Alesis AI1 User Manual

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RCA input for a sample clock reference. If no sample clock is found (because no device is connected, or the connected device is turned off), the AI-1will then use the fiber optic input.

3.0B Selecting Record Tracks

Once the Source has been determined, the next step is to choose which ADAT tracks are to be used to record the information. This is done by pressing one of the four ADAT CHANNEL buttons on the AI-1front panel: 1/2, 3/4, 5/6, or 7/8.

When an ADAT CHANNEL button is pressed, its LED will light to indicate that it has been selected. Pressing the 1/2 button selects tracks 1 and 2 as the destination, pressing the 3/4 button selects tracks 3 and 4, and so on.

Since the AI-1’soutput is always going to the first ADAT in a multiple ADAT system, the digital audio can be recorded onto two of the first eight tracks. In order to route theAI-1’soutput through the first ADAT to another ADAT in the system, a BRC Master Remote Control must be connected.

It is possible, however, to route digital audio information “through” the first ADAT to a second ADAT connected to it. To do this, you must put both ADATs into Digital Input mode (by pressing the DIGITAL IN button) and put all tracks on the first ADAT into record-ready.By doing so, the first ADAT will route any digital audio information it receives back out to the second ADAT, which in turn can record the information coming from theAI-1.The are two drawbacks to this method. First, a delay of 3 samples will be added to the audio on the second ADAT. Second, you will temporarily be unable to monitor what is on tape on the first ADAT (since it is monitoring the digital input, and not the tape). Using a BRC is the only way to route theAI-1’soutput to multiple ADATs without any delay.

Tip: If you are using a multiple ADAT system without a BRC, we recommend always using the first ADAT in the system to record from theAI-1.If you wish to record information coming from theAI-1onto the tape in ADAT #2 or #3, etc., it is not necessary to reroute the cables. Instead, you should swap tapes with that ADAT and the first ADAT. This way, you can monitor the first

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tape on another ADAT, and you avoid having to reconnect your system.

3.0C Destination

To route the AI-1to ADAT, set theAI-1’sDestination to ADAT by pressing the DESTINATION ADAT button. The button’s LED will be lit indicating it has been selected.

3.0D Converting Sample Rate

If the source you are recording from is already using a 48kHz clock, the 48kHz DESTINATION RATE LED will be lit. This is the same clock that ADAT uses, so there is no need to convert the sample rate.

If the source’s clock rate is 44.1kHz, the 44.1kHz DESTINATION RATE LED will be lit indicating that the ADAT(s) will synchronize to the source’s clock. You now have the option of converting the source’s clock rate to 48kHz, or leaving it at 44.1kHz. Either may be done by pressing the 48kHz button (the 48kHz DESTINATION RATE LED will be lit, indicating it has been selected), or simply by leaving it alone (the 44.1kHz LED will remain lit).

If the source’s clock rate is something other than 48kHz or 44.1kHz, neither DESTINATION RATE LEDs will be lit, and no sample rate conversion will be permitted. In this case, the ADAT(s) will still synchronize to the incoming source’s clock rate.

3.1 ADAT TO AI-1

The AI-1can route up to two ADAT tracks at a time to other digital audio recording equipment from other manufacturers, including: multitrack digital recorders, hard disk recorders, digital effects devices, CD recorders and DAT machines. Since the ADAT digital bus is a proprietary multichannel interface, it is necessary to convert the digital audio of the optic bus into a standard that is compatible with other equipment. The two standards supported are AES/EBU and S/PDIF. It might also be necessary to convert the sample rate of the outgoing digital audio. TheAI-1can convert back and forth

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between 48kHz and 44.1kHz.

3.1A Source

To route the ADAT to the AI-1,set theAI-1’sSource to ADAT by pressing the SOURCE ADAT button. The button’s LED will be lit indicating it has been selected.

Note: When theAI-1’sSource is set to ADAT, theAI-1links the ADAT optic input to the ADAT optic output, so that digital audio is routed from one ADAT to another. This means that, in a two ADAT system, it is possible to make a digital backup of all eight tracks of ADAT #2 to ADAT #1, while simultaneously routing two tracks from ADAT #2 to either an AES/EBU or S/PDIF device.

3.1B Selecting Source Tracks

You may select a pair of ADAT tracks by pressing one of the four ADAT CHANNEL buttons (1/2, 3/4, 5/6 or 7/8). If the AI-1’sDestination is set to AES/EBU or S/PDIF, only one of these four buttons can be selected. If the Destination is set to ADAT, all four button’s LEDs will be lit indicating that all eight tracks may be transmitted/received.

3.1C Destination

To select the AI-1’soutput destination, press one of the three DESTINATION buttons (ADAT, AES/EBU or S/PDIF). The button will be lit to indicate it has been selected. Only one of the Destination buttons can be selected at a time.

Note: TheAI-1provides two types of connectors for S/PDIF devices. When the Destination is set to S/PDIF, the digital audio will be sent out both S/PDIF outputs (fiber optic and RCA). Therefore, it is possible to route theAI-1’soutput to two S/PDIF devices simultaneously.

