Alesis Studio 12R Reference Manual page 34

By having the correct level at every point in the send/return chain,
you avoid distortion by overloading and avoid noise. The most
common mistake with effect units is to have too low a level at the
send or input, then crank up the output of the processor or the Aux
return to get the effects level desired. This amplifies the noise and
wastes headroom. Here is a procedure that will give good results
with most standard equipment:
1. Set your mixer's input levels correctly, following the
instructions earlier in this chapter.
2. Turn up the channels' [AUX 2] sends to the nominal level
(marked by a heavy dot at the "2:00" position).
3. Play the source.
4. Turn up the input level control of the effect device until you see
its meter or signal LED turn red on peaks; then reduce it slightly
until the red doesn't flash. The ideal input level, for optimum
noise performance, is just below clipping. But if other
instruments will be added to the mix later, or levels are
unpredictable (as in a live show), leave yourself additional
headroom by turning the input level down a bit more.
5. The output level of the effect device should be set at or near its
maximum in most cases, unless distortion occurs.
6. Turn up the [STEREO AUX RETURN] level until you get the
desired level of effect in the mix. The one control in the chain
that may need to be set to a low level is the Aux Return (or
channel) on the mixer. Here is where you should increase or
decrease the overall effect level in the mix, for best low-noise
performance. If you want "just a hint" of reverb, don't turn
down the Aux 2 send; turn down the Aux Return. Leave the
input levels of the effect device where they were set in step 4,
unless you see the device's overload indicator flash.
Studio 12R Reference Manual
Operating Instructions
33