Connections: Chapter 3

DIGITAL AUDIO/OPTICAL HOOKUP

The QSR can output digital audio directly into an Alesis ADAT or ADAT-compatible multitrack digital recorder via fiber optic cable.

The digital connector follows a proprietary Alesis format that carries all four audio outputs of the QSR (Main and Aux, Left and Right) on a single fiber optic cable. Either pair of outputs can be converted into standard AES/EBU or S/PDIF stereo digital audio format by using the Alesis AI-1 interface. Fiber optic cables of various lengths are available from your Alesis dealer. However, the shorter the cable, the better. The model OC cable is 5 meters long and is the maximum length recommended.

To hook up the optical cable between the QSR and an ADAT or AI-1:

Remove the two pieces of clear plastic, tubular sleeving (if present) that protect the tips of the optical cable plug.

Insert one cable end into the QSR [DIGITAL OUT] and the other end into the ADAT or AI-1 DIGITAL IN.

To test the cable and QSR digital output, plug one cable end into the QSR. The other end should emit a soft red light (it is not dangerous to look directly at this light).

RECORDING DIGITAL AUDIO

Once the fiber optic connection is made between the QSR and ADAT or an AI-1, the QSR will output audio on the first four channels of the digital bus (the bus is capable of handling eight channels of digital audio). The MAIN [L] and [R] outputs are routed to channels 1 and 2, while the AUX [L] and [R] outputs are routed to channels 3 and

4.Note that the [VOLUME] knob controls the level of all analog output channels only, and does not control digital output levels. If your digital output is overloading, try reducing the sound level in Program Edit Mode or the Program volume in Mix Edit Mode.

When recording to ADAT (or some other digital audio recorder), it will be slaving to the digital clock accompanying the digital audio emanating from the QSR. This clock can be set to either 48kHz or 44.1kHz, as determined by the Clock function (found in Global Edit Mode). The Clock function has four settings: Int48kHz, Int44.1k, Ext48kHz and Ext44.1k. The default setting is Int48kHz. which is suitable when the digital recorder is using the 48kHz sample rate. However, if the recorder is using the 44.1kHz sample rate, the Clock function should be set to Int44.1k. This ensures that the QSR will be in tune with previously recorded material. See page 118 in Chapter 8 for more information on the Clock parameter.

QSR Reference Manual

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Alesis QSR 64 manual Digital AUDIO/OPTICAL Hookup, Recording Digital Audio