3.1D Converting Sample Rate

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When the Source is set to ADAT, the AI-1’sDestination Rate will automatically be set to 48kHz, since this is the sample rate of ADAT. If you wish to output the digital audio from theAI-1at 44.1kHz, press the 44.1kHz DESTINATION RATE button (its LED will be lit). This can be used to route digital audio from ADAT to a DAT recorder or CD recorder which uses the lower sampling rate.

3.2 USING THE BRC

The Alesis BRC Master Remote Control can be used to control all of the AI-1’sfunctions. The BRC’s DIGITAL I/O button is used to activate and deactivate theAI-1functions. When the DIGITAL I/O button is enabled, its LED will be lit and the current digital inputs can be recorded to ADAT (the analog inputs will be ignored). The type of digital input that is enabled by this button depends upon the type of digital input that is selected when this function is edited.

If you access the BRC’s Edit mode (by pressing the EDIT button) and select DIGITAL I/O, you can control the AI-1’sparameters (Source, Destination, Destination Rate, and ADAT tracks to be sent out of theAI-1).However, the DIGITAL I/O button must be enabled for any changes you make to affect theAI-1.If you make changes to theAI-1’ssettings from the BRC while the DIGITAL I/O button is off, theAI-1will automatically be updated the next time the DIGITAL I/O button is turned on, so that its setup concurs with the BRC.

3.2A Digital Input

To select the type of digital input on the BRC:

1.Press the DIGITAL I/O button to enable the digital bus (the DIGITAL I/O button LED will go on to indicate it is enabled);

2.Press the EDIT button (the EDIT button LED will go on to indicate you are in Edit mode);

3.Press the DIGITAL I/O button;

The display will read:

Digital input: ADAT

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… or …

Digital input: AES/EBU

… or …

Digital input: S/PDIF

4.Use the UP/DOWN buttons to select the digital input that is to be the source for recording: “ADAT”, “AES/EBU” or “S/PDIF” (the corresponding Source LED on the AI-1will be lit to indicate the current selection);

5.To exit Edit mode, press the EDIT button (the EDIT LED will turn off).

Note: If you change the Digital Input setting while the DIGITAL I/O button is off, theAI-1will not reflect the newly selected digital input. However, the change will automatically be sent to the AI- 1 the next time the DIGITAL I/O button is turned on.

3.2B Bouncing Tracks Between ADATs

The BRC makes it possible to copy tracks between ADATs without leaving the digital domain. The BRC assumes you have connected the digital bus correctly between all ADATs in the system (see section 2.1C). Digital track bouncing is a feature available regardless of whether an AI-1is connected, or not.

If the DIGITAL I/O button on the BRC is pressed again when its digital input display reads "ADAT", you advance to the next window where you may select which track(s) will be routed to the digital bus, and thereby sent to any ADAT tracks that are in record when the DIGITAL I/O button is enabled on the BRC. This allows for digital track copying and backups.

To digitally bounce tracks from the BRC:

1.Press the EDIT button (the EDIT button LED will go on to indicate you are in Edit mode);

2.Press the DIGITAL I/O button;

The display will read:

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Digital input: ADAT

3.Press the DIGITAL I/O button again while the digital input display reads “ADAT”;

The display will show the following:

Select source with trk buttons

All the record and input track LEDs will turn off, as they no longer reflect the record/monitor status. The TRACK INPUT LEDs are now used to reflect the current source tracks.

4.Use the TRACK SELECT buttons to choose the source tracks (that is, the tracks to be assigned to the ADAT digital bus);

To select a single source track, press the desired TRACK SELECT button. The track will now be enabled and its green Input LED will be lit. Pressing the same button again will disable that track and turn off the LED. You may now select a different track.

If you select a track to be a source that was previously put into record-enable,it will automatically be taken out of recordenable. Once a track has been selected as a source, it cannot be put intorecord-enablewhile the DIGITAL I/O button is turned on.

If multiple track sources are desired, they must come from the same tape machine. This is because when one track is chosen, the entire machine becomes the transmitter, while all other connected ADATs become receivers. Only one ADAT can transmit over the digital bus at any given time. When a track is selected as a source, any tracks from other machines that were previously enabled as sources will be disabled automatically.

If no source tracks are selected, the ADATs’ digital outputs will function as digital through connections. This allows for another digital audio device which uses the ADAT proprietary digital multichannel bus, such as the Alesis QuadraSynth, to be connected to the first ADAT’s digital input and thus recorded

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onto any ADAT connected to the digital bus.

5.Press the EDIT button to exit Edit mode;

6.Press the DIGITAL I/O button to enable the digital bus (the DIGITAL I/O LED will go on to indicate it is enabled);

7.Use the TRACK SELECT buttons on the BRC to record-enablethe destination tracks;

8.Initiate recording on the BRC.

The source tracks will be recorded onto the destination tracks in ascending order.

