Alesis AI1 User Manual

Size:
594.08 Kb
Download

ALESIS

AI-1

Reference Manual

 

TABLE OF CONTENTS

 

CHAPTER 1 : INTRODUCTION

 

1.0

ABOUT THE AI-1 ......................................................................

1

1.1

IMPORTANT NOTES ABOUT THIS MANUAL..................

3

1.2

OVERVIEW OF MAIN FUNCTIONS.....................................

3

 

1.2A Digital Interface ............................................................

3

 

1.2B Digital Audio Synchronization ....................................

4

 

1.2C Sample Rate Conversion ..............................................

4

1.3

BASIC OPERATION .................................................................

5

 

1.3A Source ............................................................................

5

 

1.3B Destination.....................................................................

6

 

1.3C ADAT Channel .............................................................

6

 

1.3D Destination Rate............................................................

7

CHAPTER 2 : HOOKUP

 

2.0

POWER........................................................................................

8

2.1

CONNECTION TO ADAT(S) ..................................................

8

 

2.1A Single ADAT .................................................................

8

 

2.1B Multiple ADATs without the BRC...............................

9

 

2.1C Connecting the BRC.......................................................

11

2.2

AES/EBU AND S/PDIF..............................................................

13

 

2.2A Connecting an AES/EBU Device ................................

13

 

2.2B Connecting an S/PDIF Device .....................................

14

2.3

48 kHz CLOCK OUT .................................................................

15

2.4

POWERING-UP .........................................................................

15

CHAPTER 3 : TRANSFERRING DIGITAL AUDIO

 

3.0

AI-1TO ADAT ...........................................................................

16

 

3.0A Source ............................................................................

16

 

3.0B Selecting Record Tracks ................................................

17

 

3.0C Destination ....................................................................

18

 

3.0D Converting Sample Rate ..............................................

18

3.1

ADAT TO AI-1 ...........................................................................

18

 

3.1A Source ............................................................................

19

 

3.1B Selecting Source Tracks ................................................

19

 

3.1C Destination ....................................................................

19

 

3.1D Converting Sample Rate ..............................................

19

3.2

USING THE BRC .......................................................................

20

 

3.2A Digital Input..................................................................

20

 

3.2B Bouncing Tracks Between ADATs...............................

21

 

3.2C Recording from AI-1onto ADAT................................

23

1

3.2D BRC Synchronization ...................................................

26

3.2E Output ADAT Tracks to AI-1.......................................

26

3.2F Bouncing Tracks While Outputting To AI-1 ...............

28

3.3 CONFIGURATIONS.................................................................

29

3.3A ADAT to AES/EBU (48kHz) .......................................

30

3.3B AES/EBU to ADAT (48kHz)........................................

30

3.3C AES/EBU to ADAT (44.1kHz to 48kHz) ....................

31

3.3D ADAT to AES/EBU (48kHz to 44.1kHz) ....................

31

3.3E AES/EBU to ADAT (44.1kHz) .....................................

32

3.3F ADAT to S/PDIF (48kHz) ............................................

33

3.3G S/PDIF to ADAT (48kHz)............................................

33

3.3H S/PDIF to ADAT (44.1kHz to 48kHz) ........................

34

3.3I ADAT to S/PDIF (48kHz to 44.1kHz) ..........................

34

3.3J S/PDIF to ADAT (44.1kHz) ..........................................

35

3.3K ADAT to ADAT ............................................................

36

3.3L AES/EBU to AES/EBU ................................................

37

3.3M S/PDIF to S/PDIF........................................................

37

CHAPTER 4 : APPENDICES

 

4.0 APPENDIX 1

 

SPECIFICATIONS..................................................................

39

4.1 APPENDIX 2

 

MAINTENANCE/SERVICE INFORMATION ...................

41

4.1A Cleaning ........................................................................

41

4.1B Maintenance...................................................................

41

4.1C Servicing ........................................................................

