Alesis M1 Active Mk2 User Manual

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REFERENCE MANUAL

Alesis M1 Active Mk2 Reference Manual

ALESIS CONTACT INFORMATION

Alesis Studio Electronics, Inc.

1633 26th Street

Santa Monica, CA 90404

USA

Do not use this address for repair service.

Telephone: 800-5-ALESIS (800-525-3747)

E-Mail: support@alesis.com

Website: http://www.alesis.com

Contents/Safety Warnings
CONTENTS
Introduction	2
IMPORTANT SAFETY INSTRUCTIONS......................................................	3
Safety symbols used in this product	3
Instructions de Sécurité Importantes (French)	5
Information to the User for Class A Digital Device (FCC Part 15, Class A) 7
CE Declaration of Conformity	8
ABOUT THE M1 ACTIVE MK2 ...............................................................	9
Unpacking and Inspection	9
Inside your new speakers	10
About Nearfield monitoring	15
SPEAKER INSTALLATION....................................................................	17
Avoiding reflections in the studio	17
Stereo nearfield placement of the M1 Active Mk2	20
Connections	26
Setting the Input Level control	28
SURROUND SOUND ............................................................................	31
About surround sound	31
Center speakers in music mixes	32
Placement of the center M1 Active Mk2 speaker in the studio	33
Placement of rear surrounds	34
Mixing for discrete six channel reproduction: matched vs. specialized speakers
	37
TROUBLESHOOTING ...........................................................................	39
Troubleshooting Index	39
Maintenance	40
SPECIFICATIONS ................................................................................	42
Enclosure	42
Transducers	42
Crossover section	43
Amplifier Section	43
Acoustic Section	43
General	43
INDEX..............................................................................................	44
ALESIS LIMITED WARRANTY..............................................................	45

M1 Active Mk2 Reference Manual

Contents/Safety Warnings

INTRODUCTION

Thank you for purchasing the Alesis M1 Active Mk2 Biamplified Reference Monitors. To take full advantage of the M1 Active Mk2’s operation, and to enjoy long and trouble-free use, please read this user’s manual carefully. We value any comments you may have about this monitor system, this manual, your Alesis dealer or our factory service. Please take a minute now to fill out your warranty card and tell us what you think.

HOW TO USE THIS MANUAL

This manual is divided into the following sections describing the various features of the M1 Active Mk2. Though we recommend you take time to read through the entire manual once carefully, those having general knowledge about monitors should use the table of contents to reference specific functions.

Chapter 1: About the M1 Active Mk2. Engineering specifications and reasons why nearfield monitors have become so popular.

Chapter 2: Speaker Installation. This chapter explains how to connect the M1 Active Mk2s to a mixer or other line-level source and discusses proper speaker placement for stereo operation.

Chapter 3: Surround Sound. If you are using the M1 Active Mk2 speakers in a multichannel surround sound setup, you’ll find helpful setup and operation information here.

Chapter 4: Troubleshooting. This chapter contains troubleshooting tips and service information should problems occur.

When something important appears in the manual, an icon (like the one on the left) will appear in the left margin. This symbol indicates that this information is vital when operating the M1 Active Mk2s.


2	M1 Active Reference Manual

Contents/Safety Warnings

IMPORTANT SAFETY

INSTRUCTIONS

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.

PLEASE FOLLOW THESE PRECAUTIONS WHEN USING THIS

PRODUCT:

1. Read these instructions.

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. Do not spray any liquid cleaner onto the speakers or rear panel, as this may damage the speakers, controls or cause a dangerous condition.

7.Install in accordance with the manufacturer's instructions.

8.Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.

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 are provided for your safety. When the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

M1 Active Mk2 Reference Manual

Contents/Safety Warnings

10.Protect the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.

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

12. Use only with a cart, stand, bracket, rack, or table designed for use with professional audio or music equipment. In any installation, make sure that injury or damage will not result from cables pulling on the apparatus and its mounting. If a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.

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 product 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.

4	M1 Active Reference Manual

Contents/Safety Warnings

INSTRUCTIONS DE SÉCURITÉ IMPORTANTES (FRENCH)

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 présence d’une tension non isolée à l’intérieur de l’appareil pouvant engendrer des chocs électriques.

VEUILLEZ SUIVRE CES PRÉCAUTIONS 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 proximité de l’eau.

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 proximilé 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 reliée à la terre. Cette dernière est présente pour votre sécurité. Si le cordon secteur ne rentre pas dans la prise de courant, demandez à un électricien qualifié 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 spécifiés 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.Débranchez l’appareil lors d’un orage ou lorsqu’il n’est pas utilisé pendant longtemps.

