à proximilè de sources de chaleur comme radiateurs, cuisinière ou autre appareils (don’t les amplificateurs) produisant de la chaleur.

9. Ne pas enlever la prise de terre du cordon secteur. Une prise murale avec terre deux broches et une troisièrme relièe à la terre. Cette dernière est prèsente pour votre sècuritè. Si le cordon secteur ne rentre pas dans la prise de courant, demandez à un èlectricien qualifiè de remplacer la prise.

10. Evitez de marcher sur le cordon secteur ou de le pincer, en particulier au niveau de la prise, et aux endroits où il sor de l’appareil.

11. N’utilisez que des accessoires spècifiès par le constructeur.

12. N’utilisez qu’avec un stand, rack ou table conçus pour l’utilisation d’audio professionnel ou instruments de musique. Dans toute installation, veillez de ne rien endommager à cause de câbles qui tirent sur des appareils et leur support.

13. Dèbranchez l’appareil lors d’un orage ou lorsqu’il n’est pas utilisè pendant longtemps.

14. Faites rèparer par un personnel qualifiè. Une rèparation est nècessaire lorsque l’appareil a ètè endommagè de quelque sorte que ce soit, par exemple losrque le cordon secteur ou la prise sont endommagès, si du liquide a coulè ou des objets se sont introduits dans l’appareil, si celui-ci a ètè exposè à la pluie ou à l’humiditè, ne fonctionne pas normalement ou est tombè.

15. Cet appareil produit de la chaleur en fonctionnement normal. Si cet appareil est utilisè dans un rack, veillez à sa bonne ventilation lors de son utilisation. Ne pas faire fonctionner dans un rack fermè. S’il y a d’autres appareils dans le rack gènèrant beaucoup de chaleur, èloignez les. Ne pas intercaler cet appareil entre deux appareils produisant beaucoup de chaleur.

ALESIS M20 REFERENCE MANUAL 1.06 ix

Safety Notices

16. Ce produit, utilisè avec un amplificateur et un casque ou des enceintes, est capable de produite des niveaux sonores pouvant engendrer une perte permanente de l’ouïe. Ne l’utilisez pas pendant longtemps à un niveau sonore èlevè ou à un niveau non confortable. Si vous remarquez une perte de l’ouïe ou un bourdonnement dans les oreilles, consultez un spècialiste.

BEIM BENUTZEN DIESES PRODUKTES BEACHTEN SIE

BITTE DIE FOLGENDEN SICHERHEITSHINWEISE:

1. Lesen Sie die Hinweise.

2. Halten Sie sich an die Anleitung.

3. Beachten Sie alle Warnungen.

4. Beachten Sie alle Hinweise.

5. Bringen Sie das Gerät nie mit Wasser in Berührung.

6. Verwenden Sie zur Reinigung nur ein weiches Tuch. Sprühen Sie keine flüssiger Reiniger auf die Oberfläche, dies könnte zur Beschädigung der Vorderseite führen und auch weitere Schäden verursachen.

7. Halten Sie sich beim Aufbau des Gerätes an die Angaben des Herstellers.

8. Stellen Sie das Gerät nich in der Nähe von Heizkörpern, Heizungsklappen oder anderen Wärmequellen (einschließlich Verstärkern) auf.

9. Verlegen Sie das Netzkabel des Gerätes niemals so, daß man darüber stolpern kann oder daß es gequetscht wird.

10. Benutzen Sie nur das vom Hersteller empfohlene Zubehör.

11. Verwenden Sie ausschließlich Wagen, Ständer, Racks oder Tische, die speziell für professionelle Audio- und Musikinstrumente geeignet sind. Achten Sie immer darauf, daß die jeweiligen Geräte sicher installiert sind, um Schäden und Verletzungen zu vermeiden. Wenn Sie einen Rollwagen benutzen, achten Sie darauf, das dieser nicht umkippt, um Verletzungen auszuschließen.

12. Ziehen Sie während eines Gewitters oder wenn Sie das Gerät über einen längeren Zeitraum nicht benutzen den Netzstecher aus der Steckdose.

13. Die Wartung sollte nur durch qualifiziertes Fachpersonal erfolgen. Die Wartung wird notwendig, wenn das Gerät beschädigt wurde oder aber das Stromkabel oder der Stecker, Gegenstände oder Flüssigkeit in das Gerät gelangt sind, das Gerät dem Regen oder Feuchtigkeit ausgesetzt war und deshalb nicht mehr normal arbeitet oder heruntergefallen ist.

14. Bei normalem Betrieb des Gerätes kommt es zu Wärmeentwicklungen. Wenn Sie das Gerät in einem Rack eingebaut haben, sollte während des Betriebes die Zufuhr von Kühlluft stets gewährleitstet sein. Arbeiten Sie nie bei geschlossenem Rack. Bei mehreren Rackgeräten sollten diese mit einem geringen abstand voneinander eingebaut werden. Stapeln Sie dieses Gerät nicht zwischen Geräten mit hoher Wärmeentwicklung.

15. Dieses Produkt kann in Verbindung mit einem Verstärker und Kopfhörern oder Lautsprechern Lautstärkepegel erzeugen, die anhaltende Gehörschäden verursachen. Betreiben Sie es nicht über längere Zeit mit hoher Lautstärke oder einem Pegel, der Ihnen unangenehm is. Wenn Sie ein Nachlassen des Gehörs oder ein Klingeln in den Ohren feststellen, sollten Sie einen Ohrenarzt aufsuchen.

x ALESIS M20 REFERENCE MANUAL 1.06

Safety Notices

INFORMATION TO THE USER FOR CLASS A DIGITAL DEVICE (FCC PART 15, CLASS A)

This equipment has been tested and found to comply with the limits for a class A digital device pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause interference to radio communications. Operation of this equipment in a residential area is likely to cause interference in which case the user will be required to correct the interference at his own expense.

The user is cautioned that changes and modifications made to the equipment without the approval of manufacturer could void the user’s authority to operate this equipment.

Use only shielded and grounded cables with this equipment to ensure compliance with FCC Rules.

INDUSTRY CANADA (DIGITAL APPARATUS) I

NTERFERENCE-CAUSING EQUIPMENT STANDARD

ICES-003 ISSUE 2

This Class A digital apparatus meets all requirements of the Canadian Interference-

Causing Equipment Regulations.

ALESIS M20 REFERENCE MANUAL 1.06 xi

Safety Notices

CE DECLARATION OF CONFORMITY

Manufacturer’s Name: Alesis Corporation

Manufacturer’s Address: 1633 26th Street

Santa Monica, CA 90404 USA

declares, that the product:

Product Name: M20 Product Type: Modular Digital Multitrack Recorder

conforms to the following Standards:

Application of Council Directive: 89/336/EEC; 73/23/EEC

Safety: EN 60 065

(1993) First Edition, Amendment No.1 (1994)

EMC: EN 55022:1988 Class A

IEC 801-2:1991 2nd Edition, 4kV direct, 8kV air IEC 801-3:1984 2; 3V/m 150MHz-1GHz IEC 801-4:1988 1st Edition 2; 1kV, 0.5kV

All tests were performed with fully-shielded cabling.

European Contact: Sound Technology

17 Letchworth Point, Lechworth, Hertfordshire, SG6 1ND, England. Phone: +44.1462.480000 Fax: +44.1462.480800

April, 1998

xii ALESIS M20 REFERENCE MANUAL 1.06

OVERVIEW, SETUP, AND

The Alesis M20 is an 8-track digital tape recorder that records on S-VHS videotape cassettes. It is compatible with the ADAT format used with several other digital recorders (Alesis ADAT, ADAT XT, LX20, and XT20; Studer V-Eight; Fostex RD-8 and CX-8; and Panasonic MDA-1).

1.1 M20 HIGHLIGHTS

• Direct-drive full-servo S-VHS transport, designed for continuous shuttling and heavy- duty professional use

• Two available bit resolutions: 16-bit standard ADAT Type I, and 20-bit ADAT Type II

• 24-bit A/D and D/A converters

• +4 dBu balanced XLR and ELCO (multipin) connectors

• Selectable 16-bit dithered output for transfer to 16-bit systems

• Jog/shuttle wheel for fast navigation

• Analog Aux track for superb scrub and jog monitoring

• ADAT , SMPTE, video and word clock synchronization capabilities

• Dedicated SMPTE time code track

• Optional EC-1 8 channel AES/EBU digital audio interface

• Two custom vacuum fluorescent displays

• Extensive error reporting capability

• Optional CADI remote control

• Optional RMD remote meter display

CHAPTER 1

BASICS

ALESIS M20 REFERENCE MANUAL 1.06 1-1

Overview, Setup and Basics, Chapter 1

1.2 UNPACKING AND INSPECTION

Please retain the M20’s shipping carton, which is designed to protect the unit during shipping, in the unlikely event that you need to return the M20 for servicing. Some carriers have restrictions on shipping electronic equipment without the original packing.

The shipping carton contains:

§ M20 with the same serial number shown on shipping carton

§ Power Cable

§ Optical Cable

§ M20 LRC (remote control unit)

§ This instruction manual

§ Blank S-VHS ST-120 cassette

§ Alesis warranty card

In order to be advised of future updates, please register your purchase immediately by filling out the warranty card and mailing it back to Alesis.

1.3 AC POWER HOOKUP

1 Make sure the M20 is turned off. It’s good practice not to turn on the M20 until all other

cables are hooked up.

2 Before plugging in to AC power, note that the M20’s IEC-spec AC cord (do not

substitute any other AC cord) must feed a 3-pin outlet, where the third, round pin connects to ground. The ground connection is an important safety feature designed to keep the chassis of electronic devices at ground potential. Unfortunately, the presence of a third ground pin does not always indicate a properly grounded outlet; check this with an AC line tester. If the outlet is not grounded, consult with a licensed electrician.

3 Plug the power cord’s female end into the M20’s power input socket, and the male

(plug) end into any AC power source from 90 to 250 volts, 50 or 60 Hz.

Your M20 includes the correct power cord for your country or local area. When using an M20 abroad , use only the following alternative power cords approved for use with ADAT:

• For 90-120 VAC 50/60 Hz operation in the US, Canada and/or Japan, use Alesis UL/CSA power cord #7-41-0001.

• For 240 VAC 50 Hz operation in England, use Alesis UK power cord #7-41-0004.

• For 220 VAC 50 Hz operation in Europe and Scandinavia, use Alesis EU power

cord #7-41-0002.

• For 240 VAC 50 Hz operation in Australia, use Alesis AS power cord #7-41-0003.

1-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 1, Overview, Setup and Basics

Alesis cannot be responsible for problems caused by using the M20 or any

associated equipment with improper AC wiring.

1.4 LINE CONDITIONERS AND PROTECTORS

Although the M20 tolerates typical voltage variations, the AC line voltage may contain spikes or transients that can possibly stress your gear and, over time, cause a failure. There are three main ways to protect against this, listed in ascending order of cost and complexity:

• Line spike/surge protectors. Relatively inexpensive, these help protect against strong surges and spikes (they usually need to be replaced after enduring an extremely strong spike).

• Line filters. These generally combine spike/surge protection with filters that remove some line noise (dimmer hash, transients from other appliances, etc.).

• Uninterruptible power supply (UPS). This is the best option. A UPS provides power even if the AC power line fails completely. Intended for computer applications, a UPS allows an orderly shutdown in the event of a power outage. Furthermore, the isolation it provides from the power line minimizes all forms of interference ó spikes, noise, etc.

1.5 ABOUT AUDIO CABLES

The connections between the M20 and your studio are your music’s lifeline. Use only high quality, low-capacitance, shielded cables with a stranded (not solid) internal conductor and low-resistance shield. Although quality cables cost more, they make a difference. When routing cables:

• Do not bundle audio cables with AC power cords.

• Avoid running audio cables near sources of electromagnetic interference such as

transformers, monitors, computers, etc.

• Do not place cables where they can be stepped on. Stepping on a cable may not cause immediate damage, but it can compress the insulation between the center conductor and shield (degrading performance) or reduce the cable’s reliability.

• Avoid twisting the cable or making sharp, right angle turns.

• Never unplug a cable by pulling on the wire itself. Always unplug by firmly grasping

the plug’s body, and pulling directly outward.

• Although Alesis does not endorse any specific product, chemicals such as Tweek and Cramolin, when applied to electrical connectors, are claimed to improve the electrical contact between connectors.

ALESIS M20 REFERENCE MANUAL 1.06 1-3

Overview, Setup and Basics, Chapter 1

1.6 BASIC AUDIO HOOKUP

When connecting audio cables and/or turning power on and off, turn off all devices in your system and turn down your monitor system’s volume controls.

The M20 provides 10 pairs of XLR connectors (8 pairs for audio in/out, 1 pair for the auxiliary analog channel, and 1 pair above for SMPTE time code). The nine sets of audio XLRs connect to your mixer’s tape or line inputs and outputs. An additional multipin ELCO connector , wired in parallel with the 8 XLR audio pairs, can connect to a “snake” that goes to your mixer. Several manufacturers make ADAT/M20-specific cables that break out the ELCO connector into individual ins and outs.

1.7 USE THE RIGHT TAPE

Use only premium quality, name brand S-VHS cassettes such as Quantegy 489 DM Digital Mastering Audio Tape, or Alesis ADAT Mastering Audio Cassettes. Other acceptable brands

include Maxell XR-S Black, JVC XZ, Sony DASV, BASF Digital Master 938, Apogee AA-40, HHB ADAT45, and TDK SP Super Pro. The cassette shell, hubs, rollers and tape guides in SVHS cassettes are precision devices that properly handle and protect the tape within them.

Caution: Do not use VHS cassettes. While they may appear to function properly at

first, their less-than-premium formulation will decrease the reliability of your recording. They may also shed oxide and leave behind a coating of dirt that will interfere with future recordings, even if you switch back to premium quality tape. Defective tape may even clog the head, requiring service. Trust your work only to premium quality S-VHS tape.

1.8 PREPARING THE TAPE PRIOR TO USE

Fast forward and rewind all new tapes at least once from end to end before attempting to format and record on them. This important step “unpacks” the tape properly, and leads to far more reliable operation (this is also recommended practice for DAT tapes).

1.9 EJECT TAPE PROPERLY

After a session, eject the tape and put it in a protective case. Do not:

• Leave the tape in the M20 when power is off.

• Leave the tape halfway ejected in the well. Always remove completely after ejection.

• Eject in the middle of recorded material. Malfunctions that could possibly damage the

tape are statistically most likely to occur when inserting or ejecting a tape, so always eject where nothing is recorded.

1.10 BACKUP

Accidents can happen ó so, like computer floppy disks and hard disks, back up your M20 tapes to another M20 or ADAT using the fiber optic digital connector (see Tutorial 2 for step-by-step instructions on backing up M20 tapes).

1-4 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 1, Overview, Setup and Basics

1.11 OPERATING ENVIRONMENT

Mount the M20 in an equipment rack (requires 4 rack spaces) or place it on a table or shelf. Alesis advises against tilting the recorder; keep it horizontal. Also remember that heat shortens the life of electronic equipment.

Please observe the following:

• The M20 is designed to perform properly over a range of ambient temperatures from 10° C to +40° C (50° F to 104° F), in up to 80% non-condensing humidity. These are not absolute limits, but Alesis cannot guarantee that the M20 will meet its published specs or remain reliable if operated outside of these ranges.

• Always allow adequate ventilation behind the M20. Do not seal any enclosure that holds the M20. It is not necessary to leave an empty rack space above or below the M20.

• You will need to remove the screw-on feet from the bottom of the M20 if any equipment will be mounted directly below it.

1.12 AVOID ELECTROMAGNETIC INTERFERENCE

Like all tape machines, the M20 uses magnetic tape that can be sensitive to electromagnetic interference. Generally this is not a problem, but avoid mounting the M20 next to devices that generate strong magnetic fields such as power amplifiers, monitors and video display devices, speakers, etc., and always treat your tapes with care. In particular, avoid excess heat, cold, and humidity.

ALESIS M20 REFERENCE MANUAL 1.06 1-5

Overview, Setup and Basics, Chapter 1

Figure 1 (M20 Front Panel)

1-6 ALESIS M20 REFERENCE MANUAL 1.06

CONTROL AND CONNECTOR

2.1 ABOUT THE FRONT PANEL

Referring to Fig. 1, the front panel includes:

• S-VHS cassette door and Eject button

• Main vacuum fluorescent display (toward the center) with two sets of 10-character 7-

segment readouts. The left readout shows the current tape location. The right readout shows information such as incoming SMPTE time, locate address, current offset, etc. A 24-character alphanumeric display above the 7-segment display shows edit location points, pre/post-roll times, pitch value, and various messages.