41

2

CHAPTER 1: INTRODUCTION

1.0 ABOUT THE AI-1

Congratulations! You’ve just purchased a powerful tool that will enhance your ADAT system with incredible digital audio routing flexibility. The AI-1Digital Interface and Sample Rate Converter provides you a way of routing any two ADAT tracks to another digital recording system, or the other way around, and will convert the sampling rate as needed. TheAI-1is essential for either recording digital audio from other sources onto ADAT, or mixing down a 2 track mix from ADAT to a DAT machine or CD recorder, all while remaining in the digital domain. Here are some of the features theAI-1will provide you:

High quality, dual-channeldigital interface.The AI-1 provides the connection between AES/EBU, S/PDIF and ADAT digital formats. With it, you can interface your ADAT digital audio with various professional and consumer digital audio products (such as DAT and CD recorders, and digital audio workstations) with the assurance that the audio never leaves the digital domain.

Sample rate conversion. TheAI-1can automatically detect the sampling rate of an incoming digital audio source. When you want to convert that source, it will transform a 44.1kHz clock to 48kHz, orvice-versa.When routing ADAT digital audio to another digital destination, theAI-1can convert the ADAT’s 48kHz sample rate to 44.1kHz (this is especially useful for creating a mix that’s ready for transfer to CD).

Sample accurate syncing capabilities. Using ADAT’s exclusive Proprietary Synchronization Interface, the AI-1 keeps perfect time with the system. Each ADAT tape is “formatted” with a proprietary Alesis time code that is much more accurate than SMPTE or other time code systems. This process time-stamps the tape to an incredible single-sample accuracy; that is, 1/48,000th of a second. The AI-1 uses the ADAT’s timecode to keep perfectly synchronized while transferring digital audio.

Simple to use. TheAI-1’sfront panel is extremely easy to understand and operate. Just select the source, destination,

1

track(s) and the sampling rate…and you’re up and running! With the BRC Master Remote Control, it’s even easier since all AI-1controls are available from the BRC’s Digital I/O edit menu.

Optic digital interface. ADAT’s Proprietary Multichannel Optic Digital Interface carries up to eight tracks simultaneously via optic cable, allowing for perfect,degradation-freedigital dubbing between ADATs. With analog recording, bouncing tracks or backing up from one multitrack to another loses one generation, which adds hiss and distortion. With digital recording, such procedures will produce a “clone” of the original. This makes it easy to create extra copies of tracks or safety copies of entire tapes, or make multiple copies for distribution. TheAI-1lets you choose a pair of tracks from a single ADAT, and output them to the AES/EBU and S/PDIF connections. This allows for direct digital connection to and from other digital audio recorders, DAT recorders, CDs, hard disk recorders, synthesizers, and more.

Fast and easy hookup. Connection of theAI-1is accomplished via fiber optic digital audio cables, which connect theAI-1to and from a single ADAT or multiple ADAT system. Connection to AES/EBU devices is provided via XLR type connectors. Connection to S/PDIF devices is provided by both fiber optic and RCA connectors.

When used with the BRC and multiple ADATs, the Sync Out of the last ADAT in the chain is connected to the Sync In of the AI- 1, using a 9 pin style sync cable. The last ADAT’s digital out is connected to the AI-1’sdigital in, and theAI-1’sdigital out is connected to the digital in of the first ADAT, using fiber optic cables.

When the BRC is turned on, it automatically becomes the system’s master, and assigns each ADAT an identification number, from first to last in the chain. The BRC also automatically checks to see if an AI-1is connected, and provides remote control over all of its functions.

Voltage tolerant power supply. The AI-1 accepts any AC voltage between 90 and 250 volts.

For more information on digital recording, see Appendix 1 in the ADAT manual. Appendix 2 in the ADAT manual is a glossary of

2

digital recording terms that may be helpful as you read this manual.

1.1 IMPORTANT NOTES ABOUT THIS MANUAL

This manual has been designed as a reference to assist the recording professional in learning the basic operation of the AI-1.All functions are explained in a clear manner, usingstep-by-stepinstructions and illustrations for setting up and performing various operations.

However, it is assumed that you already have some understanding of multitrack recording and digital audio in general. It also assumes you have read the ADAT manual (and the BRC manual, if you are using the BRC) and comprehend its/their operation.

