Connections: Chapter 3
QuadraSynth Plus Piano Reference Manual 35
Digital Audio/Optical Hookup
The QuadraSynth Plus 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:
¿Remove the two pieces of clear plastic, tubular sleeving (if present) that
protect the tips of the optical cable plugs.
¡Insert one cable end into the QuadraSynth Plus DIGITAL OUT and the
other end into the ADAT or AI-1 DIGITAL IN.
To test the cable and QuadraSynth Plus digital output, plug one cable end into
the QuadraSynth Plus. 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 Plus
and ADAT or an AI-1, the QuadraSynth Plus 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 QuadraSynth
Plus’s 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 BRC’s 48
kHz CLOCK OUT and the QuadraSynth Plus’s 48 kHz CLOCK IN. For more
information about using the 48 kHz clock, see page 118 in Chapter 8. When using
only one ADAT without the BRC, it is not necessary to connect the 48 kHz Clock.