• 9 function buttons (below the main display)

• 5 transport buttons

• 4 locate-related buttons

CHAPTER 2

BASICS

• Rehearse button

• Jog/shuttle wheel and search button

• 15-button numeric keypad for data entry

• 15 editing switches

• Secondary vacuum fluorescent display with VU meters for the 8 audio channels and

auxiliary track, the time code track signal, error lights, track input and record lights, and input selection and routing indicators.

• 22 track enable and track record buttons

• 6 routing, source selection, and metering buttons

• Online/offline button

• Recessed power switch

ALESIS M20 REFERENCE MANUAL 1.06 2-1

Control and Connector Basics, Chapter 2

Figure 2 (M20 Rear Panel with optional EC-1 AES/EBU Card)

2-2 ALESIS M20 REFERENCE MANUAL 1.06

2.2 ABOUT THE REAR PANEL

Referring to Fig. 2, the rear panel includes:

2.2A PUNCH FOOTSWITCH

This allows foot-controlled punch in and out. Use a momentary footswitch, either normallyopen or normally-closed (the M20 senses the type on power-up and calibrates itself).

2.2B LOCATE/PLAY OR LRC REMOTE CONTROL JACK

This 1/4” jack accepts a momentary footswitch (normally closed or open) to allow footcontrolled location functions. It also accepts the LRC remote control (see Chapter 14) for remote access of transport functions.

Note: If using a normally open footswitch, the footswitch and LRC remote control can be

interchanged, or used simultaneously with a Y-cord, without restarting (powering down and powering up) the M20. However, if using a normally closed footswitch, the M20 unit should be restarted after switching from footswitch to remote control and vice-versa.

Chapter 2, Control and Connector Basics

2.2C ANALOG INPUTS AND OUTPUTS

18 XLR connectors carry the +4 dBu balanced analog inputs and outputs. There are 9 audio input and output channels (channels 1 through 8 plus Aux). Channels 1 through 8 inputs and outputs are also accessible through a multi-pin ELCO connector, which is wired in parallel with the XLR inputs and outputs. All XLR connectors are wired with pin 2 “hot,” in accordance with IEC standards.

2.2D TIME CODE IN AND OUT

The time code input and output use balanced XLR connectors for use with SMPTE/EBU standard time code systems. Time code input allows the M20 to be slaved to an external device; time code output provides timing reference to an external device.

2.2E WORD CLOCK IN AND OUT

These are BNC connector, TTL-level word clock inputs and outputs. A master word clock signal, which the M20 can provide, allows synchronizing the audio data stream for all digital audio devices in a system. If a master word clock signal already exists, the M20 can sync to it.

2.2F ADAT OPTICAL IN AND OUT

The optical input and output are an industry-standard digital audio interface, pioneered by Alesis, that carries 8 digital audio channels (with up to 24 bits of resolution) on a single fiber optic cable. The standard cable is a 1mm diameter plastic fiber with Toslink connectors. One 1-meter cable is provided with the M20; additional cables of different lengths are available from your dealer. Applications include digitally dubbing from one deck to another, interfacing with hard disk recording systems and synthesizers, and feeding translators that change the ADAT optical format to other formats.

ALESIS M20 REFERENCE MANUAL 1.06 2-3

Control and Connector Basics, Chapter 2

2.2G VIDEO IN AND THRU

The BNC connector video input (with 75 ohm termination switch) accepts composite video as well as black burst video inputs.

2.2H ADAT SYNC IN AND OUT

These 9-pin D connectors synchronize multiple ADATs together to single-sample accuracy. Computer interface cards with ADAT sync, such as the Alesis ADAT-PCR, allow transferring ADAT data to and from a computer for editing with single-sample accuracy. Interface cards without ADAT sync allow transferring ADAT data with 1/4 frame accuracy via MIDI Time Code.

2.2I MIDI IN AND OUT

These 5-pin DIN connectors can output and/or receive MIDI Machine Control commands, save and load sysex dumps defining the M20 status, allow for software updates via MIDI sysex files, and output MTC (MIDI Time Code) when selected.

2.2J RS-422 IN (SONY 9-PIN)

This 9-pin D connector connects to a video editor or other controller that supports the Sony 9-pin protocol. This feature will not be operational until M20 Version 2.0 software becomes available.

2.2K METER BRIDGE/REMOTE PANEL OUT

This RJ-45 connector connects to an optional remote controller like the Alesis CADI remote, and/or RMD meter bridge.

2.2L POWER

The IEC-standard, grounded AC input plug accepts AC voltages from 90 to 250 volts, eliminating the need for transformers or voltage switches.

2-4 ALESIS M20 REFERENCE MANUAL 1.06

EDITING M20 OPERATING

3.1 THE KEYPAD

The keypad block contains switches for editing the various parameters that control the M20’s features.

3.1A 0 THROUGH 9 BUTTONS

Use the 10 numeric keys to enter number parameter values and letters for names. When editing a parameter value, pressing a key enters its associated number. When editing a name, pressing a key cycles through the letters indicated on the keycap (e.g., pressing 7 repeatedly cycles through 7, s, t, u, v, 7, s, t…etc.).

3.1B UP ARROW/YES/UPPER CASE

This key:

CHAPTER 3

PARAMETERS

• Increments parameter values, as well as scrolls up through a list of parameter values. Holding this button for 2 or more seconds increases the speed at which the values increment. After 7 seconds, this speed increases again.

• Enters “Yes” in response to Yes/No queries.

• In a sign (polarity) field, selects the positive (+) sign.

• In a name field, changes lower case letters to UPPER CASE.

3.1C DOWN ARROW/NO/LOWER CASE

This key:

• Decrements parameter values, as well as scrolls down through a list of parameter values. Holding this button for 2 or more seconds increases the speed at which the values decrement. After 7 seconds, this speed increases again.

• Enters “No” in response to Yes/No queries.

• In a sign (polarity) field, selects the negative (-) sign.

• In a name field, changes UPPER CASE letters to lower case.

3.1D CURSOR LEFT

When editing, this key positions the cursor (a single underline character, showing that a parameter is ready for editing) under the next field to the left. (Note: It will not move across page boundaries.)

3.1E CURSOR RIGHT

When editing, this key positions the cursor (a single underline character) under the next field to the right. (Note: It will not move across page boundaries.)

ALESIS M20 REFERENCE MANUAL 1.06 3-1

Editing M20 Parameters, Chapter 3

3.1F ENTER/NAME

This key has two main uses:

• Speed up numeric entry by eliminating the need for “leading zeroes.” For example, the varispeed setting is a 3-digit value. Instead of having to key in something like 0 - 0 - 9, you can simply key in 9, then press Enter.

• Edit location point names. When the locate time is the currently selected field, pressing the Enter/Name button positions the cursor at the first character of the name. The cursor buttons now select individual characters within the name field or other displayed fields; use the keypad buttons to change the character. For upper case, use the Up Arrow. For lower case, use the Down Arrow.

To exit the name field, press the Enter/Name button again.

Using the default name list instead of entering letters individually: An additional

name editing option is available. Holding down the Name button while using the Up/Down buttons scrolls through a default set of 16 generic names (e.g., Verse 1, Chorus, Bridge, etc.). This list may be customized for your working style.

To customize the default set of names:

1 Select the default name to be changed. 2 Edit it. 3 To store the new name in the default name list, hold the Enter/Name button and press

the Record button.

3-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 3, Editing M20 Parameters

3.1G SELECTING PAGES

Most buttons have at least one associated display page, which contains one or more parameters. If there are multiple pages, the main display’s left side shows the current page number; repeatedly pressing the associated button cycles through the pages.

Shortcut: To access a particular page directly, hold the associated button and use the keypad to enter the desired single-digit page number.

Functions with double-digit page numbers (e.g., the Utility function) have a different access procedure. Hold the current function button and press the 2 digits within 3 seconds of each other. To select a single digit page number (1 through 9), press and hold the current function button and either:

• Enter 0, then the digit; or

• Press the single digit, then the Enter button. (Note: If the Enter button is not pressed

within 3 seconds, the display reverts to its previous state.)

3.1H SELECTING PAGE PARAMETERS

To select the desired parameter for editing in multi-parameter pages, position the cursor with the Left or Right Cursor button under the parameter value’s rightmost digit.

3.1I ENTERING PARAMETER VALUES

Entering complete values: Use the numeric keypad and enter the most significant digit first. Enter all of a field’s digits to complete the entry. The cursor automatically advances through the fields.

Increment/decrement a value by one: Use the keypad’s Up and Down buttons. Holding the Up or Down button for more than 2 seconds increments (or decrements) the value continuously. The value above the cursor will be changed. If the value goes beyond a boundary (for example, increasing from 59 seconds to 0), the next field will be calculated automatically (in this example, the minute field will be automatically increased).

ALESIS M20 REFERENCE MANUAL 1.06 3-3

Editing M20 Parameters, Chapter 3

3.2 THE EDIT BUTTON

The Edit button toggles the M20 in and out of Edit Mode. Enabling Edit mode (button lit) allows editing parameter values for the functions grouped with the Edit button: Track Delay, Tape Offset, SMPTE Chase, Internal Gen, Format, Pre-Roll, Post-Roll, Auto Return, and Auto Record. While Edit is On, only the currently selected function’s switch will light. However, the M20 retains the current on/off status of all switches, and these become visible after exiting Edit mode.

Note: Don’t be confused! Editing a function does not turn it on. For example, while

editing the Post Roll value the Post Roll switch will be lit, but if the light goes out when you leave Edit mode, Post Roll is not yet active.

If the Edit LED is not lit, pressing the various switches toggles these functions on and off. Example: If you’ve used the Edit button to edit the amount of Tape Offset and the Edit button is off, turning on the Tape Offset button enables the programmed amount of offset.

Pressing the Display, Pitch Value, or Utility button will also exit Edit mode and enter the

Display, Pitch, or Utility pages, respectively.

3.3 EDITING CONVENTIONS

• The rightmost 7-segment display shows locate times in hours, minutes, seconds, frames, subframes and samples. Subframes equal 1/100th of a frame and range from 0…99. The number of samples per subframe depends on the Tape Counter and Sample Rate settings. If the tape counter is in ABS Time mode, there are always 15 samples per subframe in 48 kHz and 14 per subframe at 44.1 kHz. If the counter is in a SMPTE Time Code mode and the sample rate is 48 kHz, Sample steps range from 0 - 15 for 30 frames/sec, 0 - 15 or 16 for

29.97 frames/sec, 0 - 18 for 25 frames/sec, and 0 - 19 for 24 frames/sec.

• A lit arrow above the subframe (SF) indicator indicates that there is a non-zero sample value. To access the samples field, with the subframe field selected press the Right Cursor button. This selects a second page that shows only the sample value.

• When editing any tape address, the cursor steps in fields (hours, minutes, seconds, frames, subframes, and samples) instead of stepping every digit.

• When editing any tape address, entering digits with the keypad automatically advances the cursor or selected field (using the Up/Down Arrows does not advance the field)

• When editing a field in the 7-segment display, the digit(s) of the selected (and currently editable) field will flash.

3-4 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 4

TAPE FORMATTING

Formatting is essential to the ADAT system. It creates a sample-accurate time reference (i.e., it’s accurate to 1/48,000th of a second when recording at 48 kHz) on each tape, in addition to block ID codes, linear control track, and other essential markers. This provides tight synchronization ó far better than SMPTE sync ó between ADAT-compatible devices, as well as precision tape counter readings and intelligent autolocation functions.

The format process first records 15 seconds of leader (the display shows LEAd), followed by two minutes of data (the display shows dAtA), then ABS time code starting at 00:00:00.00 and continuing to the end of the tape.

Caution: formatting a tape erases all material on all tracks. Always check that the tape is either blank or contains unwanted material before formatting.

You can either:

• Format a tape completely before recording (recommended)

• Format while you are recording, for as long as needed

• Extend the format of an incompletely formatted tape

Before formatting a blank tape, you must select:

• The sample rate (44.1 or 48 kHz)

• The word length (20-bit for Type II tapes, or 16-bit for compatibility with Type I

ADAT and ADAT-XT tapes)

ALESIS M20 REFERENCE MANUAL 1.06 4-1

Formatting Tape, Chapter 4

4.1 SAMPLE RATE SELECTION

Choose between 44.1 kHz (CD/consumer standard) or 48 kHz (DAT/professional standard). Here are some general hints:

• If mixing the tape through a digital mixer for a CD master, use 44.1 kHz to avoid sample rate conversion.

• If mixing the tape through an analog mixer, use 48 kHz for slightly better high frequency response.

• If you plan to transfer M20 tracks over to a hard disk system for editing, note that audio recorded at 48 kHz requires about 10% more storage capacity than the equivalent audio recorded at 44.1 kHz.

The following sample rate selection procedure assumes that Clock Source is set to INTernal.

Operation You press… You see…

Select sample rate Sample Rate

button

Sample Rate block toggles between 44.1 or 48 kHz (default) with each Sample Rate button press

About changing sample rates: The sample rate chosen during the format process does

not have to be used during playback or recording of that particular tape; the ADAT format always allows you to override the default sample rate from the tape. When loading a formatted tape, the sample rate will automatically switch to the tape’s original settings. You may change the sample rate setting to playback or record with a different sample rate, but the sample rate indicator will flash to indicate that it is not at the original setting. Changing the sample rate directly affects the pitch and speed of any audio recorded.

When extending a format, the sample rate will automatically assume the existing

format’s values. There is no way to format a tape with a “44.1” marker on one section and a “48” marker on another.

4-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 4, Formatting Tape

4.1A PULL-UP AND PULL-DOWN SAMPLE RATE SELECTION

The Sample Rate button is also used to select the respective 0.1% pull-up and pull-down rates. A pull-up is available with a 30 fps SMPTE rate only. A pull-down is available with a

29.97 fps SMPTE rate only.

Use pull-up or pull-down after a standard tape format: It is not necessary to pre-select

a pull-up or pull-down prior to formatting since the “pull” status is not recalled when tapes are subsequently reinserted. Use the pull-up/pull-down feature after formatting your tape. If you are formatting and recording simultaneously, using the pull-up/pull-down feature may be appropriate.

Operation You press… You see…

Select a Pull-up sample rate

Select a Pull-down sample rate

Return to a normal

44.1/48 kHz sample rate from a “pulled” rate

…and hold Sample Rate button then press Up button …and hold Sample Rate button then press Down button …and hold Sample Rate button then press the 0/Space button

“+0.1%” displayed in the Sample Rate block

“- 0.1%” displayed in the Sample Rate block

Sample Rate block returns to normal sample rate display (44.1 or 48 kHz)

Refer to section 16.4 for more information on pull-up and pull-down.

4.2 WORD LENGTH SELECTION

Select 20 bits unless you want compatibility with older, Type I format ADAT tapes.

Operation You press… You see…

Initiate word length selection Select word length Up or Down

Edit button, then Format button

Arrow button so that the display shows…

Display says “Format Data Type” and 16 or 20 bits The desired word length (16 or 20)

ALESIS M20 REFERENCE MANUAL 1.06 4-3

Formatting Tape, Chapter 4

4.3 FORMAT A NEW TAPE

Use only S-VHS blank tapes formulated specifically for Super VHS video or digital audio applications. Never use standard VHS tapes.

“Exercise” the tape: Before formatting, fast forward the tape to the end and rewind it to

even out the tape pack and sweep any contaminants off the tape.

Operation You press… You see…

Insert blank tape Tape into tape

chamber. Do this gently; the machine will “grab” the tape

Enable formatting Format button

(with Edit button off)

Initiate formatting Hold Record

then press Play

Display shows “noFO,” Format button flashes

All record lights turn on

Display message advises you of formatting progress

What happens between initiating formatting and the actual process of formatting depends on the current tape status.

Tape status The M20…

Unformatted, at start of tape Begins formatting immediately Unformatted, partway through tape Rewinds, then begins formatting While rewinding from current position, goes from unformatted to previously formatted portion

Formatted, in Leader or Data section of tape Formatted, in Audio section of tape Extends format after entering record

Disables formatting to avoid reformatting a partially formatted tape. Either extend the format from this point on, or for a complete format, rewind, then initiate formatting Rewinds, then begins formatting

(see section 4.5 for information on extending a format)

4.4 RECORD TRACKS WHILE FORMATTING

The procedure is similar to standard formatting, except:

• Record-enable (section 5.4) any tracks to be recorded prior to pressing the Format button.

• No audio will be recorded before the counter shows 00:00:00.00 ABS time.

4-4 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 4, Formatting Tape

4.5 EXTEND A PARTIALLY-FORMATTED TAPE

• The procedure is similar to standard formatting, except:

• Make sure the tape is located at least 20 seconds before the end of a previously-formatted

section before attempting to extend the format.

• Regardless of the current sample rate and word length, these will change automatically to match the original format.