If you have little or no previous experience with multitrack recording or working with digital audio, please read the second manual that comes with the BRC Master Remote Control, entitled BRC Concepts and Applications. It will give you an understanding of how anADAT/BRC/AI-1system functions in real world applications, and the types of things you may expect. It explains why certain features are significant, and how to employ them in your recording routine. Most importantly, there are simple tutorials for commonly performed operations, which illustrate exactly how to put it all together.

In this manual, all connectors, buttons and LEDs are spelled with all capital letters (such as S/PDIF LED button or SOURCE ADAT button).

1.2 OVERVIEW OF MAIN FUNCTIONS

Here is a brief rundown of the AI-1’smain functions:

1.2A Digital Interface

The AI-1provides conversion between ADAT, AES/EBU and S/PDIF digital formats. This means you can record from other digital audio devices onto ADAT, orvice-versa,without ever

3

leaving the digital domain. The AI-1can be used to transfer digital audio back and forth between DAT machines, CD player/ recorders and digital audio workstations. Whenever you transfer digital audio through theAI-1,the result is a perfect, exact duplicate of the original with no degradation or change in audio quality.

1.2B Digital Audio Synchronization

All digital audio protocols, whether Alesis’ Proprietary Multichannel Optical Digital Interface or AES/EBU format, transmit data plus a timing clock that dictates the speed at which the data will be recorded or played back. This timing clock is related to the sample rate. The ADAT speed is controlled automatically to conform to this sample rate whenever its DIGITAL IN LED is lit. Therefore, the PITCH controls on the ADAT have no effect when performing digital transfers onto ADAT.

1.2C Sample Rate Conversion

The AI-1also provides conversion between 48kHz and 44.1kHz sampling rates. If you are recording onto ADAT from a source that is running at 44.1kHz, you can either record at the same rate, or convert it to ADAT’s superior 48kHz sampling rate. One of the best ways to use ADAT is not only as a multitrack recorder, but as a mixdown recorder as well, using two tracks to mix to. Using the AI- 1, you can transfer thetwo-trackmix to DAT or a CD recorder and simultaneously convert the audio to the required 44.1kHz sample rate.

Because of its superior sound quality, it is always better to record onto ADAT at the 48kHz rate, even when the original audio was recorded at 44.1kHz. Contrary to what many people think, converting 44.1kHz audio to 48kHz does not change the sound quality in any way. If, however, you choose to not to convert such an audio source and record it onto ADAT at 44.1kHz, don’t be surprised when you play back the ADAT recording and hear the music a little faster and transposed up a bit. This is because 48kHz is literally a faster sampling rate than 44.1kHz. When the AI-1sends 44.1kHz audio to ADAT, the ADAT’s motor slows down to match the rate of the incoming audio. If you are monitoring other prerecorded tracks on the same machine, you’ll notice that they are now slower and transposed down.

4

When you play back the audio once it is on ADAT, it will adjust back to its normal speed and of course sound sharp…roughly 147 cents sharp. If you want to hear the audio on ADAT at the original pitch and speed, bring the ADAT’s pitch setting down to -147.Doing so will temporarily show “44.1” in the ADAT’s LED display, indicating that you are now running at the equivalent to the 44.1kHz rate.

1.3 BASIC OPERATION

When power is first turned on, the AI-1recalls the most recent mode of operation (the last mode before power down). The mode is indicated by the LEDs in the control buttons. These buttons are used to change the operating mode. The ADAT CHANNEL buttons, the DESTINATION RATE buttons, and the SOURCE and DESTINATION buttons define the possible uses of theAI-1.

1.3A Source

The three SOURCE buttons (ADAT, AES/EBU, and S/PDIF) are used to select the digital source. When one of these buttons is pressed, its LED will be lit indicating it has been selected. Only one of the sources can be selected at a time; the corresponding format input will be enabled, while the others will be disabled.

Here are descriptions of the three Source possibilities:

ADAT: This allows two tracks from a connected ADAT to be transmitted to another ADAT, or an AES/EBU or S/PDIF device (depending on the Destination setting).

