User Manual

17Quick Start Guide16 500 SERIES COMPRESSOR LIMITER 522
(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.
(8)
Hard Knee switch - Most compression
sounds more natural in soft knee mode
and thus this is the default setting (switch
out). Soft knee compression blurs the
distinction between over threshold and
under threshold signals such that signals
that are a long way below threshold
remain una ected by compression,
and signals that near the threshold get
compressed but at greatly reduced ratios.
When signals are just over threshold the
compressor ratios are still somewhat
reduced and it is only when signals go well
over threshold that full ratio compression
is applied. The soft knee character is
produced after the envelope generation
such that it also modi es the envelope
shapes and typically slows attacks on
programme when it is in the knee area.
This e ect is similar to many vintage
compressors where they exhibit a soft
knee characteristic due to non-linearities
in the gain reduction element. When HARD
Knee is activated, the compressor operates
in a more clinical way with a more de ned
transition between under threshold and
over threshold; this is better suited to
limiting style compression. In this mode a
small amount of soft knee is still retained
to keep the sound reasonably natural. The
switch’s red LED illuminates to show that
that HARD knee is active.
(9)
Side chain high pass  lter switch -
When this is selected, a 200 Hz high pass
 lter is inserted into the compressor side
chain, and this prevents low frequency
signals from dominating compression, and
so it helps to prevent undesirable pumping
e ects on higher frequencies. The switch’s
green LED illuminates to show that the
side chain high pass  lter is active.
(10)
Gain reduction meter (g/r) - The gain
reduction meter indicates the amount
of attenuation being applied by the
compressor. The 10 segment LED meter
reads from 2 dB to 20 dB in 2 dB steps.
(11)
Auto switch - By default the operator can
adjust the compressor manual attack and
release time constants using the attack
and release controls and the compressor
operates in peak mode with linear attack
curves. When the AUTO switch is selected,
the manual attack and release controls are
bypassed and the compressor operates
in RMS mode and automatically sets the
attack and release dependant on the
program material and the threshold/
ratio settings. The switch’s green LED
illuminates to show that theAUTO mode
is active.
(12)
Level meter - This meter indicates the
output signal level. The 6 segment LED
meter reads from -30 dBu to +20 dBu in
10 dB steps.
(13)
Compressor IN switch - This switch
inserts the compressor into the signal
path. The switch’s yellow LED illuminates
to show that the compressor is active.
When the IN switch is deselected, all the
circuitry is completely bypassed (true relay
hardware bypass). True bypass mode also
occurs if the 500 series rack is powered
down, as the signal passes directly from
the rack input XLR to the rack output XLR.
Controls