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Dynamics Parameters
241
Appendix
AW2400 Owner’s Manual
An expander is another form of automatic level control.
By attenuating the signal below the threshold, the
expander reduces low-level noise and effectively increases
the dynamic range of the recorded material.
Expander (EXP) parameters:
• Threshold — determines the level of input signal
required to trigger the expander. Signals above the thresh-
old pass through unaffected. Signals at and below the
threshold level are attenuated by the amount specified
using the Ratio parameter. The trigger signal is deter-
mined using the KEYIN SOURCE parameter.
• Ratio — controls the amount of expansion-the change in
output signal level relative to change in input signal level.
With a 1:2 ratio, for example, a 5 dB change in input level
(below the threshold) results in a 10 dB change in output
level. For a 1:5 ratio, a 2 dB change in input level (below
the threshold) results in a 10 dB change in output level.
• Attack — controls how soon the signal is expanded once
the expander has been triggered. With a fast attack time,
the signal is expanded almost immediately. With a slow
attack time, the initial transient of a sound passes through
unaffected.
• Out Gain — sets the expander’s output signal level.
• Knee — sets the transition of the signal at the threshold.
With a hard knee, the transition between unexpanded and
expanded signal is immediate. With the softest knee,
knee5, the transition starts before the signal reaches the
threshold and gradually ends above the threshold.
• Release — determines how soon the expander returns to
its normal gain once the trigger signal level drops below
the threshold.
A compander is a compressor-expander-a combination of
signal compression and expansion. The compander attenu-
ates the input signal above the threshold as well as the
level below the width. For very dynamic material, this
program allows you to retain the dynamic range without
having to be concerned with excessive output signal levels
and clipping.
CompanderH (CPH) and
CompanderS (CPS) parameters:
• Threshold — determines the level of input signal
required to trigger the compander. Signals above the
threshold pass through unaffected. Signals at and below
the threshold level are attenuated by the amount specified
using the Ratio parameter. The trigger signal is deter-
mined using the KEYIN SOURCE parameter.
• Ratio — controls the amount of companding-the change
in output signal level relative to change in input signal
level. With a 2:1 ratio, for example, a 10 dB change in
input level (above the threshold) results in a 5 dB change
in output level. The hard compander (CPH) has a fixed
ratio of 5:1 for expansion and the soft compander (CPS)
has a fixed ratio of 1.5:1 for expansion.
• Attack — controls how soon the signal is companded
once the compander has been triggered. With a fast attack
time, the signal is companded almost immediately. With a
slow attack time, the initial transient of a sound passes
through unaffected.
• Out Gain — sets the compander’s output signal level.
• Width — is used to determine the distance, in decibels,
between the expander and the compressor. With a width of
90 dB, the expander is effectively switched off and the
compander is simply a compressor-limiter. With a smaller
width (30 dB) and a high threshold (0 dB), the compander
is an expander-compressor-limiter.
• Release — determines how soon the compander returns
to its normal gain once the trigger signal level drops below
the threshold.
Parameter Value
Threshold (dB) -54 to 0 (541 points)
Ratio 1.0, 1.1, 1.3, 1.5, 1.7, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0,
6.0, 8.0, 10, 20,
∞ (16 points)
Attack (ms) 0 to 120 (121 points)
Outgain (dB) 0 to +18 (181 points)
Knee hard,1,2,3,4,5 (6 points)
Release (ms) 6 ms to 46.1 sec (160 points)
■ Expander
Threshold = –10dB
Knee = knee5
–70
–60
–50
–40
–30
–20
–10
0
+10
+20
–70 –60 –50 –40 –30 –20 –10 0 +10 +20
dB
dB
Output Level
Input Level
Expansion ratio = 2:1
Parameter Value
Threshold (dB) -54 to 0 (541 points)
Ratio 1.0, 1.1, 1.3, 1.5, 1.7, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0,
6.0, 8.0, 10, 20 (15 points)
Attack (ms) 0 to 120 (121 points)
Outgain (dB) -18 to 0 (181 points)
Width (dB) 1 to 90 (90 points)
Release (ms) 6 ms to 46.1 sec (160 points)
■ Compander
Threshold
Width
–70
–60
–50
–40
–30
–20
–10
0
+10
+20
–70 –60 –50 –40 –30 –20 –10 0 +10 +20
dB
dB
Output Level
Input Level