AES/EBU: This allows two tracks from a connected AES/EBU device to be recorded to an ADAT, or another AES/EBU device, or an S/PDIF device (depending on the Destination setting).

S/PDIF: This allows two tracks from a connected S/PDIF device to be recorded to an ADAT, or another S/PDIF device, or an AES/EBU device (depending on the Destination setting).

If the selected Source button’s LED lights solid, it means that a

5

device is connected, and the AI-1is receiving its clock information. If the selected Source button’s LED flashes, it means that either no device is connected to the selected input, or the clock information is not being provided by the source to theAI-1,or the clock information being provided by the source is neither 48kHz or 44.1kHz (see section 1.3D)

1.3B Destination

The three DESTINATION buttons (ADAT, AES/EBU, and S/PDIF) are used to select the digital destination. When one of these buttons is pressed, its LED will be lit indicating it has been selected. Only one of the destinations can be selected at a time; the corresponding format output will be enabled, while the others will be disabled.

Here are descriptions of the three Destination possibilities:

ADAT: This routes the AI-1output to a connected ADAT for recording from another ADAT, or an AES/EBU or S/PDIF device (depending on the Source setting).

AES/EBU: This routes the AI-1output to a connected AES/EBU device for recording from an ADAT, or another AES/EBU device, or an S/PDIF device (depending on the Source setting).

S/PDIF: This routes the AI-1output to a connected S/PDIF device for recording from an ADAT, or another S/PDIF device, or an AES/EBU device (depending on the Source setting).

1.3C ADAT Channel

The four ADAT CHANNEL buttons (1/2, 3/4, 5/6, and 7/8) are used to select two channels on which an ADAT will transmit or receive digital audio. When one of these buttons is pressed, its LED will be lit indicating it has been selected. Only the four defined channel groupings (1 & 2, 3 & 4, 5 & 6, or 7 & 8) may be selected from the front panel.

In most cases, only one of the four ADAT CHANNEL buttons will be lit, indicating the two channels on which an ADAT will transmit or receive audio. If both the Source and Destination are set to ADAT, all four ADAT CHANNEL buttons will be lit indicating that

6

all eight channels of the ADAT digital bus are transferred.

When using the BRC Master Remote Control, any two channels can be selected, in which case the ADAT CHANNEL button(s) corresponding to each selected channel will be lit. Example: if the BRC is used to select channels 2 and 5 as the ADAT channels, two of the AI-1’sADAT CHANNEL buttons (the 1/2 and 5/6 buttons) will be lit indicating the groupings which contain the selected channels.

1.3D Destination Rate

The DESTINATION RATE buttons (48kHz and 44.1kHz) are used to select the AI-1’ssample clock output. When one of these buttons is pressed, its LED will be lit indicating it has been selected.

Only one of the two DESTINATION RATE buttons will be lit to indicate the output sampling rate. The input rate is automatically set to match that of the digital source (i.e. whatever rate the source uses, the AI-1will automatically detect it and adjust the sampling rate accordingly).

Here are descriptions of the two Destination Rate possibilities:

48kHz: If the source rate is 48kHz, this button’s LED will be lit indicating the AI-1’ssample rate. If the source rate is 44.1kHz, pressing the 48kHz button will convert the source’s sample rate to 48kHz.

44.1kHz: If the source rate is 44.1kHz, this button’s LED will be lit indicating the AI-1’ssample rate. If the source rate is 48kHz, pressing the 44.1kHz button will convert the source’s sample rate to 44.1kHz.

Note: If theAI-1’sDestination is set to ADAT and the source’s sample rate is 48kHz, you will not be able to select the 44.1kHz button nor alter theAI-1’soutput rate. This is because ADAT already uses a 48kHz sample rate, which is of course superior to 44.1kHz.

If the source rate is neither 48kHz or 44.1kHz, the SOURCE button LED corresponding to the source (ADAT, AES/EBU or S/PDIF) will flash, and no sample rate conversion will be allowed. This will be

7