• After pressing the Format button, press and hold Play then press Record. Formatting will begin when a lock is established.

Note: The above assumes the tape is somewhere after ABS time 00:00:00.00. If the tape to

be extended is in the leader or data sections (i.e., prior to ABS time 0:00:00.00), entering Format mode automatically rewinds the tape to the leader and begins reformatting. While rewinding, the display shows “…format begun” and the Rewind button will light to remind you that the M20 must format over from the tape’s leader and data sections.

4.6 END FORMATTING

When the tape reaches the end, formatting ends automatically and the tape will stop.

To stop formatting prior to the end-of-tape, press Stop. You cannot simply punch out with the Play button.

4.7 CERTIFY TAPE FORMAT

After formatting, consider playing the tape through to the end to check for a suitably low error count (see section 13.20), thus verifying the tape’s integrity.

4.8 REFORMATTING: CAUTION!

Do not stop in the middle of re-formatting over a previously formatted tape. When the tape transitions from the newly formatted section to the previously formatted section, there will be timing discontinuities, and you will not be able to record anything over the transition. Either re-format the entire tape from beginning to end, or rewind a bit and extend the existing format.

ALESIS M20 REFERENCE MANUAL 1.06 4-5

Formatting Tape, Chapter 4

4.9 LOCK OUT FORMATTING (SAFE MODE)

You may lock out the format option to prevent accidental formatting. This remains in effect, even if you insert different tapes, until the setting is changed. To lock out formatting:

Operation You press… You see…

Select safe function Edit button, then

Format button until display shows Page 2

(Format Safe) Select format safe status

Up or Down

Arrow button to

choose On or Off

respectively

Display says “Format Safe:” and format safe status (on or off)

Selected format safe status

4.10 BULK ERASING

You can bulk-erase M20 tapes with a video tape eraser.

4.11 RECORDING A “BENCHMARK” TAPE

Alesis recommends that you format and record a new tape with any signal, such as a test tone, in a single pass with no overdubs during the first week of operation. Store this tape in a safe, dry location and don’t use it for any other purpose. Such a “benchmark” tape is useful to determine if the error correction rate is increasing over time because the heads need to be cleaned, or if a tape is defective.

4-6 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 5

TRACK RECORD ENABLING AND

MONITORING

5.1 TRACK BASICS

The M20 can record a total of 10 tracks:

• 8 digital audio tracks. These record standard audio signals, either from the analog inputs, optional AES/EBU card, or ADAT Optical Interface.

• 1 analog Aux track. This track records audio information from the Aux input, along with any of the eight audio tracks routed to the Aux track. This provides quality scrubbing (which is difficult to do solely in the digital domain) and the ability to hear audio from the Aux output during rewind, fast forward, and autolocate operations. During Search operations, the Aux track can be routed to any of the eight standard audio track outputs (see section 6.5).

• 1 time code track. This track records only SMPTE/EBU time code information, and stores this data digitally on tape. It receives its input from the Time Code In jack if the TC Source is set to External (section 11.3), or from the Internal Time Code Generator if the TC Source is set to Internal.

SMPTE vs. ABS time code: The ADAT ABS time reference is separate from this SMPTE

time code track, and is written in a subcode of the tape automatically as part of the format operation covered in Chapter 4.

To record, a track must first be record-enabled (see section 5.4; the record enable button light will flash).

Aux and TC track record enabling: The Aux and TC tracks cannot be record enabled

simultaneously. For example, if the Aux track is record enabled and the TC Track record enable button is pressed, record will disable on the Aux track and the TC Track will become record enabled. This will occur in any transport mode, so if a record is in progress on the TC Track, pressing the Aux track record enable button will punch-out of the TC Track.

You typically press the Play and Record transport buttons to allow track-enabled tracks to begin recording, although you can also use a footswitch (section 8.6e) and/or program automatic punch in points (sections 8.8a and 8.8c). During recording, any armed Record Enable buttons stay lit steadily.

ALESIS M20 REFERENCE MANUAL 1.06 5-1

Track Record Enabling and Monitoring, Chapter 5

5.2 TRACK INPUT ENABLES

An input-enabled track monitors the associated input signal. There is one Input Enable button (with associated indicator light) for each track (10 total). The Input Enable button toggles between monitoring the input signal or monitoring the tape.

Operation You press… You see…

Enable track input (monitors input signal) Disable track input (monitors tape signal)

The track Input Enable button until… The track Input Enable button until…

5.3 AUTO INPUT SWITCH

This switch determines whether or not a record-enabled track (audio or aux) will monitor from input or tape automatically, depending on the recording context. Disabling Auto Input is preferred for recording basic tracks, while Auto Input is usually enabled during overdubbing and punching.

Track input light turns on Track input light turns off

What the tracks monitor

Record-enabled tracks monitor the… Non-record-enabled tracks monitor the…

5.4 RECORD ENABLE

Pressing a track’s Record Enable button allows it to record when the M20 is in Record mode.

Any number of channels can punch in simultaneously, or punch out simultaneously, and any channel or channels can punch in or out while other channels are in record.

Operation You press… You see…

Record enable a track The track Record Enable

Turn off record enable for a track Punch in using Record Enable button

Punch out using Record Enable button

Auto Input Off

Input signal Input while recording or stopped, tape

Tape Tape while playing or recording, input

button

The track Record Enable button While in Record mode and the tape is running, press Record Enable button While recording, press Record Enable button

Auto Input On

while playing

signal when stopped

The Record Enable light flashes, then lights solid while recording The Record Enable light turns off Record Enable button lights solid

Record Enable button turns off

If you press Play and Record with no tracks record-enabled, the Record light will flash indicating a Record Pending mode. When the Record light is lit (or flashing if Rehearse is enabled; see section 8.7), pressing individual track Record Enable buttons can punch individual tracks in or out independently. The Record light will remain lit (or flashing in Rehearse mode) until you punch out of Record, usually by pressing Play or any other transport key.

5-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 5, Track Record Enabling and Monitoring

5.5 SAFETY MODE (ALL SAFE)

To prevent any accidental recording, pressing All Safe places all tracks (channels 1-8 plus Aux and TC) into a safe (non-record ready) mode. This is particularly useful when mixing.

Operation You press… You see…

Place all tracks into a safe (non-recordable) mode

Exit safe mode All Safe All track record ready

All Safe All track record ready

5.6 MONITOR INPUTS (ALL INPUT)

Pressing All Input sets all tracks, excluding the TC track, to monitor the input signal regardless of the record-ready/auto-input status (section 5.3). Tape playback cannot be heard while All Input is on. While enabled, the track input buttons will have no effect. This is useful for live recording situations.

lights and auto-enabled track input lights turn off

lights, and auto-enabled track input lights return to their state prior to pressing All Safe

Operation You press… You see…

Have all tracks (except TC) monitor the input signal Exit All Input mode All Input All Input Enable lights

This function can also be used while All Safe is on.

All Input All Input Enable lights

(except TC) are lit solid

return to their state prior to pressing All Input

ALESIS M20 REFERENCE MANUAL 1.06 5-3

Track Record Enabling and Monitoring, Chapter 5

5-4 ALESIS M20 REFERENCE MANUAL 1.06

DIGITAL/ANALOG INPUT

SELECTION AND ROUTING

6.1 DIGITAL SOURCE

When using digital inputs, this function selects one of two or three digital input options. The I/O card option will appear in the display only if an I/O card (such as the Alesis AES/EBU card) is installed in the machine. Settings are retained in memory.

Operation You press… You see…

Select ADAT optical digital input (default) Select digital track copy function Select I/O card as the digital input

The Digital Source button until you see… The Digital Source button until you see… The Digital Source button until you see…

CHAPTER 6

ADAT optical in the Dig Source block Track Copy in the Dig Source block I/O card in the Dig Source block

For more information on Track Copy, see section 6.4b.

6.2 INPUT SELECT

Not valid in Track Copy mode: If the Digital Source has been set to Track Copy, you

cannot enter Input Select mode. In Track Copy mode, only internal tape tracks may be recorded.

Inputs can come from digital or analog signal sources. Use the Input Select button to choose digital or analog inputs as the signal source for each adjacent track pair (1/2, 3/4, 5/6, or 7/8). In addition, all tracks may be set to receive analog or digital.

If no track buttons are pressed within 10 seconds of entering Input Select mode, the M20 automatically exits.

Operation You press… You see…

Enter Input Select mode The Input Select button Input Select display

Select analog or digital input source

Select all channels for digital input Select all channels for analog input (default) Exit Input Select mode The Input Select button Input Select indicator

indicator flashes Either Track Input button of a stereo pair to toggle between analog or digital source for the track pair The All Input button A and D indicators all

The All Safe button A and D indicators all

A and D indicators at the

base of the VU meters

indicate analog or digital

input, respectively

show D

show A

turns off to confirm the

exit

ALESIS M20 REFERENCE MANUAL 1.06 6-1

Input Selection and Routing, Chapter 6

If no digital signal input is detected, the D indicators for the channel(s) without a digital signal source will flash until signal is detected.

6.3 TRACK OUTPUT SELECTION

It is not necessary to select an output destination. Audio data always appears simultaneously at the analog, ADAT optical, and optional AES/EBU outputs. Audio always appears at the same-numbered output it was recorded on.

6.4 INPUT SIGNAL ROUTING (ANALOG AND DIGITAL)

The Input Route button selects how the M20’s analog and digital inputs are routed to the 8 tape channels. If no track buttons are pressed within 10 seconds of entering Input Route Mode, the M20 automatically exits.

Operation You press… You see…

Enter Analog Routing page (available only if at least one track pair’s input has been set to “A” using Input Select mode) Choose Analog Routing Input (white button

Enter Digital Routing page (available only if at least one track pair’s input has been set to “D” using Input Select mode)

Choose Digital Routing See section 6.4b See Section 6.4b Exit Input Routing mode Press the Input Routing

The Input Routing button Every track’s A indicator

lights, display says “Select analog input trks”

Odd/Even lights tracks 1 below record) for Track 1 or 2 to select Odd/Even, Track 3 or 4 to select Half & Half, Track 5, 6, 7, or 8 to select One-to-One (default; see diagram below) The Input Routing button again (or press twice if not already in Input Route mode)

button until the Input Route indicator turns off

&2, Half & Half lights

tracks 1—4, One-to-One

lights tracks 1—8

Every track whose Input

Select is set to Digital’s D

indicator lights, display

says “Select optical src

trks” or “Select I/O card

src trks”

Channel indicators and

track select buttons

return to their normal

status

Analog and Digital Routing not available in Track Copy mode: If the Digital Source

has been set to Track Copy, Input Routing sets which internal tape tracks will be copied (see 6.4b).

6-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 6, Input Selection and Routing

6.4A ANALOG INPUT ROUTING

The three analog routing modes accommodate 2, 4, or 8 bus mixing consoles. With two buses, connect them to inputs 1 and 2. With four buses, connect them to inputs 1 through 4. With 8 buses, direct outs or a patch bay, run each bus out to its like-numbered M20 input. The analog routing choices are:

• Odd/Even: Press either the Track 1 or 2 button. Input 1 feeds channels 1, 3, 5, 7, and Input 2 feeds channels 2, 4, 6, 8. To record on an odd-numbered track, route the signal(s) to bus #1 or left. To record onto an even-numbered track, route the signal(s) to bus #2 or right. By simply putting the desired track into record, the proper signal will get there, even though it is not connected directly to the track’s input jack.

• Half & Half: Press either the Track 3 or 4 button. Input 1 feeds channels 1, 5; input 2 feeds 2, 6; input 3 feeds 3, 7; input 4 feeds 4, 8). To record on tracks 1 or 5, route the signal(s) to bus #1. Likewise, to record onto tracks 2 or 6, route the signal(s) to bus #2, and so on.

• One-to-one: Press either the Track 5, 6, 7, or 8 button in Input Routing mode. This is the power-on default, where each input feeds its corresponding channel. To record on track 1, send the signal to mixer bus 1, to record on track 2 send the signal to mixer bus 2, etc. This is also the recommended mode when feeding the M20 from a mixer channels’ direct outs.

Alternate method: In Input Routing mode for analog inputs, the All Safe button selects

the odd/even configuration and the All Input button selects one-to-one.

ALESIS M20 REFERENCE MANUAL 1.06 6-3

Input Selection and Routing, Chapter 6

6.4B DIGITAL INPUT ROUTING

The Digital Source setting (section 6.1) influences the digital input routing process. This feature makes it possible to record incoming digital data on any track desired, without manually repatching.

If digital source = ADAT Optical:

Any of the 8 incoming optical channels may be individually selected or de-selected with the Track Input buttons while in Digital Routing mode.

• A lit track input light indicates that the incoming ADAT optical channel is a digital source.

• If a track input light is dark, that means the incoming ADAT optical channel will be skipped as a source.

• Pressing the All Input button selects all eight channels as optical sources (this is the normal state).

• Pressing All Safe turns off all channels, which results in a one-to-one routing (just as if all 8 channels were selected as sources). All Safe simply “clears the slate” for additional digital source channel selections.

If digital source = I/O Card (AES/EBU):

Because AES/EBU is a 2-channel digital format, only channel pairs (1-2, 1-4, or 1-8) may be selected or de-selected. Pressing the All Input button selects all channels. As in ADAT Optical, a lit track input light indicates that the channel is a digital source.

If digital source = Track Copy:

Any of the 8 channels, to a maximum of 4 total, may be individually selected or de-selected. A lit track input light indicates that the channel is a track copy source, i.e., the selected channels are the internal source channels eligible for digital bouncing within a single M20. Pressing the All Input button selects channels 1 through 4 as track copy sources.

• No more than 4 tracks may be copied within a single machine, so if 4 source tracks are already selected, one must be de-selected before you can select another track.

• A digital source track cannot be record-enabled in Track Copy mode. If you try, the message “Source cannot equal dest” will appear in the display.

• When copying tracks, any track delays (section 11.9) will be in effect.

• Pressing All Safe deselects any track copy source channels.

6-4 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 6, Input Selection and Routing

6.4C RECORD-ENABLING THE DESTINATION TRACKS

In Digital Routing mode, inputs need not be routed only to same-numbered tracks. Any selected digital source inputs can be re-routed to any record-enabled destination tape tracks, in ascending order.

Example: if ADAT optical source inputs 1 and 5 are selected using Input Routing, and

tracks 3 and 4 have digital sources (“D” selected as Input Select) and are recordenabled, then incoming digital audio on optical channel 1 goes to track 3, and incoming digital audio on input 5 feeds track 4.

If more destination tracks are enabled than there are source inputs, the source inputs will repeat (cycle). Note that this technique allows copying a single incoming signal to multiple tracks.

Example: if in the previous example tracks 7 and 8 were record-enabled as well as tracks

3 and 4, audio from input 1 would go to tracks 3 and 7, and incoming audio from input 5 would feed tracks 4 and 8.

If all 8 source tracks are selected, then no digital routing occurs as this gives a one-to-one relationship (the power-on default).

Example: if all eight ADAT optical sources are selected, and tracks 3 and 4 are record-

enabled, they will receive digital audio from ADAT optical channels 3 and 4 respectively.

The track copy function works the same way. If Digital Source is set to Track Copy and tracks 7 and 8 are the only tracks selected in Input Routing mode, track 7 will be copied on the lowest-armed track and track 8 will be copied onto the next higher armed track. For example, if tracks 2, 4, 5 and 6 are armed, track 7’s data will be copied onto tracks 2 and 5 and track 8 onto tracks 4 and 6.

ALESIS M20 REFERENCE MANUAL 1.06 6-5

Input Selection and Routing, Chapter 6

6.5 AUX ROUTING (INPUT AND OUTPUT)

The analog Aux track of the M20 is a unique feature that has special application in Search mode, because it allows you to hear audio at extremely slow speeds for cueing. The Aux Routing feature allows you to automatically mix other tracks for recording onto this track.

The back panel Aux Input is permanently routed to the Aux track. The Aux Routing button selects whether additional inputs will also feed the Aux track (e.g., if tracks 1 and 6 are routed to the Aux track, then the Aux track will record tracks 1 and 6 and the Aux Input). You can route any track or group of tracks to the Aux track. If no track buttons are pressed within 10 seconds of entering Aux Route mode, the M20 automatically exits this mode.

It is also possible to automatically record a copy of whatever tracks are currently armed onto the aux track, so the Aux track always contains the last overdub only. This is called “Auto” mode.

