Quick Start Guide

14 15Quick Start Guide500 SERIES COMPRESSOR LIMITER 522
(1)
Mounting holes - The 522 module
is mounted to the host 500 series rack
chassis or box such as the Midas Legend
L6 or L10, and secured using two screws
top and bottom.
(2)
Threshold control - This knob
adjusts the operating point for the
compressor. Signals that go over this
point (“over threshold”) will be a ected
by compressor action. Signals that stay
below the threshold will not trigger any
compression. However they may still be
a ected by compression releases from
previous over-threshold signals.
(3)
Ratio control - The compression ratio
knob provides control of the amount of
compression that is applied to signals
that are over threshold. This is expressed
as a ratio of signal level changes from
input to output. For example, when the
compressor is set to 2:1 every 2 dB input
level change will only generate a 1 dB
output level change (assuming the signal
levels are over threshold).
(4)
Attack control - This knob adjusts the
time taken for the compressor to respond
to an over-threshold signal.
(5)
Release control - This knob adjusts the
time the compressor takes to recover after
the program material falls back below
the threshold. Both attack and release
also respond to changes in program level
that remain over threshold. For example,
a signal that reduces in level but remains
above threshold will still trigger a release,
but in this case it will only be a partial
release – because the compressor will still
be required to generate gain reduction,
but now, as appropriate for the new lower
signal level.
(6)
Presence control - When the control
is set to minimum, the compressor
operates with a  at frequency response.
As the control is turned clockwise, the
mid-high frequencies are increasingly
boosted during compression. The presence
function can protect the mid-high
frequencies during compression. It does
this progressively, so that the compressor
appears to operate with two di erent
ratios, one for low frequencies (normal)
and the other for mid-high frequencies
(reduced ratio). The primary e ects of
this are:
• Heavy compression and dynamic
control can be applied without the
programme sounding unnatural.
Reduced compression in the presence
band where the ear is most sensitive
masks the dynamic control that is applied
to the low frequency and very high
frequency signals.
• The compressed material sounds
brighter. However, because no
high frequency gain is added when
compression is not required, noise
during quiet passages is reduced and the
tendency for high frequency howl-round
(which can often be a problem if air
brightness is added by conventional EQ
post compression) is also reduced.
(7)
Gain control - This knob provides
adjustment of up to 18 dB of “make up”
gain, so that the level of the outgoing
compressed signal can be matched to
the incoming uncompressed signal
as required.
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Controls