Doc Q7.0
57
AUTO
– Turns the Dynamic Attack filter on or off. Turning this switch ON automatically varies the ATTACK
rate according to the program material; the compressor will respond to faster transients with a faster attack.
LOOK AHEAD
– Despite fast attack times, a compressor can fail to “catch” very fast transients.
Look Ahead
introduces a short audio delay so the compressor’s gain control stage has sufficient time to respond to the
detector, which is side-chained with
no
delay. Look ahead can reduce “popping,” especially when heavy
compression is used on very percussive sources.
MIX
– Sets the ratio of wet (compressed) and dry sounds. This should normally be set to “100%.”
THRSH
–
(Threshold) Sets the level at which automatic volume reduction will occur. When input power
exceeds the threshold, the compressor reduces output volume as set by the RATIO. (When the TYPE is set to
“PEDAL”, the
THRESHOLD
is hidden and automatically set to “minus infinity”).
SUSTAIN/RATIO
– In “PEDAL” type compression,
SUSTAIN
increases compression amount as the knob is
turned clockwise. In “STUDIO” type compression,
SUSTAIN
is replaced by
RATIO
, which sets the input-to-output
ratio for signals above the THRESHOLD. A ratio of 2.00 (2:1) means that an input that is 10 dB over the
threshold will increase the output by only 5 dB. A ratio of 10.00 (10:1) means that an input that is 10 dB over
the threshold is reduced to a mere 1 dB above. Setting the
RATIO
to “INFINITY” turns the compressor into a
“limiter,” reducing any level above the threshold
to
the threshold, applying a sort of “ceiling” or “brick-wall
limiting” above which nothing can rise.
ATT
– Attack rate sets how fast the Compressor reduces the volume once the threshold is exceeded. For
guitar, a fast attack rate often works best.
REL
– Release rate determines how quickly the output volume returns to normal once the input level falls
below the compressor’s threshold. Fast release rates can produce a snappy attack, but a setting that is too fast
can cause distortion if used in conjunction with fast attack times and high compression ratios. Slow release
times can keep the entire signal quiet, reducing the gain of passages even though they are below the set
threshold.
In general the release rate should be set slightly faster than the natural release rate of the program material.
An easy way to set the release rate is to strum a chord, watch the gain reduction meter (on PG2 of the EDIT
menu) and set RELEASE rate so the decay observed is slightly faster than the natural decay of the instrument.
EMPH
–
EMPHASIS
creates a cool effect similar to using a filter on the detector. It boosts highs at the
compressor input and then cuts them back to normal levels at the output. Apply this to prevent thumpy lows
from causing your compressor to “pump.”
LEVEL
– Sets the output level of the compressor.
Studio Compressor Parameters
When
TYPE
is set to “STUDIO”, the following additional parameters appear:
KNEE
–
The knee control “softens” the operation of the threshold and the ratio, introducing gain reduction
gradually as signals approach the threshold. With high compression ratios, a hard knee may produce abrupt
gain changes. A soft knee produces a more “transparent” effect since it causes the compressor to engage
gradually.