Operation You press… You see…

Enter Aux Route mode The Aux Routing button Aux Route indicator

Select Aux tracks manually

Select Aux tracks automatically (this directs all record-enabled tracks to the Aux track)

Exit Aux Route mode The Aux Route button, or

The desired channels’ Track Input buttons

Aux Input button (white button above Aux Rec Enable)

wait 10 seconds without pressing any buttons

flashes Aux indicator (below VU meter for each selected track input) lights “Auto” indicator below the Aux track input lights; any individual track “Aux” indicators disappear Aux Route indicator turns off; channel indicators and track select buttons return to their normal status

Aux routing takes effect only after Record: The routing to the Aux track changes only

upon entering Record mode. Thus, even with Auto Routing enabled, the current manual or previous auto routing remains in effect until the Aux track goes into record.

Aux output routing: When in Jog/Shuttle mode (section 8.4), the Aux output routing

always follows the input routing. Example: If tracks 1 and 5 are routed to the Aux track, then the Aux track output (which sums tracks 1 and 5 and feeds them to the Aux Out) will appear on both outputs 1 and 5, unless tracks 1 and 5 are selected as inputs. This makes it unnecessary to keep a channel on the console dedicated to the Aux output.

If you turn off Auto mode (press Aux Routing, then press the Aux Input button), the Aux routing tracks do not return to what had been selected manually prior to automatic Aux selection; they will show the tracks last armed and recorded.

6-6 ALESIS M20 REFERENCE MANUAL 1.06

With digital recording, it is very important not to exceed the available headroom (and with 20 bits to play with, you have so much dynamic range that there’s no need to push it). The M20 provides three different metering modes to make it easier to avoid overloads.

7.1 METER MODE SELECTION

The Peak Mode button cycles through three different meter modes:

• No Peak Hold. Meter levels reflect the current input signal levels.

• Momentary Peak Hold (default). Although the meter reflects the current input

signal, the meter also retains the peak level briefly. This is useful if the signal to be recorded has short transients, which you might miss seeing when they occur.

• Continuous Peak Hold. The meter also reflects the current input signal, but retains the highest peak until cleared. Thus, if you can’t monitor a track continuously during the recording process, you can look at the meter after the recording is over to see the highest recorded peak.

CHAPTER 7

METERING

As you cycle through these options, the main display briefly shows the selected mode.

7.1A CLEARING PEAKS

With continuous peak hold, you will eventually want to clear the peak level indicators on all 8 channels. Press Peak Clear to reset the meters.

ALESIS M20 REFERENCE MANUAL 1.06 7-1

Metering, Chapter 7

7.2 METER SETUP

The VU meter scaling, headroom, decay time, and peak hold time are all adjustable using the Display menus. The Display button is in the lower left group of buttons beneath the meter display.

Scaling determines whether the meter range is -72 dB to 0 (Normal; this is the default) or -2.0

to +2.0 (Fine).

Headroom sets the headroom amount for the Fine VU meter mode (it does not affect the

normal mode) by letting you specify what value the 0 dB marking represents. The value ranges from 2 to 22 dB, in 1 dB steps (default = 15 dB).

Decay sets the time for a meter segment to turn off after the signal goes below that level, with

a range of 1 to 99. Each step represents 5 milliseconds, with higher numbers standing for longer decays. The maximum decay of 99 means a segment will hold for 500 ms. (1/2 second). Default = 10.

Peak hold time sets how long peaks will be held when the meters are in momentary Peak

Hold mode, from 1 to 99. Each step represents 250 milliseconds, with higher numbers standing for longer holds. The maximum decay of 99 means a segment will hold for

24.75 seconds after level has fallen. Default = 8

Operation You press… You see…

Enter VU meter scaling setup Edit VU meter scaling Up/Down buttons Display shows Normal

Enter VU meter headroom page Edit VU meter headroom Keypad or Up/Down

Enter VU meter decay page Edit VU meter decay Keypad or Up/Down

Enter VU peak hold page Display button again Display says VU Peak

Edit VU peak hold Keypad or Up/Down

Display button Display says VU Meter

Scale

or Fine scaling

Display button again Display says Fine

Headroom

Display shows amount of buttons to choose the headroom amount Display button again Display says VU Decay

buttons to choose the amount of decay

buttons to choose the peak hold time

Fine headroom in dB

Display shows amount of

meter decay time

Hold

Display shows amount of

peak hold time

7-2 ALESIS M20 REFERENCE MANUAL 1.06

TRANSPORT CONTROLS AND

BASIC RECORDING

The transport buttons include Rewind, Fast Forward, Stop, Play, Record, and Eject. The transport movement may also be controlled by the jog/shuttle wheel, or various built-in automatic features.

8.1 ABOUT THE TAPE COUNTER

The tape counter, located on the right side of the right display, shows the current tape location. The Tape Counter button selects the counter mode (the 10-digit location counter is above the Tape Counter switch). Pushing the switch cycles through three different modes.

• ABS Time references the current tape location to the proprietary sample-accurate ADAT time code formatted into each ADAT tape.

• Relative references the current tape location to the relative zero location. The relative zero point is set by entering an absolute time value into the Locate 00 address. That value is subtracted from the absolute time code value when the tape counter display is in Relative mode.

CHAPTER 8

• SMPTE references the current tape location to SMPTE (i.e., ABS + any SMPTE offset,

Note: this is NOT necessarily the SMPTE time code printed onto the T/C track. That

8.2 STOP

Press to stop the tape transport (Stop button lights steadily). The tape stops moving, but remains threaded around the head drum.

The tape will unthread (i.e., disengage from the head drum) automatically if no transport movement occurs during a user-definable timeout period (default = 4 minutes; see section

13.9). Stop will flash. To re-thread the tape, press Stop again (it lights steadily). Note that entering play from the unthreaded position takes slightly longer than when the tape is already threaded, due to the time required to wrap the tape around the head drum.

as described in section 11.6a).

code is displayed in the Reference counter on the left side of the display.

ALESIS M20 REFERENCE MANUAL 1.06 8-1

Transport Controls and Basic Recording, Chapter 8

8.3 PLAY

How Play affects tape motion depends on the tape’s status.

If the tape is…

Stopped Playback Play button lights steadily Playing No change (playback continues) Play button lights steadily Formatting No change (formatting continues) Play button lights steadily Locating Playback after the locate is

Locating Pressing Play twice stops

Recording Punch out, and enter Play Play button lights steadily

Pressing Play causes… You see…

complete

autolocation and begins playback

8.3A PLAY BUTTON AND SYNC STATUS

When the M20 is playing and in sync, the Locked indicator (under the last field of the tape counter) will light solid.

If the M20 loses sync while playing (either as a master or as a slave), the Locked indicator will turn off.

8.4 JOG/SHUTTLE WHEEL AND SEARCH

The jog/shuttle wheel provides convenient access to capstan-engaged rewind, fast forward, and “scrub” functions (in scrub mode, audio normally comes from the analog Aux track). In master/slave situations, the master’s jog/shuttle wheel controls the slaves, regardless of the slave’s physical wheel position.

Play light flashes during locate, then stays lit when locate is complete Play button lights steadily

Pushing the Jog/Shuttle wheel selects between the two modes, as indicated by LEDs above the Search button. The Search button works with the Jog/Shuttle wheel, as described toward the end of this section.

8.4A JOG MODE

Jog advances or rewinds the tape at a rate proportional to thespeed of wheel rotation. This allows you to move the tape as if you were “rocking the reels” on a n analog machine.

Action… Result… You see…

Turn wheel clockwise

Turn wheel counterclockwise

When in Jog mode and the transport is idle, the Search and Play buttons will remain lit, and the Stop button will light steadily (indicating that jogging is paused).

Tape moves forward at a rate proportional to rotation speed (1/8X to 1X play speed) Tape move in reverse at a rate proportional to rotation speed (1/8X to 1X play speed)

The Search and Play buttons light, and right arrow above wheel lights

The Search and Play buttons light, and left arrow above wheel lights

8-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 8, Transport Controls and Basic Recording

8.4B SHUTTLE MODE

Shuttle advances or rewinds the tape at a rate proportional to the degree of wheel rotation. The greater the degree of rotation from the center detent, the faster the rate.

Action… Result… You see…

Turn wheel clockwise

Turn wheel counterclockwise

Push lit Search button while in Shuttle mode

Tape moves forward at a rate determined by amount of rotation (from 1/4X to 16X play speed) Tape moves in reverse at a rate determined by amount of rotation (from 1/4X to 16X play speed) Transport goes into Play Search and Transport Stop

The Search and Play buttons light, and right arrow above wheel lights

The Search and Play buttons light, and left arrow above wheel lights

buttons goes out, Play remains illuminated

8.4C SEARCH BUTTON

The Search button toggles transport control between the Jog/Shuttle wheel (Search button lit) and the transport buttons (Search button dark), making it easy to go in and out of Play mode while using the Jog or Shuttle function to locate a specific piece of audio.

Action… Result… You see…

Push lit Search button while in Jog or Shuttle mode (disable Search mode) Push unlit Search button while in Jog or Shuttle mode (enable Search mode)

Search mode can be initiated simply by turning the jog/shuttle wheel, or enabled only by pressing the search button, according to the settings on Page 10 in the Utility menu (section

13.10).

Transport goes into Play Search and Transport Stop

buttons go out, Play remains illuminated

Transport enters jog/shuttle mode: If in Jog mode, stops; If in Shuttle mode, moves in the direction and speed indicated

Search and Transport Stop buttons light, Play remains illuminated

Direction arrows may be lit in Shuttle mode

ALESIS M20 REFERENCE MANUAL 1.06 8-3

Transport Controls and Basic Recording, Chapter 8

8.4D SEARCH MASTER

This function (available only in the ID 1 master M20 in a system) accommodates situations where you want to use jog on a machine that is not the master (e.g., to find a particular point on the tape of a slave ADAT only). In this case, you don’t want the slave M20 to follow the master, but instead, to act as a “temporary locate master” so all machines (including the ID 1 master) park where the designated search master machine parks after a jog or shuttle operation. The default Search Master machine is ID1. Search Master status is not retained when the power goes off.

To set which online M20 controls the parking address for all other M20s in a system:

1. Press and hold Search for 2 seconds to enter Search Master Edit mode. The display shows “Search Master: n” (n = 1 — 8 or All).

2. While continuing to hold Search, use the numeric keypad buttons (1-8, 0) or Up/Down buttons to select a search master (default is 1). Releasing the Search button exits the edit mode without changing the Search mode status.

Selecting a machine other than ID 1 as a search master and activating Search mode (Jogging or Shuttling) causes the display to indicate momentarily “Machine n Search Master” (n = 1 -

8) or “No Search Master” when All is selected. If you pause a search, ID 1 will query the

search master, update ID 1’s tape counter, and locate all connected machines to the position of the designated search master.

When search master equals All, ID 1 will not send a locate command to the slaves. All decks will remain parked after a search.

Releasing the Search button exits Search Master Edit mode, and the M20 reverts to the display prior to selecting the Search Master.

Note: ID1 must remain online, and the user must observe the time code display when

actively jogging or shuttling because when a slave is the search master, the master’s tape counter display will only reflect ID1’s tape position until Search mode is paused and ID1 has located to the search master’s tape position.

8-4 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 8, Transport Controls and Basic Recording

8.5 OTHER TRANSPORT BUTTONS

You press… If tape is

stopped

Eject Tape ejects Tape stops

Eject on Master deck (ID 1)

Hold Peak Clear while pressing Eject

Rewind Tape begins

Rewind + Play (Review mode)

Fast Forward Tape fast

Fast Forward + Play (Cue mode)

Master and slave tapes eject

Master tape only ejects, MMC Stop command is sent to slaves

rewinding at 16X play speed,then accelerates to 85X play speed Tape rewinds at 3X real time and plays pieces of audio

forwards at 16X play speed, then accelerates to 85X play speed Tape fast forwards at 3X real time and plays pieces of audio

If tape is moving You see…

prior to ejection Tape stops prior to ejection

Master tape ejects, MMC Stop command is sent to slaves

Same Rewind button lights

Same, except if recording, punches out first Same Fast Forward button

Same, except if recording, punches out first

Tape exits cassette well, eject button lights Tape exits master and slave cassette wells, eject button lights Tape exits master cassette well, eject button lights

steadily

Play button lights steadily, Rewind light flashes

lights steadily

Play button lights steadily, Fast Forward light flashes

To end a Cue or Review operation, press Play, Stop, Rewind, Fast Forward, or Search.

ALESIS M20 REFERENCE MANUAL 1.06 8-5

Transport Controls and Basic Recording, Chapter 8

8.6 RECORD

This button’s operation depends on whether One-Button Record (section 13.4) is enabled or disabled.

You press… If tape is

stopped

Record, and while holding, press Play Record Recording

If the Format light is lit, entering Record mode will format the tape (see Chapter 4 on formatting).

Recording begins

begins

If tape is moving You see…

Recording begins

No change in existing status

Record button lights

If recording, record button lights

8.6A PUNCHING INTO RECORD

There are five ways to punch into record while the tape is playing.

• Press and hold Record, then press Play at the punch-in point (or vice versa).

• With One-Button Record enabled, press Record at the punch-in point.

• Use the Record Enable buttons for enabled source inputs. If no tracks are record-enabled

and you press Play and Record, the Record button will flash to indicate Record mode is pending. At the punch-in point, press the appropriate Record Enable buttons (dynamic punch, section 13.13, must be enabled for this function to work).

• Use a footswitch (section 8.6e).

• Program Auto Record (section 8.8).

8.6B PUNCHING OUT OF RECORD

There are five ways to punch out of record.

• Press Stop. The transport punches out of record, then stops.

• Press and hold Record, then press Play.

• Press Play.

• Use the footswitch (section 8.6e).

• Turn off a track’s Record Enable button (dynamic punch, section 13.13, must be enabled

for this function to work).

8-6 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 8, Transport Controls and Basic Recording

8.6C RECORD WRITE-PROTECTION

S-VHS cassettes have a write-protect tab on the side of the tape opposite the “door” that, when removed to create a small “window,” prevents recording. The M20 senses the writeprotect tab status. If the tape is write-protected, the M20 will not allow recording or formatting to take place. Attempting to record causes the display to show “ERROR - Write Protected,” and the transport will enter or remain in play.

How to Override Write-Protection

It is possible to record on a tape that has been write-protected (without resorting to the usual tactic of taping over the tab). A tape must be in the transport to perform this procedure:

Operation You press… You see…

Enable write-protect override

Disable write-protect override

Sense Write Protect auto-reset: Write-protect override resets to the default “Sense Write

Protect” status automatically whenever the tape is ejected.

Press and hold Peak Clear, then press transport Record button Press and hold Peak Clear, then press transport Record button

Display says “Override Write Protect”

Display says “Sense Write Protect”

8.6D RECORDING WITH A FOOTSWITCH

If any tracks are record-enabled and the tape is playing, pressing the punch footswitch is equivalent to pressing Record and Play.

If the M20 is already recording, pressing the punch footswitch exits Record mode but the transport continues to play.

If you plug in a footswitch while the M20 is on, turn the M20 off and then on again so the machine can sense whether the momentary footswitch is a normally open or normally closed type.

Note: Footswitch-controlled recording also works in conjunction with Rehearse mode (section 8.7) and Auto Record mode (section 8.8).

8.7 REHEARSE MODE

Rehearse mode allows checking punch point accuracy without actually entering Record mode. Record-enabled tracks will switch from tape monitor to input monitor at the punch-in point, and back to tape monitor at the punch-out point.

Operation You press… You see…

Enable Rehearse mode Rehearse button Rehearse switch lights,

Disable Rehearse mode Rehearse button Rehearse switch light

Record light flashes (not lit solid) while rehearsing the punch

turns off

ALESIS M20 REFERENCE MANUAL 1.06 8-7

Transport Controls and Basic Recording, Chapter 8

8.8 AUTO RECORD

In Auto Record mode, you can program punch in and out points. Pressing Play and Record prior to the punch-in point causes the M20 to automatically punch in and out at the programmed points.

You first must set auto-punch points, then enable the function. The auto-punch in and out points default to autolocation points 98 and 99 respectively. These points automatically store the locations of the last manual punch in and out, so anytime you have gone into record manually you can repeat that punch exactly using Auto Record mode if desired.

If the auto punch-out location address is lower than the punch-in address, the Auto Record function will be disabled (light off), and attempting to enable this causes an error message in the display.

8.8A SETTING AUTO RECORD PUNCH POINTS

To edit the auto record in and out points (as displayed in the right side of the main display), follow the steps below.

Operation You press… You see…

Display punch in or out point

Choose specific location as punch in or punch out point Edit punch in or punch out point

Disable punch out point Both Up and Down

Exit Auto Record setup Press Edit button Display returns to

Edit button followed by the Auto Record button (Auto Record toggles between displaying punch in and punch out points) Up/Down buttons Display shows new

Cursor buttons, then enter numbers (keypad, Up/Down buttons, Copy Tape Location) in the appropriate fields

buttons simultaneously (cursor must not be in a time field)

Display shows punch in or out point

punch in or punch out point Field to be edited flashing, then replaced by your entry

Display shows Out Pt Disabled

normal

8-8 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 8, Transport Controls and Basic Recording

8.8B ENABLE AUTO RECORD

To enable and disable Auto Punch, make sure the machine is not in Edit mode (if necessary, press the Edit button so that it turns off).

