User Manual

MIXER EFFECTS
65
be flexible enough to cover a broad range of
applications. By adjusting Gain and Bandwidth
together, you can emulate the smooth and musical
character of classic analog EQ circuits, in which the
Gain/Bandwidth dependency was dictated by the
actual circuit design and electrical components
used.
Low and high shelf filters
The Low and High bands offer a shelf option that is
similar to those found in most conventional
parametric EQs.
COMPRESSOR
All mixer input channel strips provide a
compressor module.
Figure 8-4: The Compressor module.
The Compressor (Figure 8-4) lowers the level of the
input when amplitude of the signal is above the
Threshold. The amount of attenuation is
determined by the Ratio and the input level. For
example, if the input is 6 dB above the Threshold
and the Ratio is 3:1, the compressor will attenuate
the signal to 2 dB above the Threshold. When the
input level goes above the threshold, the
attenuation is added gradually to reduce distortion.
The rate at which the attenuation is added is
determined by the Attack parameter. Likewise,
when the input level falls below the Threshold, the
attenuation is removed gradually. The rate at which
the attenuation is removed is determined by the
Release parameter. Long Release times may cause
the audio to drop out briefly when a soft passage
follows a loud passage. Short Release times may
cause the attenuation to “pump”, a term used to
describe the sound of the compressor when the
average input level quickly fluctuates above and
below the Threshold. These types of issues can be
addressed by adjusting the compressor’s
parameters, or applying the Leveler instead. Gain
adjusts the overall output level of the compressor,
post processing. The Level meter (Figure 8-4)
shows the level of the input signal entering the
compressor. It shows either the Peak envelope or
the RMS level, if enabled.
Gain reduction meter
The Gain reduction meter (Figure 8-4) displays the
current amount of attenuation applied by the
compressor, before the makeup gain stage.
RMS mode
By default, the compressor operates in Peak mode,
which uses signal peaks to determine the input
level. In RMS mode, the compressor measures the
input signal’s loudness, using the root-mean-
square computational method. When RMS is
disabled, RMS mode will let brief peaks through
because the detector sidechain is only looking at
the average signal level. By contrast, peak mode
will catch those brief peaks. Peak mode is generally
used for drums, percussion and other source
material with strong transients, while RMS mode is
mostly used for everything else.
The level meter shows either the peak level or the
RMS level, depending on the mode.