Dynamics - Yamaha mLAN Mixer Owner's Manual

Dynamics

Dynamics processors are generally used to correct or control signal levels, although they can also be
used creatively to shape a sound's volume envelope. The following sections explain the COMP, GATE,
DUCKING, EXPAND, COMPANDER-(H), and COMPANDER-(S) dynamics processors, their param-
eters, and general applications.
COMP
The COMP processor is a compressor that attenuates signals
above a specified threshold, providing automatic level control.
Vocalists that tend to move toward and away from the micro-
phone while singing produce fluctuating signal levels; some-
times loud, sometimes soft. Likewise, acoustic instruments
with a large dynamic range produce sound levels from pianis-
simo (very soft) through to fortissimo (very loud). In these situ-
ations, it is often difficult to set an average fader level that will
allow a voice or instrument to be heard clearly throughout a
song or piece of music. This is where the compressor comes in
with automatic level control. By automatically reducing high
levels, thus effectively reducing the dynamic range, the com-
pressor makes it much easier to control signals and set appro-
priate fader levels. Reducing the dynamic range also means that
recording levels can be set higher, therefore improving sig-
nal-to-noise performance.
The COMP processor can also be used as a limiter, which is
essentially a compressor with a high ratio setting. Compression
ratios above 10:1 are considered to limit signals rather than
compress them. When an input signal exceeds the specified
threshold level, its level is automatically reduced to the thresh-
old level. This means that the limiter's output level never actu-
ally exceeds the threshold level. Limiters are often used to
prevent signals from overloading amplifiers and tape recorders.
A limiter with a relatively high threshold, for example, could be
used with the stereo outputs to prevent amplifier and speaker
overload.
Parameter
THRESHOLD
–54 dB to 0 dB (55 steps)
OUT GAIN
0.0 dB to +18.0 dB (0.5 dB steps)
KNEE
hard, 1, 2, 3, 4, 5
ATTACK
0–120 ms (1 ms steps)
5 ms–42.3 s (fs = 48 kHz)
RELEASE
6 ms–46 s (fs = 44.1 kHz)
RATIO
1:1, 1.1:1, 1.3:1, 1.5:1, 1.7:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1, 6:1, 8:1, 10:1, 20:1, :1 (16 steps)
THRESHOLD
—This determines the level of input signal required to trigger the compressor. Signals at
a level below the threshold pass through the compressor unaffected. Signals at and above the threshold
level are compressed by the amount specified using the Ratio parameter. The trigger signal is sourced
using the KEY IN parameter.
+20
+10
0
–10
–20
–30
–40
–50
–60
–70
+20
+10
0
–10
–20
–30
–40
–50
–60
–70
Range
29
Compression ratio = 2:1
Threshold = –20dB
Knee = hard
–70 –60 –50 –40 –30 –20 –10 0
Input Level (dB)
Compression ratio = 20:1
Threshold = –20dB
Knee = hard
–70 –60 –50 –40 –30 –20 –10 0
Input Level (dB)
+10 +20
+10 +20