Operation You press… You see…

Enable Auto Record Auto Record button Auto Record button

lights

Disable Auto Record Auto Record button Auto Record button

turns off

Use Auto Record Press Play and Record

prior to the punch in point

Note: If the currently selected locate number equals the punch-in locate number, then the In label lights in the Locate Point block. Similarly, if the currently selected locate number equals the punch-out locate number, then the Out label lights in the Locate Point block.

Record buttons light solid during punched region

8.8C SET AUTO PUNCH POINTS “ON THE FLY”

Whenever you punch in/out manually (as opposed to auto-record), the default auto-punch points assume the times of the manual punch points, and stores them in locations 98 and 99.

Note: This is not the case if punching is enabled/disabled with the Record Enable buttons.

ALESIS M20 REFERENCE MANUAL 1.06 8-9

Transport Controls and Basic Recording, Chapter 8

8-10 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 9

AUTOLOCATION

The M20 can autolocate to specific points on the tape. Its built-in memory contains 100 different location points, complete with 8-character names. Locate points are used not only for convenience, but in several other functions of the M20 such as Auto Record and Tape Offset. These points are saved in the memory of the M20 even when power is turned off, and may even be saved to the data header of each tape or to a MIDI file via a sysex dump.

The Locate button is positioned next to the other transport buttons (left of the Rewind button). The currently chosen point is shown in the lower right corner of the main display. Normally, the upper line of the display shows the location number and name.

Tip: Most M20 users find it convenient to leave the display in Locate Select mode, and

the reference counter in Locate Point mode. If a Display, MIDI, Vari Speed, or Utility button (these are grouped next to the green Online button) are pressed, they will take over the top line of the main display, and their button will light. Press Locate Select to return the display to its default state.

The Locate Point display uses the ADAT’s ABS time as a reference, not the SMPTE time code track. It can, however, display locate points in SMPTE, Absolute, or Relative modes. If the Tape Counter (lower left counter in the main display) is in SMPTE, it uses the fixed SMPTE offset (set in the SMPTE Chase menu) to calculate its value. If the Tape Counter is in Relative mode, it will subtract the Locate 00 number to calculate its value.

9.1 ENTERING, SELECTING, AND EDITING LOCATION POINTS

9.1A S

ET LOCATE

Pressing the Set Locate button (located just above the Stop button) at any time stores the current tape location (rounded to the nearest subframe) into the next memory location for later recall. If the Location point is currently 00, the first press of Set Locate stores the current ABS time into Locate point 01 (shown in the display lower right). The next locate point is 02, the next 03, and so on up to a maximum of 97. Any previous location address, but not its name, will be overwritten when using Set Locate. The location block also indicates whether the location point is one of four special locations (In, Out, Start, or End).

Note: Set Locate will not increment to points 98 and 99, as these are reserved for punch points set manually. You must select these points with the Up/Down Arrow buttons to update them with the Set Locate function.

9.1B COPY TAPE LOCATION

Pressing the Copy Tape Location button stores the current tape location from the tape counter to the currently-showing locate point indicator; this function is useful for grabbing location points “on the fly,” as well as for manual auto-punch and loop points. Unlike Set Locate, doing this does not increment to the next location point number. You must increment manually.

ALESIS M20 REFERENCE MANUAL 1.06 9-1

Autolocation, Chapter 9

To select and edit location points:

Operation You press… You see…

Copy Tape Location to memory

Store Locate Point Set Locate button Locate Point display

Select Locate Point Locate Select button, then

Edit Locate Point Locate Select button, then

Edit Locate Name Locate Select button, then

Go to Locate Point After selecting the

Locate to Zero* Locate 0 button The Rewind or Fast

Copy Tape Location button

Up/Down Arrows or number keys to select the desired location point

press Cursor Left/Right to select the field to be edited (it will flash). Use Up/Down Arrows, or number keys to enter the new value

Enter/Name button. Enter the name.

desired Locate Point (using Select Locate mode), press Locate.

Tape counter time (display left side) is copied to the Locate Point indicator on the display’s right side (Reference Counter).

shows the current time; the location block shows the locate point number Locate Select display shows the location point number and name; the locate point block shows the locate point number; Reference Counter (if in Locate Pt mode) shows the point time. Locate Point display (Reference Counter) shows the location point time; the locate point block shows the locate point number

Locate point block shows the locate point number

The Rewind or Fast Forward button flashes to indicate the direction of the search. The Locate button stays lit until the tape reaches its destination.

Forward button flashes to indicate the direction of the search. Locate 0 lights stays lit until the tape reaches its destination.

*Whether the tape counter display is ABS (Absolute), Relative, or SMPTE, the zero point is always at ABS 00:00:00:00 (the beginning of the audio section, just after the leader).

9-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 9, Autolocation

9.2 DEFERRED PLAY AND RECORD

To automatically enter Play mode after locating, press Play before a locate completes. To cancel while tape is moving, press Stop, Rewind, FF, or Search.

To automatically enter Record mode after locating, press Play and Record before a locate completes. To cancel while tape is moving, press Play, Stop, Rewind, FF, or Search.

9.3 PLAY-AFTER-LOCATE (AUTO PLAY)

To always enter Play mode after completing a locate, press Auto Play (its button lights). This button can be pressed at any time. To cancel, press Stop or some other transport control before the location is complete.

9.4 LOOP BETWEEN START AND END LOCATE POINTS (AUTO RETURN)

You can set up “loop points” (start and end locate points; see section 9.1), and program the M20 to automatically return to the start locate point after reaching the end locate point. This works during play or record. The start and end locate points are chosen from the possible 100 locate points in memory, and default to locations 01 and 02 respectively.

To enable Auto Return, press the Auto Return button at any point (stopped, playing, or recording) as long as the tape is before the end point. Enabling Auto Return when the tape is past the end point has no effect.

If the end point is reached while recording, the M20 will punch out before rewinding to the start point.

Turning off Auto Return while it’s returning to the start point initiates normal Rewind mode.

ALESIS M20 REFERENCE MANUAL 1.06 9-3

Autolocation, Chapter 9

9.4A SETTING LOOP START AND END POINTS

To edit the start and end locate points, follow the steps below.

Operation You press… You see…

Show start locate point Edit button followed by

Choose start locate point Up/Down buttons or

Edit start locate point Cursor Right button,

Display end locate point Auto Return button

Choose end locate point Up/Down buttons or

Edit end locate point Cursor buttons, then

the Auto Return button

number keys

then enter numbers (keypad, Up/Down buttons,) in the appropriate fields (or use Copy Tape Location)

again (toggles between start and end points)

number keys

enter numbers (keypad, Up/Down buttons, Copy Tape Location) in the appropriate fields

Display shows Start Point location Display shows new start Point location Field to be edited flashing, then replaced by your entry

Display shows End Point location

Display shows new End Point location Field to be edited flashing, then replaced by your entry

Loop Count feature: For continuous looping of a section, Auto Return and Auto Play are

both turned on. Hold Peak Clear while pressing Auto Return to temporarily display the current loop count. To preserve the tape from accidental wear, the M20 will automatically exit Auto Play mode after 100 continuous loops of Auto Return.

9.5 SET PRE-ROLL

For rehearsal or recording, it’s often important to hear a few seconds of music prior to an entry point. Setting a pre-roll time locates the tape prior to any location point by the specified amount of pre-roll (0 to 25 seconds; default is 5 seconds). Setting pre-roll = 0 causes the tape to locate to the cue point (same as disabling pre-roll).

Pre-roll also works when looping between two points.

Operation You press… You see…

Display Pre-Roll time Edit button followed by

Edit Pre-Roll time Enter time with numeric

Leave Pre-Roll Edit mode Press Edit button again Edit light goes out. Pre-

the Pre-Roll button

keypad or Up/Down buttons

Display shows existing pre-roll time Display shows new PreRoll time

Roll button light returns to its on or off status.

9-4 ALESIS M20 REFERENCE MANUAL 1.06

9.6 SET POST-ROLL

For rehearsal or recording in Auto Record mode, setting a post-roll time causes the tape to go beyond the punch-out point by the specified post-roll time prior to stopping (0 to 25 seconds; default is 5 seconds). Setting post-roll = 0 causes the tape to locate to the cue point (same as disabling post-roll).

Operation You press… You see…

Display Post-Roll time Edit button followed by

Edit Post-Roll time Enter time with numeric

End Post-Roll edit mode Press Edit button again Edit light goes out. Post-

Post-roll also affects the time when looping between two points.

Tip: If you have to do a number of takes/overdubs at the same locations, use Auto

Return and Auto Record together. Set the Loop Start point to the Punch In point, and the Loop End point to the Punch Out point. Setting a Pre-Roll and Post Roll allows the M20 to be in sync before the punch, and allow the talent to hear their cues.

the Post-Roll button

keypad or Up/Down buttons

Chapter 9, Autolocation

Display shows existing post-roll time Display shows new PostRoll time

Roll button light returns to either on or off

ALESIS M20 REFERENCE MANUAL 1.06 9-5

Autolocation, Chapter 9

9.7 FOOTSWITCH-CONTROLLED LOCATION

If the transport is playing, pressing the Locate/Play footswitch locates the transport to the Auto Return locate point, then stop or enter play, depending on the setting of the Auto Play switch (section 9.3).

Pressing the Locate/Play footswitch while the tape is locating initiates stop.

Note: If the transport is stopped, pressing the Locate/Play footswitch initiates play.

9-6 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 10

VARISPEED

Varispeed changes the sampling rate to change the audio’s pitch. This feature only applies when the Clock Source is set to INT (Internal). Pitch mode is automatically set to Fixed whenever the M20 is being controlled by an external unit (for example, when SMPTE Chase is on).

The varispeed range is -300 through +100 cents (-15.91% to +5.95%) at a base 48 kHz sample rate and -200 through +200 cents (-10.91% to +12.25%) at a base 44.1 kHz sample rate. This allows a total sample rate range from approximately 39.289 kHz (-200 cents @ 44.1 kHz) to

50.854 kHz (+100 @ 48 kHz). Note that pitch changes affect all slave machines. Varispeed settings are retained in memory.

Operation You press… You see…

Enter Varispeed Edit mode

Set varispeed amount Enter amount with

Enable varispeed Press Pitch Mode button

Disable varispeed Press Pitch Mode button

Varispeed button Display shows amount of

varispeed change in cents and as a percentage

Display shows amount of numeric keypad or Up/Down buttons. When Vari is set to 000, Up/Down buttons select + or - before entering a number. If Vari is any other value, Up/Down increments/decrements the value.

until…

varispeed change

Vari in the pitch block

Fixed in the pitch block

In Varispeed mode, the time counters will not show the true elapsed (i.e., “clock on the wall”) time intervals.

Synchronization warning: Any time code being sent from the M20 will be sped up or slowed down when using Varispeed mode. This may cause synchronization problems in other equipment that is slaved to the M20. If you’re using SMPTE time code synchronization anywhere in your project, use varispeed with great caution.

ALESIS M20 REFERENCE MANUAL 1.06 10-1

Varispeed, Chapter 10

10-2 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 11

SMPTE, SYNC, AND OFFSET

FUNCTIONS

The buttons described in sections 11.1 through 11.5 are located under the main (right) display.

The buttons described in sections 11.6 through 11.9 are part of the Edit button group toward the M20’s lower left under the meter display and track arming buttons.

11.1 CLOCK SOURCE

This switch cycles through up to seven different clock selections.

• Internal (M20 internal clock)

• Video

• ADAT (if the unit is seeing a valid 9-pin ADAT Sync In connection)

• Word Clock

• I/O card (if one is installed in the Expansion Slot on the back panel)

• SMPTE

• Optical

Note: Setting the clock to Int on an ADAT slave M20 automatically selects its ADAT clock option. Also, selecting any source other than Internal when no valid clock is available automatically switches the M20 to internal clock, and flashes the currently selected clock indicator until the M20 senses a valid clock.

ALESIS M20 REFERENCE MANUAL 1.06 11-1

SMPTE, Sync, and Offset, Chapter 11

11.2 SMPTE RATE

SMPTE Rate cycles through six different SMPTE frame rates and types; this affects both SMPTE time code input and M20 SMPTE time code output. It is not possible to receive and transmit different frame rates simultaneously.

• 24 film

• 25 European (PAL) video

• 29.97 NTSC color video

• 29.97 Drop NTSC color video drop frame

• 30 American monochrome video, most audio applications

• 30 Drop American monochrome video drop frame

When receiving SMPTE time code, input and output frame rates are set to the incoming frame rate (displayed by the SMPTE frame rate indicator). 29.97 and 30 frames/sec are not identified automatically due to possible source speed variations, and must be set manually.

Frame rates when receiving video are adjusted automatically, as follows:

Clock Source is set to…

Video NTSC can select 29.97 or 29.97 drop frame Video PAL/SECAM is set to 25 fps

Incoming video is…

11.3 TIME CODE SOURCE

This switch selects either:

• The time code generated by the M20, with the start time set in the Internal Gen pages (Internal mode)

• An outside SMPTE source (External mode)

11.3A INTERNAL

Time code generated by the M20 appears at the Time Code Output jack. The internal generator generates SMPTE/EBU time code according to several parameters that are set in Int Gen Edit mode. Code may be generated only when the transport is moving, or when it is stopped. The numbers of the time code being generated may be referenced to tape in several ways, or set independently by the user.

TC Input button: In any case, the internal generator of the M20 will only start issuing

code when the white TC Input button, below the TC Track meter and Record Arming button, is turned on. As long as the TC Source is set to Internal, the internal

generator (NOT the rear panel Time Code In jack) is considered the “input” source for this button.

Frame rate…

When the TC track is not in Input mode and is playing back, the time code output comes

from the TC track on the tape, if there is time code printed.

11-2 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 11, SMPTE, Sync and Offset

For example, Int Gen always generates time code when the Internal Generator TC Start Ref parameter is set to User Set, Free Run, and the TC Input button is lit. Setting this parameter to ABS Time generates time code only if there is a valid, ADAT-formatted tape in the transport. Setting this parameter to TC Track generates time code only if there is valid time code recorded on the TC track of the tape.

With the Time Code track in Input mode, the time code start point and internal generator functions vary, as shown below.

TC Source Mode

External N/A Disabled N/A Input time code passes through

Internal ABS

Internal User Set Enabled Run immediately (in

Internal TC track Enabled Run immediately (in

Int Gen Start Ref

Time

Caution: If the TC track is put into record when the internal generator is disabled and the TC track is in Input mode, the TC track will record no time code and will erase any previous TC track time code.

Intern Gen status

Enabled Run immediately (in

Internal Gen will… How Time Code Starts

Free Run mode) or when tape is moving (in Play/Rec mode)

to the output Time code starts from the ABS time + internal generator ABS offset

Time code starts from the specified time

Internal generator time code starts from the TC track.

11.4 CHASE REFERENCE

Chase Reference chooses between two chase (synchronization) reference options. The tape time code playback mode automatically follows the incoming time code frame rate.

• With ABS Time mode, the M20 will chase incoming SMPTE based on its absolute time reference (the standard ADAT-format time code).

• With Tape TC mode, the time code track recorded on tape provides the reference for locking to incoming SMPTE. If there is no time code on tape, the tape will not chase incoming SMPTE.

Note: In both cases, when synchronizing to optical or word clocks, the time code must be synchronous to the sample rate (this will always be the case if synchronizing to absolute time; if synchronizing to tape time code, the TC track must be synchronous to the clock). For the M20 to lock, you must also make sure that the incoming time code is synchronous to the incoming word clock.

ALESIS M20 REFERENCE MANUAL 1.06 11-3

SMPTE, Sync, and Offset, Chapter 11

11.5 REFERENCE COUNTER

This button cycles through the reference counter display options (this display is above the Reference Counter button). The selected display option (just below the display digits) shows one of the following times:

• SMPTE In Incoming time code

• Locate Pt 2-digit locate address shown in the Locate Pt block

• Tape TC TC track time code

• Int Generator Internal generator time code

• Offset Tape or chase offset

11.6 SMPTE CHASE

This switch toggles Chase mode on and off. When enabled (Chase LED on), the M20 chases (follows) any external SMPTE Time Code input.

To display or edit the chase parameters, press the Edit button then the SMPTE Chase button. There are 4 pages of parameters. Pressing the SMPTE Chase button cycles through the 4 pages.