Example:

If source tracks 1, 2, and 3 are selected and tracks 12, 17, and 24 are record enabled, then track 1 will be copied to track 12, track 2 to track 17, and track 3 to track 24.

If more destination tracks are selected than source tracks, the source tracks will repeat (cycle).

Example:

If tracks 25 and 29 were added to the destination tracks of the previous example, then track 1 would be copied to track 25, as well as to track 12, and track 2 would be copied to track 29, as well as track 17.

This type of scheme also allows for copying a single track to multiple tracks.

A digital source track cannot be selected as a digital destination track (i.e. digital source tracks will not be allowed to be record enabled when DIGITAL I/O is enabled).

When copying digital tracks, any track delays and machine offsets will be in effect.

3.2C Recording from AI-1onto ADAT

If either AES/EBU or S/PDIF is selected as the Digital Input, any ADAT tracks that are record enabled while DIGITAL I/O is turned

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on will record the selected Source input from the AI-1.Since only two inputs are available (left and right), these inputs will alternate assignment between all selected record tracks if more than two are selected.

To record from the AI-1onto ADAT using the BRC:

1.Make sure the DIGITAL I/O button is enabled (its LED will be lit);

2.Press the EDIT button (the EDIT button LED will go on to indicate you are in Edit mode);

3.Press the DIGITAL I/O button;

The display will read:

Digital input: ADAT

4.Use the UP button to set the digital input to either “AES/EBU” or “S/PDIF”, depending on which connection you are using on the AI-1(the corresponding Source LED on theAI-1will either be lit solid or flash to indicate the current selection);

Note: 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 provided by the source is neither 48kHz or 44.1kHz.

The display will read:

Digital input: AES/EBU

… or …

Digital input: S/PDIF

Note: If you change the Digital Input setting while the DIGITAL I/O button is off, theAI-1will not reflect the newly selected digital input. However, the change will automatically be sent to the AI- 1 the next time the DIGITAL I/O button is turned on.

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5. Press the DIGITAL I/O button twice;

The display will show the following:

AI-1Destination

ADAT

6.If the AI-1Destination is set to either “AES/EBU” or “S/PDIF”, use the DOWN button to set theAI-1’sDestination to “ADAT”.

7.Press the DIGITAL I/O button again to access the AI-1’sclock rate;

The display will show the following:

AI-1Dest Rate

48K

This determines the output sample rate of the AI-1.When the Digital Input is changed, theAI-1automatically looks for the clock source. When it sees it, the clock rate is determined.

If the source’s clock rate is 44.1kHz, then the 44.1kHz LED on the AI-1will be lit. The Destination Rate can be set to either 44.1kHz or 48kHz.

If the source’s clock rate is 48 kHz, the 48kHz LED on the AI-1will be lit. However, the Destination Rate will have no effect on theAI-1,since you can only record a 48kHz source to ADAT at 48kHz.

If the source’s clock is neither 48kHz nor 44.1kHz, neither LED will light and no conversion will take place. Therefore, the Destination Rate setting on the BRC will have no effect on the AI-1.

8.Use the UP/DOWN buttons to select the AI-1’sDestination Rate (48K or 44.1K).

Important: When recording audio from AES/EBU or S/PDIF, the ADAT(s) derive their clock source from the incoming digital audio via the optic digital bus, and are therefore perfectly in sync

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with the incoming source. However, it is important to note that the BRC also requires a 48kHz clock in order to be synchronized to the incoming digital signal (see section 3.2D). Since the BRC has nothing to do with the ADAT’s optic digital bus, you will need to route clock information from the AI-1to the BRC by connecting theAI-1’s48kHz output to feed the BRC’s 48kHz input (see section 2.1C).

9.Press the EDIT button to exit Edit mode (the EDIT LED will turn off);

10.Use the TRACK SELECT buttons on the BRC to record-enablethe destination tracks;

11. Initiate recording on the BRC.

The source tracks will be recorded onto the destination tracks in ascending order (see previous section 3.2B regarding the guidelines for selecting record tracks).

3.2D BRC Synchronization

It is important that, when recording from AES/EBU or S/PDIF, the BRC is receiving synchronization information from the AI-1’s48kHz clock out. When recording onto ADAT from an AES/EBU or S/PDIF source, the BRC’s 48kHz, SMPTE, and MIDI outputs will not be usable if no timing reference is provided by theAI-1.While the BRC is synchronizing to theAI-1’s48kHz clock, all of the BRC’s sync outputs will be usable. However, it is up to you to insure that the AES/EBU or S/PDIF digital audio signal is synchronous to the clock source that is connected to the BRC by providing it with clock information.

When the DIGITAL I/O button is turned on and the digital input has been set to either AES/EBU or S/PDIF, the EXT SYNC button on the BRC will automatically turn on and disable the pitch controls (the Pitch display will read “ – – – ”). The EXT SYNC’s clock source will be set to 48kHz. It is possible, however, to disable the EXT SYNC button by pressing it without turning off the DIGITAL I/O button. This is not recommended, since the BRC would no longer be in perfect sync with the digital source’s clock rate, which could

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