14.Faites réparer par un personnel qualifié. Une réparation est nécessaire lorsque l’appareil a été endommagé de quelque sorte que ce soit, par exemple losrque le cordon secteur ou la prise sont endommagés, si du liquide a coulé ou des objets se sont introduits dans l’appareil, si celui-ci a été exposé à la pluie ou à l’humidité, ne fonctionne pas normalement ou est tombé.

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

16.Ce produit, utilisé 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 élevé ou à un niveau non confortable. Si vous remarquez une perte de l’ouïe ou un bourdonnement dans les oreilles, consultez un spécialiste.

M1 Active Mk2 Reference Manual

Contents/Safety Warnings

BEIM BENUTZEN DIESES PRODUKTES BEACHTEN SIE

BITTE DIE FOLGENDEN SICHERHEITSHINWEISE: (GERMAN)

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 Audiound 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.

6	M1 Active Reference Manual

Contents/Safety Warnings

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)

INTERFERENCE-CAUSING EQUIPMENT STANDARD

ICES-003 ISSUE 2

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.


M1 Active Mk2 Reference Manual	7

Contents/Safety Warnings

CE DECLARATION OF CONFORMITY

This product conforms to current applicable CE standards for safety. For a detailed description of the standards used, please see the web site Alesis.com.

8	M1 Active Reference Manual

About the M1 Active Mk2

CHAPTER 1

ABOUT THE M1 ACTIVE MK2

UNPACKING AND INSPECTION

Your M1 Active Mk2 Biamplified Reference Monitors were packed carefully at the factory, and the shipping carton was designed to protect the speakers during shipping. Please retain this container in the highly unlikely event that you need to return the speakers for servicing.

The shipping carton should contain the following items:

•This instruction manual

•M1 Actives with the same serial numbers as shown on the shipping cartons

•Two AC power cords (NEMA to CEE type)

•Alesis warranty card

•Two pieces of adhesive-backed non-skid foam

It is important to register your purchase; if you have not already

filled out your warranty card and mailed it back to Alesis, please take the time to do so now.

The M1 Active Mk2s are designed as mirror-imaged pairs. If you have received a pair where the tweeters are both on the same side, contact your dealer immediately.

M1 Active Mk2 Reference Manual

About the M1 Active Mk2

INSIDE YOUR NEW SPEAKERS

If you’re in a hurry to get started, skip ahead to Chapter 2,

“Speaker Installation”, for connection and placement tips.

ABOUT POWERED MONITORS

The M1 Active Mk2s combine a speaker and amplifiers in the same compact cabinet. Powered monitors are growing in popularity over the traditional separate amplifier and speakers for a number of reasons, convenience and ease of hookup being only one of them. You can connect a powered speaker directly to any line-level source (normally, the control room output of a mixer) simply by connecting a patch cord.

Another benefit is improved sound quality. With careful design, the speaker, amplifier and electronic crossover can be optimised for each other. The M1 Active Mk2s are biamplified, meaning that low frequencies and high frequencies are handled not only by separate speakers (the tweeter and the woofer), but by separate amplifiers. A pair of M1 Active Mk2s contain a total of four power amplifiers. Because of the increased efficiency of biamplification, these are much louder than a single-channel power amplifier of the same wattage feeding a passive crossover, as in other designs. New technology makes it possible to make these high-wattage amplifiers small enough to fit inside the speaker cabinet, with very little weight or size gain.

Since the M1 Active Mk2s are self-powered, DO NOT connect them to the speaker output of another amplifier (such as a powered mixer or hifi receiver). Connect them only to the line-level outputs of such devices (+4 dBu nominal, +24 dBu maximum).


10	M1 Active Reference Manual

About the M1 Active Mk2

TONE

Tonally, every effort has been made to create a powered monitor that is as linear as possible, representing a flat frequency response from 50Hz to 20KHz ±2dB. (see p. 21) Additionally, the use of electronic crossovers within the critical upper midrange frequencies has reduced phase and time delay anomalies often associated with passive crossovers. By including discrete woofer and tweeter amplifiers and application-specific electronic high and low pass crossover filters in the same enclosure the tonal accuracy of the M1 Active Mk2 will always remain constant.

ABOUT THE DRIVERS

The M1 Active Mk2’s 6.5” woofer cone is made of proprietary non-woven carbon fiber. This material is 25% lighter than polypropylene with twice the stiffness for quicker transient response in the low-to-midbass region and vastly improved midrange intelligibility (over polypropylene at 2000 Hz). The non-woven carbon fiber cone, along with the closed cell synthetic rubber surround, are both nearly impervious to ozone, direct sunlight, heat and humidity. Therefore, after an initial break-in period, the sound should remain virtually unchanged for the life of the product.