11.6A SET SMPTE OFFSET VALUE (PAGE 1)

You may specify a SMPTE offset (up to ±24 hours) that is added to or subtracted from the Time Code reference (either ABS TIME or TAPE Time Code). Example: If you add an offset of 00:01:00:00 (1 minute), the M20 interprets an incoming SMPTE time of 00:05:30:00 as 00:06:30:00, and the SMPTE Tape Counter display shows 00:06:30:00.

Note: To edit the Samples field, select the Subframes field, then press the Cursor Right button (for more on subframes, see section 3.3).

Operation You press… You see…

Select field to edit Left/Right Arrow

buttons to scroll to

desired field Change sign (+ to add offset, - to subtract) Change numeric field value

Exit SMPTE Offset setup Edit button or any other

Up/Down buttons Flashing sign changes

Enter two-digit number

from keypad (leading

zeroes must be entered)

or use Up/Down buttons

Edit Group button

Selected field flashes

from + to Field to be edited flashes, then is replaced by your entry

Display leaves SMPTE Offset function

11-4 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 11, SMPTE, Sync and Offset

11.6B SET SMPTE CHASE MODE (PAGE 2)

There are two chase modes: Frame-Lock (default) and Lock/Release (i.e., Lock and Release to clock). Chase must be enabled.

The Down Arrow button or keypad button 0 selects Frame-Lock. With Frame-Lock mode, the M20 will relocate to incoming time code if it does not match the current tape location.

The Up Arrow button or any keypad button greater than 0 selects Lock/Release. In Lock/Release, the M20 references the incoming time code location to establish a lock. Once locked, it ignores the time code data and follows the selected external clock source to maintain lock.

Definition of Lock/Release mode: In Lock/Release, if the incoming time code stops for

more than the flywheel amount (section 11.6c), is running but not advancing its frame numbers, starts counting frames backwards, or begins to advance at a nonplay speed, the M20 will stop playing and attempt to chase to the time code location. If the time code is advancing forward but has a discontinuity, the M20 will continue to play without attempting to chase to the new time code location. Lock and release mode is a more “forgiving” mode in difficult time code applications where the master code has dropouts or jumps from one type to another.

11.6C SET FLYWHEEL DURATION (PAGE 3)

This parameter selects the maximum number of invalid or missing time code frames that will be ignored (up to 150 maximum). In Frame-Lock chase mode, the M20 keeps playing for the flywheel time as if valid time code was present, then chases when valid time code data reappears. In Lock/Release chase mode, flywheel sets the amount of time that the M20 will continue to play in the absence of incoming time code before stopping the tape.

Use the Up/Down buttons, or enter a 3-digit number with the keypad (leading zeroes must be entered).

11.6D PARK AHEAD (PAGE 4)

The M20 can park tape ahead of the last valid time code input, up to 59:29 (seconds/frames). Default is 00:00 (tape does not park ahead). The Park Ahead parameter is available to make lockup times shorter in situations where the master time code source drops out or drifts for a few seconds as it stops and starts (for example, when a VTR disengages).

Operation You press… You see…

Select field to edit Left/Right Arrow

buttons to scroll to

desired field Change numeric field value

Exit Park Ahead setup Edit button or any other

Enter two-digit number

from keypad (leading

zeroes must be entered)

or use Up/Down buttons

Edit Group button

Cursor under selected field

Your entry replaces current field value

Display leaves Park Ahead function

ALESIS M20 REFERENCE MANUAL 1.06 11-5

SMPTE, Sync, and Offset, Chapter 11

11.7 INTERNAL GENERATOR

This button turns the internal time code generator on and off (Time Code Source must be set to Internal; see section 11.3). Setting the Time Code Source to External automatically turns off the Internal Gen function. If you press Int Gen when TC Source is External, the display will read “TC Source not internal”. If the TC Source is Internal, then the generator may be turned on or off.

TC Input button: In any case, the internal generator of the M20 will only start issuing

code when the white TC Input button, below the TC Track meter and Record Arming button, is enabled.

If chase is enabled, Time Code Source = Internal and the Time Code Track is in Input mode, then the time code output will be the Chase reference (ABS TIME or TAPE TC) plus any SMPTE Offset.

If chase is disabled, Time Code Source = Internal and the Time Code Track is in Input mode, then the time code output is selected on the following pages.

Note: If the TC Source is Internal, the time code track is in record, and the internal generator is off, then any previously recorded time code will be erased.

11.7A GENERATOR MODE (PAGE 1)

In Free Run mode, enabling/disabling Internal Gen respectively starts/stops the internal generator. In Play/Rec mode, enabling Internal Gen causes the internal generator to run only while playing or recording. Disabling Internal Gen always stops the internal generator.

The Down button or keypad button 0 selects Play/Rec (default).

The Up button or any keypad button greater than 0 selects Free Run.

11-6 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 11, SMPTE, Sync and Offset

11.7B TIME CODE START REFERENCE (PAGE 2)

This page sets the internal generator’s starting reference. Use the Up/Down buttons to select one of three options, or use the keypad numbers given below.

• With ABS Time (keypad 0), the internal generator’s start address is the current ABS address plus any ABS offset (set on Page 3). The generator outputs time code based on the M20’s absolute time track. Note: For time code to appear at the rear panel time code output,

the time code track must be input-enabled, the generator must be running, and a formatted tape must be loaded.

• With TC Track (keypad 1), the current TC track time code becomes the internal generator’s start address. The generator will continue generating the same format code as on the time code track when the input is enabled and the generator is running. If no code exists on tape, no time code will be output or recorded; the display temporarily shows “TC Reference not present” if you try to turn Int Gen on.

• With User Set (any keypad number >1), the generator will output time code that is synchronous to the absolute time, but starting at an arbitrary address as defined in the next page. The time code will only be generated while the time code track is inputenabled. The generator retains the address at which it was stopped, and continues when re-started. In other words, whenever the generator is running with a User Set TC Start reference, it updates the User Set Start number.

11.7C ABS/START OFFSET (PAGE 3)

This page shows “ABS” if Page 2 is set to ABS, and “START” if Page 2 is set to User Set.

If the Internal Generator is set to ABS, you can enter an offset for the time code output compared to the ABS time.

If the Internal Generator is set to User Set, you can enter a new generator start time. The display shows the current generator location when last stopped in User Set mode.

If the generator is running, this page will show the previous start value, but the cursor will not be displayed as the start time cannot be edited while the generator is running.

Here’s how to edit the ABS/Start offset value:

Operation You press… You see…

Select field to edit Left/Right Arrow

buttons to scroll to

desired field Change numeric field value

Exit ABS/Start setup Edit button or any other

Enter two-digit number

from keypad (leading

zeroes must be entered)

or use Up/Down buttons

Edit Group button

Cursor under selected field

Your entry replaces current field value

Display leaves ABS/Start function

ALESIS M20 REFERENCE MANUAL 1.06 11-7

SMPTE, Sync, and Offset, Chapter 11

11.7D USER BITS (PAGE 4, OR PAGE 3 IF THE PAGE 2 VALUE

TC TRACK)

This page allows entering 8 hex characters (0 - F) into the user bits of the SMPTE time code. These bits are used to identify reels, projects etc. and may be displayed by an appropriate SMPTE time code reader.

Operation You press… You see…

Select digit to edit Left/Right Arrow

Change digit value Use Up/Down buttons

Exit User Bits setup Edit button or any other

buttons to scroll to desired digit

or enter digit from keypad (the 1 key cycles through 1-A-B-C, the 2 key cycles through 2-DE-F)

Edit Group button

Cursor under selected digit

Your entry replaces current digit

Display leaves User Bits function

11.8 TAPE OFFSET

This function is intended for offsetting individual M20s or ADATs from each other

within a multi-ADAT system only, not for setting an offset from an external SMPTE time code master. For setting a SMPTE offset see section 11.6a.

This offsets (shifts in time) the master ADAT (ID1) compared to the slave ADATs, or individual slaves compared to the master. The offset can be referenced to ABS time code or between two locate points.

An offset-enabled slave is offset by the specified amount from the master machine. With offset enabled on the master, it is offset by the specified amount from all slave units (i.e., all slaves are offset by the negative amount compared to the master unit).

In Edit Tape Offset mode, the Up/Down buttons choose between (ABS) Time Code and Location.

If Offset Mode = Time code, the reference counter displays the offset amount (up to ±24 hours) in hours, minutes, seconds, frames, and subframes. (To edit the Samples field, select the Subframes field, then press the Cursor Right button.)

11-8 ALESIS M20 REFERENCE MANUAL 1.06

Chapter 11, SMPTE, Sync and Offset

Operation You press… You see…

Select Time Code field to edit

Change sign (+ to add offset, - to subtract) Change numeric field value

Exit Tape Offset setup Edit button or any other

If Offset mode = Locate, the time code counter displays the two locate points that define the offset as “aa to bb,” where aa and bb are locate numbers ranging from 00 through 99. They both default to 00 on power-on, since identical locate points result in no offset. Setting Locate aa before or after Locate bb creates a positive or negative offset, respectively (offset = locate bb - locate aa). To see the actual offset time, change the mode to Time Code and the time code display will show the offset amount.

Operation You press… You see…

Select 1st Locate point Right Arrow button to

Change numeric field value

Select 2nd Locate point Right Arrow button to

Change numeric field value

(Optional) check time of offset Change offset readout to Time Code

Exit Tape Offset setup Edit button or any other

Left/Right Arrow

buttons to scroll to

desired field

Up/Down buttons Flashing sign changes

Enter two-digit number

from keypad (leading

zeroes must be entered)

or use Up/Down buttons

Edit Group button

scroll to Locate 1 field

Enter two-digit number

from keypad (leading

zeroes must be entered)

or use Up/Down buttons

scroll to Locate 2 field

Enter two-digit number

from keypad (leading

zeroes must be entered)

or use Up/Down buttons

Tape Offset button Cursor jumps to Offset

No (Down Arrow)

button

Edit Group button

Selected field flashes

from (+) to (-) Field to be edited flashes, then is replaced by your entry, cursor goes to next field to the right Display leaves Tape Offset function

Selected field flashes

Field to be edited flashes, then is replaced by your entry

Selected field flashes

Field to be edited flashes, then is replaced by your entry

mode line Offset mode changes to Time Code, display shows offset time in H:M:S:F:SF Display leaves Tape Offset function

Note: ABS has priority over Locate settings. In other words, if you choose a Locate offset, then go to the ABS display to see the time offset, then change the ABS setting, the machine will follow the ABS setting.

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SMPTE, Sync, and Offset, Chapter 11

11.9 TRACK DELAY

Track Delay allows offsetting individual tracks in time. Example: Delaying a snare part slightly compared to other drums can give a more “laid back” feel.

Maximum delay time is 170.0 ms at 48 kHz and 185.0 ms at 44.1 kHz, adjustable in 0.1 ms steps (0 through 8160 samples). The delay time displayed is accurate only while playing at normal pitch (48 kHz or 44.1 kHz), and will not compensate for pitch changes or external clock variations.

To change delay for individual tracks:

Operation You press… You see…

Select track to edit Track Delay button to

Select Delay Time display (ms or samples) Change Delay Time display (ms or samples) Select Delay time for editing

Change Delay time Use Up/Down buttons

Exit Track Delay setup Edit button or any other

Track # in Trk Delay line cycle through the 8 tracks, or press track input enable button Cursor right Cursor appears under ms

Up/Down buttons ms or smp in Trk Delay

Use Cursor Left/Right buttons to place cursor under numeric field

or enter 4-digit number (leading zeroes required)

Edit Group button

changes, cursor appears

under matching track

meter

line

Cursor parks under

rightmost digit

Your entry replaces field

to be edited, track meter

shows rough “bar graph”

of delay time

Display leaves Track

Delay function

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Chapter 11, SMPTE, Sync and Offset

To change delay for several tracks at once:

Operation You press… You see…

Select tracks to edit Press track Input Enable

button for one track to be delayed and while holding it, press Input Enable buttons for other tracks to be delayed. The All Input button selects

all tracks. Select Delay Time display (ms or samples) Change Delay Time display (ms or samples) Select Delay time for editing

Change delay time Use Up/Down buttons

Exit Track Delay setup Edit button or any other

Cursor right Cursor appears under ms

Up/Down buttons ms or smp in Trk Delay

Use Cursor Left/Right

buttons to place cursor

under numeric field

or enter 4-digit number

(leading zeroes required)

Edit Group button

Trk Delay line changes name to Group Delay

line Cursor parks under rightmost digit

Your entry replaces field to be edited, track meter shows rough “bar graph” of delay time Display leaves Track Delay function

ALESIS M20 REFERENCE MANUAL 1.06 11-11

SMPTE, Sync, and Offset, Chapter 11

11-12 ALESIS M20 REFERENCE MANUAL 1.06

MIDI FUNCTIONS

There are seven pages of MIDI functions. Pressing the MIDI button cycles through the pages in order.

12.1 MIDI DEVICE (PAGE 1)

Selects the M20’s device ID (1—127 or All) so that MIDI Machine Control systems with multiple M20s can address them separately. Selecting All means that M20s respond to all incoming MIDI messages. Default ID = 000.

Use the Up/Down buttons or number keys to enter the desired ID. To enter All, scroll past 127, or enter any number greater than 127.

12.2 MMC OUTPUT (PAGE 2)

Enables or disables the M20 from transmitting MIDI Machine Control commands from the MIDI output. Default is Off.

Use the Up/Down buttons to choose on or off.

CHAPTER 12

12.3 MTC FOLLOW GEN (PAGE 3)

Sets whether MTC (MIDI Time Code) will be generated simultaneously with SMPTE. Default is Off.

Use the Up/Down buttons to choose on or off.

12.4 SEND SYSEX DUMP? (PAGE 4)

Sends the current setup information (as MIDI system exclusive data) via the MIDI Out port. Setup information includes all data currently in the unit such as locate point names and addresses, track delays, tape offsets etc. Sending a Sysex dump to the input of another M20 gives it the same setup as the transmitting M20. This data can also be saved to a storage device (Alesis Data Disk, sequencer program, etc.) to store specific setups for later recall.

Action to perform… Display shows…

With Page 4 selected, press Yes Sending Sysex Dump Wait for dump to end Initial Page 4 display

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MIDI Functions, Chapter 12

12.5 RECEIVE SYSEX DUMP? (PAGE 5)

Receives setup information (as MIDI system exclusive data) via the MIDI In port. This could come from another M20 or a data storage device.

Action to perform… Display shows…

With Page 5 selected, press Yes Rdy to Recv Sysex Dump Initiate dump from the transmitting device Wait for dump to end Sysex Receive Complete briefly when dump is

Note: The current setup does not update unless a complete dump is received. If the reception is interrupted, the display shows Received Incomplete Dump until any other button is pressed.

Receiving Sysex Dump

complete

12.6 SEND SOFTWARE? (PAGE 6)

This function sends the M20’s current operating system software via the MIDI Out port, typically to another M20 to update its operating system, or to a data storage device for backup. The tape must be ejected prior to sending software. This operation will take

approximately 12 minutes.

Action to perform… Display shows…

With Page 6 selected, press Yes Press ENTER to confirm or NO to exit Initiate send Press Enter Wait for software to be transmitted Percentage of send completed Exit by pressing any edit or keypad button

Note: To cancel a transmission, hold the Stop button and press Eject. Be careful ó cancelling a send may leave a receiving unit non-functional.

Whatever is associated with button you pushed

12.7 LOAD SOFTWARE? (PAGE 7)

This page allows updating the M20 operating system via data received at the MIDI In port, typically from another M20, a data storage device, or computer sequencer. The tape must be ejected prior to loading software. This operation will take from 6 to 12 minutes depending

on the sysex file source (e.g. M20, computer sequencer, etc.).

Action to perform… Display shows…

With Page 7 selected, press Yes Code seg will be erased. Press ENTER to

confirm or press NO to exit. Erase existing code by pressing Enter Update M20 software Rdy To Receive Software Initiate send at transmitting device (if using an M20, see section 12.6) Wait for load operation to end (approximately 6 minutes from the Alesis sourced MIDI file, 12 minutes from another M20).

Erasing code block…

Please Wait — Updating

Software Updated. After 4 seconds, the

message changes to Restarting … The

machine automatically restarts.

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Chapter 12, MIDI Functions

Before loading new software into your M20, always save a “backup” of the existing

software in the M20 to your computer sequencer or data storage device. This will safeguard against any mishaps that could occur during the software loading process (i.e. corrupted MIDI file, equipment failure, etc.).

WARNING: If the M20 loads an incomplete update or incorrect data, the main display will show an error message. If a software load attempt fails, it is necessary to properly load the software before using the M20. The M20 will be nonfunctional until the operating system is successfully loaded. You will need to power-cycle the M20 (turn the unit off then on again) after an incomplete load. When the M20 restarts, the main display will prompt you to erase the software again. Erase the old software and re-send the updated M20 software.

