Qu Mixer Reference Guide
33
AP9372 iss.9
Compressor
The Compressor is a powerful tool for controlling the
dynamics of the sound, for example to smooth out a
bass guitar or to narrow the dynamic range of a vocal
to make it more intelligible in a busy mix. At its extreme
setting the compressor can be used as a limiter to
prevent the signal exceeding a preset maximum level.
A compressor works by dynamically reducing the
amount of gain when the signal increases above a
certain threshold. This pulls back loud moments.
Applying ‘make-up’ gain restores the average volume
and also has the effect of bringing up quiet moments.
The result is a reduced dynamic range.
While listening to the signal adjust Thres (threshold) to
set the point at which compression starts. The GR
indicator and red screen meter will start to show that
compression is active. Set Ratio for how much
compression you want from none (1:1) to full limiting
(Inf). A ratio of 3:1 is a good starting point.
Use the In key or screen button to switch the
compressor in and out and turn up Gain so that the
average volume is similar.
Attack sets how fast the compressor starts to work
when the threshold is reached. Release sets how fast
it stops compressing when the signal drops below the
threshold. For example, adjust these to achieve a
‘punchy’ dynamic sound, or smooth out the response
to reduce an audible ‘pumping’ effect.
Two ‘knee’ settings are available. Hard Knee means
that compression is applied at the set ratio as soon as
the threshold is reached. Soft Knee means that the
compression ratio increases gradually from 1:1 to the
set ratio as it approaches the threshold. The curve
illustrates this.
4 Compressor types are available using the drop-
down menu. Two ‘Manual’ types allow user control of
attack and release. Two ‘Auto’ types provide automatic
control of the compressor dynamics.
Experiment with the effect of the compressor settings
on different sounds. Try to use compression only
where it is needed, and avoid compression in stage
monitor speakers.
Mix processing
The mix masters provide PEQ, GEQ, Compressor, FX
Insert capability and output Delay.
The mixes include Groups, Mono and Stereo Mixes,
and Matrix.
To access the Mix processing press the Qu mixer
master fader strip green
Sel
key or Qu-Pac
Channel
screen select mix button.
Delay up to 170ms can be added to each mix output.
This is typically used to time align the PA to the
acoustic sound from the instruments on stage, or to
align fill loudspeakers to the main PA. Allow 1ms per
foot distance as a starting point.
Mix and Matrix
