Connections
28 QuadraSynth Reference Manual
Digital Audio/Optical Hookup
The QuadraSynth can send digital audio directly into ADAT, which provides better
fidelity than using the analog inputs and outputs.
The digital I/O connector follows a proprietary Alesis format that carries all four
audio outputs 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. 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:
➀Remove the two pieces of clear plastic, tubular sleeving (if present) that protect
the tips of the optical cable plug.
➁Insert one cable end into the QuadraSynth DIGITAL OUT and the other end into
the ADAT or AI-1 DIGITAL IN.
To test the cable and QuadraSynth digital output, plug one cable end into the
QuadraSynth. 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 QuadraSynth and ADAT or an
AI-1, the QuadraSynth 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 Left and
Right outputs are routed to channels 1 and 2, while the Aux Left and Right outputs
are routed to channels 3 and 4. Note that the volume knob controls the level of all
analog and digital output channels simultaneously. Set the volume to maximum for
most applications.
48 kHz Clock In
If your ADAT system has an Alesis BRC Remote Controller, the QuadraSynthÕs
digital clock must be synchronized to the clock coming from the BRC. Connect a
BNC-to-BNC cable (such as the Alesis BN cable) between the BRCÕs 48 kHz CLOCK
OUT and the QuadraSynthÕs 48 kHz CLOCK IN. For more information about using
the 48 kHz clock, see page 110 in Chapter 8. When using only one ADAT without the
BRC, it is not necessary to connect the 48 kHz Clock.
DIGITAL
OUT 48 KHZ
IN
48 KHZ
OUT
DIGITAL
IN SYNC
OUT
SYNC
IN
BRC
ADAT
#3
ADAT
#1
ADAT
#2