For more on M20 software, see Tutorial 6 in Chapter 15.

ALESIS M20 REFERENCE MANUAL 1.06 12-3

MIDI Functions, Chapter 12

12-4 ALESIS M20 REFERENCE MANUAL 1.06

There are 22 pages of Utility functions. Pressing the Utility button cycles through the pages in order.

Shortcut: To jump directly to a particular page, hold Utility down and enter the page

number form the keypad, using leading zeroes to access pages 01-09.

13.1 DIGITAL OUT (PAGE 1)

Selects the digital output format and resolution for tapes formatted in 20-bit mode (there is no choice of digital output with 16-bit tapes).

Procedure: Use the Up/Down buttons (or keypad buttons 0-4) to choose among the following:

20-bit (default). All 20 bits of audio are available at the optical and I/O card outputs.

CHAPTER 13

UTILITY MENU

16-bit dithered. The digital audio optical output from a 20-bit tape or digital input source is dithered down (using the 4 least-significant bits of the 20-bit signal) to a 16-bit output. This is the preferred 16-bit mode.

16-bit. This simply truncates the 4 least-significant bits from a 20-bit tape or digital input source.

Digital Thru. The digital audio input from an optical or I/O card source goes directly to the optical or I/O card output. The source word length is unchanged.

13.2 ONLINE SOURCE (PAGE 2)

Sets the control source when Online mode (section 13.2a) is enabled.

Procedure: Use the Up/Down buttons (or keypad buttons 0-3) to choose among the following:

ADAT (default). Receives control commands from the ADAT 9-pin Sync In connector.

MIDI. Receives MIDI Machine Control commands from the MIDI In port.

RS-422 (Software version 2.0 and above only). Receives commands from the RS-422 port.

Note: MIDI does not need to be selected to receive Sysex and software dumps (sections 12.5 and 12.7).

13.2A ONLINE BUTTON

The Online button determines whether the M20 will respond to control commands from the source specified in Online Source (section 13.2). Regardless of the Online status and source, the machine will continue to monitor and pass commands back and forth on its sync port. Online cannot be switched off on a lone-M20 system.

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Utility Menu, Chapter 13

When enabled (Online = LED lit), the machine responds to commands from the selected Online Source. Local control may be allowed or ignored, as set on Utility Page 3 (section

13.3).

When disabled (Offline = LED off), the machine ignores commands from the selected Online Source.

Note: Certain user parameters are not editable when a machine is online, and only some parameters may be edited regardless of online status. The relevant parameters are duplicated and stored in 2 groups. One group is used when the machine is online, and the other when the machine is offline.

13.2B INDEPENDENT SLAVE MODE

A slave machine will always respond to front panel transport button presses (subject to the local/remote setting on Utility Page 3, section 13.3), regardless of whether it is online or offline.

13.3 ONLINE CONTROL (PAGE 3)

Chooses whether local control is also available if a remote control source is selected.

Procedure: Use the Up/Down buttons (or keypad buttons 0 and 1) to choose between the following:

Local/Remote (default). Receives control commands from front panel and LRC as well as the selected online source.

Remote. Allows control only from the selected remote source. There is no local control from any button on the front panel other than to disable the Online function.

13.4 ONE-BUTTON RECORD (PAGE 4)

With One-Button Record off, it is necessary to press both Play and Record to initiate recording. With One-Button Record on, simply pressing Record initiates recording.

Procedure: Use the Up/Down buttons to turn One-Button Record on or off.

13.5 INPUT MONITOR (PAGE 5)

Determines whether the analog input is monitored directly from the inputs or through the A/D and D/A converters.

Procedure: Use the Up/Down buttons to choose between the following:

ADC/DAC (default). The analog input is monitored after going through the A/D and D/A converters. Monitoring through the converters adds a very slight bit of latency (approximately 600 µseconds), but accurately reflects any changes to the signal that occur from the conversion process.

Direct. The analog input is monitored directly from the inputs without going through digital conversion.

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Chapter 13, Utility Menu

13.6 CROSSFADE TIME (PAGE 6)

Sets the crossfade time when the M20 transitions from Play to Record, or Record to Play. With a 48 kHz sample rate, the crossfade values range from 5.4 ms - 1.365 seconds. At 44.1 kHz, the crossfade values range from 5.8 ms - 1.486 seconds. Default is 10 ms.

Procedure: Use the Up/Down buttons to cycle through the 32 crossfade times.

When punching into the middle of a low-frequency tone, a crossfade time that is too short may cause a click.

13.7 TIME CODE OUTPUT LEVEL (PAGE 7)

Adjusts the time code peak-to-peak output level from 0.1V to 3.0V in 0.1V increments.

Procedure: Use the Up/Down buttons to increment/decrement in 0.1V increments, or enter the two-digit number directly with the keypad. Leading zeroes must be entered (e.g., for a

0.5V output, enter 0 then 5). Default is 1.0V.

13.8 REWIND/FAST FORWARD TC OUTPUT (PAGE 8)

The M20 can output SMPTE and MTC any time the tape is moving (fast forward, cue, rewind, jog, shuttle, etc.) if this option is enabled. When off, time code is transmitted only in Play mode. Default is off.

Procedure: Use the Up/Down buttons to turn Rewind/Fast Forward Time Code Out on or off.

Turn this OFF if your system (mixer automation, computer sequencer etc.) acts strangely

when you fast wind the M20; it probably can’t understand the fast bursts of time code and “gets lost”.

Turn this ON for faster locating of slave machines in code-only master systems.

13.9 UNTHREAD TIMEOUT (PAGE 9)

Sets how long the transport must be idle (from 1 to 20 minutes) before the tape is unthreaded from the head drum. Shorter times trade off less head and tape wear for less convenience, as it takes slightly longer to go into Play or Record mode from stop if the tape is unthreaded. Default is 4 minutes.

Procedure: Use the Up/Down buttons to increment/decrement in 1-minute increments, or enter the two-digit number directly with the keypad. Leading zeroes must be entered (e.g., for a 3 minute timeout, enter 0 then 3). If both numbers are not entered within 3 seconds, the display reverts to the previous setting.

ALESIS M20 REFERENCE MANUAL 1.06 13-3

Utility Menu, Chapter 13

13.10 SEARCH ENABLE (PAGE 10)

Determines how to enable Search mode, where the Jog/Shuttle wheel is active.

Procedure: Use the Up/Down buttons to choose between the following:

Normal (default). Moving the Jog/Shuttle wheel or pressing the Search button (it lights solid) automatically enables Search mode.

Button. You must press the Search button to enable the Jog/Shuttle wheel.

13.11 LOCATE BEFORE PLAY (PAGE 11)

When On (default), the master M20 will not play until all ADAT slaves have located to the master’s tape location. When Off, initiating Play causes the master M20 to play immediately. Any ADAT slaves that are not at the master tape’s location “catch up” while the master plays. This parameter is relevant only if ADAT slaves are online with tapes inserted.

Procedure: Use the Up/Down buttons to choose between On and Off.

13.12 MUTE UNTIL LOCK (PAGE 12)

This allows all ADAT tracks in a multi-machine system to be heard simultaneously when all machines in the system are locked. When On, M20 masters and slaves will mute their audio outputs until all M20s in the system have locked. When Off (default), audio will be output from individual M20s as each one locks, prior to all machines establishing a lock.

13.13 DYNAMIC PUNCH (PAGE 13)

When On and Record mode is pending (section 8.6a), pressing any track record-enable button toggles between recording and playback. When Off, punching cannot be accomplished on a per-track basis using the record enable buttons. All tracks must be armed before record mode is entered.

Procedure: Use the Up/Down buttons to choose between On and Off.

13.14 TRACK GROUPS (PAGE 14)

This feature applies only if the M20 is connected to an optional CADI remote control unit. When Off, CADI Track Groups are ignored (i.e. no Track Groups can be recalled from the CADI). This prevents accidental group recording or erasing when using a CADI. When On, CADI Track Groups affect the M20s controlled by the CADI and can therefore be recalled.

13.15 SAVE DATA TO TAPE? (PAGE 15)

Saves the Table of Contents data (TOC) such as location points and names, tape offsets, track delays, etc. in a BRC-compatible format to the tape’s Data section.

Procedure: Press Yes to save data (the No key has no effect). The tape rewinds immediately to the beginning while the display shows Preparing to Save. The display then shows Saving Tape Data. After saving, (approximately 2 minutes) the screen reverts to Save Data to Tape.

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Chapter 13, Utility Menu

13.16 LOAD DATA FROM TAPE? (PAGE 16)

Loads the Table of Contents data from tape into the M20.

Procedure: Press Yes to load data (the No key has no effect). The tape rewinds immediately to the lead and data sections while the display shows Preparing to Load. The display then shows Loading Tape Data. After loading, the screen reverts to Load Data from Tape.

13.17 TAPE TYPE (PAGE 17)

Shows the length of an inserted tape (ST60, 120, 160, or 180) and the PAL equivalent (SE90, 180, 240, 260). If no tape is inserted, the display shows Type Unknown.

This screen is display-only. There are no adjustable parameters because the M20 automatically calculates the tape length when each tape is inserted (i.e. “Calibrating...Standby”).

13.18 ID STATUS (PAGE 18)

Shows the M20 device ID number. If the M20 is a master (ID 01), the display will also indicate the number of M20s slaved to the master (up to 15).

This screen is display-only. There are no adjustable parameters.

13.19 USER BITS (PAGE 19)

This page allows viewing user bits of the tape time code track, incoming SMPTE, or internal generator.

When the Time Code Track plays back, the display will be continually updated by the user bits data being read off tape.

If this page is entered while not in Play mode, it will display the last valid user bits read from tape.

If no time code user bits have ever been read from the current tape, or the tape is playing but there is no current Time Code Track, the display reads No TC Trk.

This screen is display-only. There are no adjustable parameters.

ALESIS M20 REFERENCE MANUAL 1.06 13-5

Utility Menu, Chapter 13

13.20 ERROR RATE (PAGE 20)

During playback or record, this screen shows the number of sync block errors per 14 drum revolutions (280 ms), from 0000 to 6720 (maximum number of errors possible). In any mode other than Play or Record, the display reads ----. Sync block errors are normally 100% corrected by the ADAT’s error correction circuitry, but this display acts as a kind of early warning system. Errors of a properly functioning M20 and tape typically fall in the 00000008 range. All errors are corrected unless the red ERROR indicator flashes in the main display between the Tape Counter and the Reference Counter; this typically happens when sync block errors are in the 25-100 range or above. Errors in the hundreds or thousands indicate severe problems with the tape or with the heads.

If the error rate increases significantly during the course of working with a tape, check performance with a benchmark or known good tape to see if the tape itself or dirty heads are at fault. If the tape is dropping out, clone the tape immediately to another M20. If the heads are dirty, get them cleaned by a knowledgable technician, or as a temporary fix use an approved dry cleaning tape only.

This screen is display-only. There are no adjustable parameters.

13.21 FRONT PANEL SOFTWARE VERSION (PAGE 21)

This screen shows the current front panel software version. If you need to call Alesis tech support, make a note of this number before calling.

This screen is display-only. There are no adjustable parameters.

13.22 SOFTWARE VERSION (PAGE 22)

Displays the version and date of the M20’s operating system software. If you need to call Alesis tech support, make a note of this data before calling.

This screen is display-only. There are no adjustable parameters.

13-6 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 14

THE LRC REMOTE CONTROL

The M20 hand-held LRC remote provides the following functions:

• Transport functions: Rewind, Fast Forward, Stop, Play and Record.

• Autolocation functions: Locate 1, Locate 2, Locate 3, Locate 4, Set Locate and Auto

Loop

• Track functions: Auto Record and Rehearse.

These functions are the same as can be accessed from the front panel controls.

The Auto Loop button, which does not exist on the M20 front panel, toggles both Auto Play and Auto Return functions on and off simultaneously with one button press.

Note: To enable the Auto Play function by itself without the Auto Return function (i.e. without looping), initiate a deferred play with the Play button ó that is, press any of the Locate 1 - Locate 4 buttons, followed by the Play button.

To use the LRC, plug it into the Locate/Play/LRC Remote jack. If connected to the master M20 in a multiple ADAT system, the LRC can control the entire chain of ADATs.

ALESIS M20 REFERENCE MANUAL 1.06 14-1

LRC Remote Control, Chapter 14

14-2 ALESIS M20 REFERENCE MANUAL 1.06

CHAPTER 15

TUTORIALS AND APPLICATIONS

This chapter gives guidance for entire procedures, assuming a basic familiarity with how the controls and menus work from previous chapters.

TUTORIAL 1: MULTIPLE M20 OPERATION

VERVIEW

Because the M20 is ADAT-compatible, it can work together with up to 16 other ADATfamily machines to provide a total of 128 tracks.

ADAT machines have a sync bus that provides timing information and commands for all ADATs in a system. When linking multiple ADATs together, the first machine in the chain is the “master,” and the rest are “slaves.” Each slave locks to the master and synchronizes to the master machine’s time reference.

Using the 8-channel ADAT Optical Interface, you can also bounce tracks between machines in the digital realm. The result is a perfect copy (ideal for safety backups and archives) that is synchronized to the original with single-sample accuracy.

SYNCHRONIZING MACHINES

Synchronization requires a dual male, 9-pin D connector cable for each slave to be synchronized. Use only Alesis cables, which are available in three different lengths: 8", 30", and 30'. Other cables may cause erratic sync performance.

To connect the bus (power must be off), patch one 9-pin D connector cable from the master sync out to the slave sync in. A slave in a multiple machine system will automatically detect a master and enter slave mode. With more slaves, connect the slave 2 sync out to the slave 3 sync in, slave 3 sync out to slave 4 sync in, etc.

Power on the machines from first to last, with the CADI remote control (if present) powered on after all of the ADATs.

After connecting multiple M20s and/or ADATS together and turning them on, the master’s display will show “ ID 1” (identifying itself as the number 1 machine in the system). The second machine will display ID 2, the third ID 3, and so on. The ID order is automatically assigned according to how the cables are hooked up.

If a slave does not display an ID number on power-up, then it does not see anything connected to the Sync In jack. Check the cables and connections.

To check a machine’s ID, go to Utility page 18.

AUTOMATIC ID RENUMBERING

Machines in a multiple ADAT system will renumber their IDs if more M20s or ADATs are connected later. Example: Suppose in a 3-ADAT system that machine 1 is the master, and machines 2 and 3 are slaves. If you turn on only machines 2 and 3, machine 1 will not be

ALESIS M20 REFERENCE MANUAL 1.06 15-1

Tutorials and Applications, Chapter 15

active, so machine 2 decides it’s the master (ID 1) and machine 3 the only slave (ID 2). If you then turn on machine 1, the machines will renumber themselves so that machine 1 becomes the master (ID 1), and machines 2 and 3 become the slaves (ID 2 and 3, respectively).

Sync signals cannot pass through a machine that is turned off. For example, if machines 1 and 3 are turned on but machine 2 is turned off, machine 3 will not slave to machine 1 because the sync signal cannot pass through machine 2.

MASTER/SLAVE INTERACTION

Pressing any of the Transport, Auto Rec, Auto Input, Pitch, All Input, or Locate buttons automatically triggers the same functions on the slave machine(s).

To minimize confusion, Alesis recommends initiating all operations from the master, including transport control functions. When you press Play on the master, the slave(s) will locate to the same time code point and begin playing once sync is achieved.

Pressing Eject on the master ejects all slaves’ tapes as well. To eject only the master’s tape, press and hold Peak Clear, then press Eject on the master.

When recording or punching in on the slaves, initiate recording on the master but do not record-enable any master tracks (unless, of course, you need to record tracks on the master). Any record-enabled slave tracks will go into record, while the master will simply play. This is why record enable is an independent function for each slave.

There are two other functions where the slave(s) act independently:

• Formatting is initiated independently on each slave, however, simultaneous formatting on all slaves is possible.

• Digital Input is independent for the slave(s) as you may want to record via the analog inputs on some machines and the digital inputs on others.

ACHIEVING LOCK

In a multiple-ADAT system, the slaves will “chase” the master (the M20’s Chase indicator lights) and can only enter record once they are locked. Audio will not appear at an ADAT’s outputs until it is locked, as shown by a lit Locked indicator. For the fastest chase-lock performance in a multi-ADAT system, use the Locate points when possible to go to different points on the tape.

INDEPENDENT SLAVE MODE

If a slave M20 is taken offline (Online button is off), its transport can be controlled independently. Example: Press Play on the offline slave and it will play, but the other slaves and master will not respond. When the slave in placed online again, it will respond to transport commands from the master.

15-2 ALESIS M20 REFERENCE MANUAL 1.06

FORMATTING MULTIPLE TAPES

Formatting works similarly to formatting on a single ADAT, however there are some considerations unique to formatting multiple tapes. For more information on formatting, see Chapter 4.