Alesis’ proprietary-design tweeter features a special wave guide baffle to improve polar response, a silk dome, and low viscosity ferrofluid formulated specifically to retain the best balance of transient response to power handling. The shielded tweeter utilizes a vented pole piece with a separate rear chamber to lower the free air resonance. The low 2000Hz crossover point of this tweeter produces a very widely dispersed, low-distortion signal within the critical midrange frequencies. It is these frequencies which are often the most problematic to get “right” during a mix. The tweeter is designed for an optimal response for non-fatiguing, long term, high level, nearfield mixdowns. This design results in a flat, linear mix when played back on home or car systems from appropriate distances.

MAGNETIC SHIELDING

Your M1 Active Mk2s are at home in recording environments wherein video is a major component. They are magnetically shielded for use in fairly close proximity (3” minimum) to a computer monitor or video screen. (Nonshielded components can make the colors of a screen “smear” or appear out of focus if the speaker is too close.) Magnetic shielding was designed into both the woofer and the tweeter from the beginning so that the system exhibits about low magnetic leakage. Shielding of both the woofer and the tweeter is accomplished by the use of a second opposing-field-oriented “bucking” magnet.

M1 Active Mk2 Reference Manual

About the M1 Active Mk2

THE M1 ACTIVE MK2 BI-AMPLIFIERS & ELECTRONIC

CROSSOVERS

The M1 Active Mk2 uses a 75W woofer amp and a 25W tweeter amp along with 4th order high and low pass electronic crossover filters centered at 2000Hz. Electronic crossovers, which separate the frequencies before being sent to the amplifiers, have fewer phase problems and less power loss than the traditional passive crossover used after the amplifier. Fourth-order filters are steep (24 dB per octave), which minimizes the interaction between woofer and tweeter near the crossover point. Additionally, the high pass (tweeter) section of this system employs an electronic time alignment circuit. Thus the “launch” of frequencies from both the woofer and the tweeter will originate at exactly the same time.

There are several advantages to using built-in amplifiers and active (electronic) crossovers versus a passive network system, most of which have been previously enumerated in Vance Dickason’s “Loudspeaker Design Cookbook”:

•Lower intermodulation distortion due to amplifier operation over a more narrow bandwidth. Also, clipping caused by low frequency overload is reduced, being limited to only one driver within a two driver system.

•Increased dynamic range. The M1 Active Mk2’s 75W and 25W amplifiers in their bi-amp setup will clip at about the same levels as one 200W amplifier operating into a passive crossover.

•Improved transient response.

•Better amplifier/speaker coupling for woofers.

•Better crossover performance working into a constant impedance load.

•Better subjective sound quality than high level (passive) networks.

•Easier control over driver sensitivity differences.

•Easier manipulation of phase, time delay, resonance, and various kinds of shaping, contouring and equalization.

•Specifically in the case of the M1 Active Mk2, the wide, mid-frequency polar response of the tweeter can be utilized down to a low 2000 Hz thereby mating more cohesively with the 6.5" non-woven carbon fiber (NWCF) woofer. This low crossover point is only possible through the use of a steep, electronic fourth-order (24 dB per octave rolloff) high pass filter.

12	M1 Active Reference Manual

About the M1 Active Mk2

THE M1 ACTIVE MK2 POWER SUPPLY

The M1 Active Mk2 employs a regulated switching power supply. This type of supply has previously only been available in amplifiers sold at the very high end of the Pro Audio market.

Most power amp customers are familiar with the large transformer and output capacitors in high quality amplifiers. These large components are used to keep the amplifier’s supply rails as close to DC as possible. For traditional supplies, bigger is better.

But by using Pulse Width Modulation (PWM) and output voltage feedback in the M1 Active Mk2, we have the equivalent of near-infinite transformer and output capacitors, but at a fraction of the cost. PWM provides protection from line voltage surges that would otherwise destroy the amplifier. No user-replaceable fuse is required because nuisance tripping is eliminated. And finally, PWM practically eliminates hum because the line frequency (60 Hz) transformer is replaced with a very high frequency (130,000 Hz) transformer.

The regulated supply rails increase the amplifier dynamic range and reduce clipping distortion under heavy loading. The compact size of the supply does not significantly reduce the internal air volume of the speaker cabinet. And lastly, full power can be maintained even with low or “flat-topped” line voltages.

Note, however, that this switching supply is NOT a universal voltage type that may be used with any input voltage in any country simply by changing the cord. If you wish to use the M1 Active Mk2s in a country whose line voltage is other than 120 volts AC, they must be internally modified or used with a step-down transformer.

THE CABINET AND PORT DESIGN

The M1 Active Mk2 cabinet construction employs vinyl composite material laminated to a .625” MDF (medium density fiberboard) core for the four sides and the rear. The front panel is 1” thick MDF, to withstand the greater demands of the drivers mounted on it. The entire cabinet is braced extensively in random fashion to dissipate intramodal vibration.

M1 Active Mk2 Reference Manual

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