MASTER FORMAT ENABLED, COMPLETE FORMAT

If the master’s Format indicator is on, performing a complete start-to-finish format, and the slave tape is not already formatted:

• If the slave’s Format indicator is on, the slave rewinds to the start of the tape and does a complete format along with the master.

• If the slave’s Format indicator is off, the slave rewinds to the start of the tape and plays, but the TIME counter reads “noFO” (no format) while flashing the FORMAT indicator.

If the master’s Format indicator is on, performing a complete start-to-finish format, and the slave tape is already formatted:

• If the slave’s Format indicator is on, the slave rewinds to the start of the tape and does a complete format.

• If the slave’s Format indicator is off, the slave rewinds to the start of the tape and plays in sync with the master.

Chapter 15, Tutorials and Applications

Any record-enabled channels will start recording at time 0:00:00.00.

MASTER FORMAT ENABLED, FORMAT EXTEND

If the master’s Format indicator is on, you are extending the format, and the slave tape is not formatted, the slave plays, but its Time counter reads “noFo” (no format) while flashing its Format indicator.

If the master’s Format indicator is on, you are extending the format, and the slave tape is formatted:

• If the slave’s Format indicator is on, the slave autolocates to the same time as the master, then format extension begins with the master.

• If the slave’s Format indicator is off, the slave autolocates to the same time as the master and plays or records in sync.

To properly extend the format, the master and slaves should be playing in sync (i.e., the Locked icon should be on) before punching into format record.

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Tutorials and Applications, Chapter 15

MASTER FORMAT DISABLED

If the master’s Format indicator is off, you initiate record anywhere in the tape, and the slave’s Format indicator is off:

• If the slave tape is unformatted, the slave plays, but the Time counter reads “noFo” (no format) while flashing the Format indicator.

• If the slave tape is formatted, the slave autolocates to the same time as the master and plays or records in sync.

To properly punch in, the master and slave should be in sync before punching. Otherwise, the master will punch in immediately, but the slaves won’t punch in until sync is achieved.

MASTER FORMAT DISABLED, FORMAT EXTEND

If the master initiates recording from the audio portion of the tape and the slave’s Format button is on:

• If the slave tape is unformatted, the slave plays, but the Time counter reads “noFo” (no format) while flashing the Format indicator.

• If the slave’s tape is formatted, the slave autolocates to the same time as the master, then format extension begins.

If the master initiates recording from the start of the tape and the slave’s Format button is on, start-to-finish formatting begins regardless of whether the slave tape is formatted or not.

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Chapter 15, Tutorials and Applications

TUTORIAL 2: MAKING DIGITAL BACKUPS

You can create safety copies of M20 tapes by copying all eight tracks to another M20 (or ADAT-compatible machine) via the digital bus.

Alesis recommends creating a backup whenever you have irreplaceable material on tape.

Synchronizing two machines together via the 9-pin sync bus allows for making sampleaccurate copies, referred to the internal time code. This is preferred. Without sync, you can simply start recording on the slave and play back from the master. This faithfully copies the audio information, but in all likelihood there will be a timing offset between the two tapes.

Here’s the procedure for creating a backup tape.

Action You do... You see...

Synchronize the master and slave

Establish digital audio connection

Load machines with tapes Insert the tape to be backed up

• To make a 20-bit backup, both machines must be Type II with tapes formatted in 20-bit mode.

• If the tape is unformatted, put the slave into Format mode (see Chapter 4). If the tape is partially

formatted, the slave tape needs to have its format extended (see section 4.5).

• For safety’s sake, write-protect the tape to be copied by breaking off (or sliding open) the tape’s write protect tab.

Return both machines to a common start point Enable optical inputs Select ADAT Optical Digital

Select digital as the Input Select source on both machines Enable all slave tracks for recording

Connect a male/male, 9-pin D connector cable between the master Sync Out and the slave Sync In Connect a fiber optic cable between the master ADAT Optical Out and the slave ADAT Optical In

into the master, and a blank or formatted tape into the slave

Press the Locate 0 button Both Time counters read 0:00:00.00

Source on both the master and slave M20 Press Input Select then press All Input Press all slave Record Enable buttons

The master becomes ID 1 and the slave ID 2 on power-up

No visible change on machine

Eject lights go off

Digital Source block shows ADAT Optical

A “D” will be displayed beneath all 8 channel meters The Record indicators for all slave tracks will flash

Be sure that the Record Enable buttons are switched off for tracks 1—8 of the master M20!

Initiate tape cloning Press both Play and Record on

the master

End backup Press Stop on the master after

backup is complete

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Both machines start, Record Enable indicators on slave machine light solid Both machines stop

Tutorials and Applications, Chapter 15

DEALING WITH DAMAGED TAPE

If a tape is in very bad condition, it may be difficult to copy it from the master to a slave. If there are so many errors that the M20 momentarily loses sync during playback, all slaves will be taken out of record automatically. In this case, put the new tape into the master, the damaged tape in the slave, and copy from the slave to the master.

MAKING A 16-BIT COPY FROM A 20-BIT MASTER

With over 100,000 ADAT 16-bit Type I machines in use, you may need to trade tapes with someone who owns an older machine. You can still with the M20 in 20-bit Type II mode, and make Type I “clones” for use in older machines. You can also use an older Type I machine as a slave to an M20, using the same procedures and hookup listed earlier in this chapter.

Alesis recommends creating 16-bit “clone” tapes using dithering, a process that provides better apparent resolution than standard 16-bit copies (however, do not add dither if the material will be re-dithered later on). The process is the same as making a standard backup, except that you select a dithered 16-bit output from the master, as described in section 13.1.

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TUTORIAL 3: RECORDING DIGITAL AUDIO FROM OTHER SOURCES

Recording digital audio onto the M20 from a source other than an ADAT-compatible device requires a digital audio interface, like the Otari UFC-24 or Kurzweil DMTi, or inserting an Alesis EC-1 AES/EBU interface into the M20’s Expansion Card slot. These convert other digital audio formats to the Alesis Optical format. The ADAT-PCR card can also output audio recorded into a hard disk editing program as ADAT Optical format-compatible signals.

When recording digital audio into the M20 from another ADAT-family device in a multiple ADAT system, the M20 recording the audio is already synchronized with the other machines because all slave machines are automatically set to External Clock mode. They follow the master precisely.

When recording digital audio from some other source, the M20 must synchronize its clock to the incoming digital audio. How this is done depends on whether you are using a single M20 or a multiple ADAT system. We will assume an ADAT Optical interface cable is carrying the incoming digital audio, perhaps from an ADAT-PCR card.

With a single M20, connect the incoming Optical Out (e.g., from the ADAT-PCR card) to the M20’s Digital In using a single fiber optic connector. Press the M20’s Clock Source button, and set its clock source to Optical. The M20 will synchronize to the clock information present in the Optical Out.

In a multiple ADAT system, you have two choices: synchronize the digital audio source to the ADAT system (as described above for a single ADAT), or sync the ADAT system to the digital audio source.

If the source does not have a clock input (i.e., it cannot sync to an external clock), you need to choose the latter option. Connect the Optical Out to the master ADAT’s Optical In, whose Optical Out already connects to the next slave, and so on. Set the master’s Clock Source to ADAT (or I/O card if using the AES/EBU interface). If no digital audio clock is detected, the master M20 will continue using its own internal clock. When the master receives digital audio (and therefore, a digital clock), the master M20 will sync to the incoming digital clock.

DIGITAL CLOCK CONSIDERATIONS

Switching between the M20’s two internal clock sample rates (48 kHz and 44.1 kHz), changes the reference used for computing tape location. Therefore, the same tape location will appear to have two different time addresses depending on the selected sample rate.

Since the M20 cannot detect an external clock’s sample rate, you need to choose the reference base the M20 should use to calculate tape position while syncing to the digital clock. Select either 48 kHz or 44.1 kHz with the Sample Rate button.

If you hear clicks in the audio after recording from a digital source, either the Clock

Source is set incorrectly, or there is some other timing problem. Most commonly, clock problems are the result of trying to use SMPTE Chase and receive digital input simultaneously, where the digital source itself is not chasing the same SMPTE or clock reference as the M20, or the SMPTE isn’t referenced to digital clock. There

must be one, and only one clock source in a multi-machine system.

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Tutorials and Applications, Chapter 15

TUTORIAL 4: COMBINING M20S AND ADATS

M20 T

The M20’s transport speed is much faster in engaged mode than the original ADAT. Because of this and other unique features, make the M20 the master (ID 1) and any ADAT(s) should be the slave(s).

When locating, the M20 will locate to a specific tape position, stop, and wait for the ADAT(s) to catch up. Therefore, until you need more than 8 tracks, don’t put any tape(s) into the slave unit(s) so that the M20 won’t have to wait for the slave(s) to locate.

RANSPORT SPEED

SAMPLE RATE VS. PITCH CONTROL

The M20’s Sample Rate function, which allows choosing between 48 kHz or 44.1 kHz sampling rates, was not directly available on the original ADAT. This function also allows selecting a digital clock for applications involving the recording of digital audio from a nonADAT source.

The M20 writes sample rate information when formatting a tape, so that it automatically knows a formatted tape’s sample rate (even though either rate may be used).

Example: When playing back a tape formatted at 48 kHz with the sample rate set to 44.1 kHz, the 44.1 indicator will flash, to indicate that you are using 44.1 kHz but it isn’t the original sample rate used when the tape was formatted. The same goes when you play back a tape formatted using 44.1 kHz with the sample rate set to 48 kHz; the 48 kHz indicator will flash.

The M20 Pitch Controls supplement the sample rate selection. With the original ADAT, you had to pitch down a tape to play back at a 44.1 kHz sample rate. If you play back a tape that was formatted on an original ADAT, it will not have any sample rate information written on it. The M20 will automatically select the 48 kHz setting. If you had been pitching-down such a tape to play at 44.1 kHz, you must press the Sample Rate button to manually change the M20’s sample rate to 44.1 kHz.

INPUT MONITORING

The original ADAT was designed so that when monitoring a track’s input signal, you heard the actual analog input ó the signal did not pass through the A/D and D/A converters. There was an advanced feature, accessed by holding Set Locate and pressing All Input, that allowed monitoring after the converters. This allowed hearing exactly how the signal would sound when played back from tape.

The M20 monitors the input signals through the converters at all times (unless overridden as described in section 8.6d). This creates a minuscule delay as the digital audio passes through the converters’ buffers. If you were to listen to both the original signal on your mixer and the tape return of the same signal coming back from the M20, the M20’s delay would cause some phase cancellation when combined with the original signal. Therefore, it is important that you either monitor the original signal or the tape’s input signal on your mixer, but not both.

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POLARITY DIFFERENCES

The original ADAT inverted the polarity of the signal being recorded on tape, then flipped polarity again before going to the output jacks. As a result, the output was the same polarity as the input, so no phase problems were possible when using a single ADAT or a multiple ADAT system.

However, neither the digital input nor the digital output was inverted. Therefore, if one transfers the ADAT’s digital audio data to a DAT machine or hard disk recording system (using the AI-1 or a similar digital interface), the audio output from the other device would likely be out of phase with the ADAT, since it probably does not invert the analog signal after its D/A converters. Although this in itself will usually not be a problem, it may cause some confusion if multiple correlated audio signals are combined from multiple sources since there is a possibility that signals could become out of phase.

To prevent this from occurring, with the M20 the polarity remains constant from the analog to digital, and back to analog, domain. Like the original ADAT, the result from one machine, or multiples of the same machine, is the same: The input to output phase is correct. However, if two cloned tapes (copied digitally either with ADATs, M20s, or both) are played back in sync on both an ADAT and an M20, the outputs of the two machines will be out of phase relative to each other. Since it does not usually serve any practical purpose to play the same signal from two different tapes with two different model machines simultaneously, this should not present a problem for you. This design improvement is only mentioned here to explain this possible situation should you happen to experience it.

Possible problem: Let’s say you had been using a multiple ADAT system and you recorded a stereo signal across two machines (a stereo drum recording on tracks 8 and 9), where there is a common element to each track (i.e. center signal). If you replace one of these machines with an M20, the result would be that the track being played back on the M20 will be out of phase from the track played on the ADAT, canceling the center signal.

Here are some possible solutions:

• Use a phase switch on your mixer (if your mixing board provides this) to invert the phase of the problem track to compensate.

• Wire your patchbay to reverse the input and output polarity of the M20s in the system, but use standard cables on the ADATs in the system. This is recommended only for studios where master tapes will be exchanged between units or sent out of house.

• Digitally bounce one of the stereo tracks to the other ADAT so that both sides play back from the same machine.

• Most importantly, plan recording sessions so that stereo tracks reside on the same physical tape in a multiple ADAT system.

Note that if you overdub over an older ADAT tape in an M20, that track will now be in phase.

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Tutorials and Applications, Chapter 15

TUTORIAL 5: SETTING UP INPUTS

The M20 offers unparalleled flexibility in terms of setting up inputs for recording: signals can come from analog sources, digital sources (ADAT optical or from optional AES/EBU cards), or a combination of the two. As a result, it is important to understand the proper procedure for selecting the right sources for the right inputs. The following gives an overview of the process; for more details, see Chapter 6.

1 If you are going to be using any digital sources, specify ADAT Optical or I/O Card using

the Digital Source button.

2 Decide which track pairs will accept analog inputs, and which will accept digital inputs.

To do this, first press the Input Select button. Each push of one of a track pair’s Track Input Enable buttons toggles between analog and digital (from the digital source selected in step 1). A small “D” or “A” indicator lights under the VU meters to show the selected input source.

3 Set up the input routing for the analog signals by pressing the Input Routing button. This

function determines which inputs go to which tracks. For more details, see section 6.4a.

4 Set up the input routing for the digital signals. Press the Input Routing button twice (or

only one more time if you are already in the analog routing page). There can be a simple one-to-one correspondence (e.g., input 1 goes to track 1, input 2 goes to track 2, etc.) or tracks can be reassigned.

5 To reassign tracks, when in the digital routing page, press the Input enable buttons for

the desired digital source tracks. When you record-enable tracks, the lowest-numbered source track will be assigned to the lowest-numbered record enabled track; the nextlowest-numbered source track will be assigned to the next lowest-numbered record enabled track; and so on.

Your inputs are now set up to record from the desired source tracks.

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TUTORIAL 6: UPDATING M20 SOFTWARE

The M20 accepts software updates via MIDI. This allows Alesis to offer improvements and changes to the operating system without requiring the unit to be professionally serviced.

The fastest way to update the software is to go to the Alesis web site (http://www.alesis.com). Go to the “Software” section, and locate the area containing M20 software updates.

Files are in Standard MIDI File format, and can be downloaded as .hqx (binhex encoded) files for Macintosh computers or as .zip (compressed) files for Windows based computers. WinZip will decode zipped files. Mac users can use Stuffit to decode binhexed files.

After downloading, decode and import the file into a MIDI sequencer or other device capable of playing back MIDI files. It should be able to handle fairly long sysex dumps.

Before plugging the MIDI cable from your MIDI sequencer to the M20 MIDI in, first check the output with a MIDI activity indicator. You want to make sure that your MIDI device is indeed capable of transmitting the data before trying to load it into the M20. Loading incomplete or corrupted data into the M20 could require a trip to the dealer if there is a problem transmitting the sysex to the M20. As a precaution, you may wish to save the existing M20 software in your unit to a MIDI file as a backup in case the downloaded version became corrupted during the download or decoding process. Once you verify that your MIDI device is sending data properly, proceed.

For example, if you import the file into Cakewalk, a dialog box appears that says “File has System Exclusive auto send banks. Send them now?” Click on yes. With Mac sequencers, you may need to press Play after importing the sequence, or use the Freeloader utility (also on the Alesis web site), to start transmitting the sysex. The software updating process will take about 6 minutes to complete.

Software updating has been tested with Cakewalk on the PC, and Cubaseand Performer on the Mac. Other programs are likely to work as well.

If you do not have access to the web or to MIDI sequencers, contact your Alesis dealer about alternate ways to update your software. A simple MIDI connection from another M20 with a new software version can update your unit in about 12 minutes.

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TUTORIAL 7: USING THE M20 WITH UNBALANCED INPUTS AND OUTPUTS

It is possible to use unbalanced signals with the M20, however you will need adapters like the following:

Note that it is probable that unbalanced lines will not have enough level to drive the M20 to full scale, and will require preamplification, or the input trimmers of your M20 must be reset to accommodate lower levels. The standard factory setting is +19 dBu = 0 dBFS (just before clipping). A mixer with a standard output of +4 dBu at 0 VU should light “-15 dB” on the M20’s meter.

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Alesis M20 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual