170 Chapter 13—Dynamics Processors
is reduced to a level set by the Range parameter. The trigger signal is sourced using the KEY IN parameter.
RANGE—This determines the level to which the signal is ducked. For a setting of –80 dB, the signal is virtually cutoff. For a setting of –30 dB, however, the signal is ducked by 30 dB. For a setting of 0 dB, the ducker has no effect.
HOLD— This determines how long ducking remains active once the trigger signal has fallen below the threshold level.
ATTACK—This determines how soon the signal is ducked once the ducker has been triggered. With a fast attack time, the signal is ducked almost immediately. With a slow attack time, however, ducking appears to fade the signal. Too fast an attack time may sound abrupt.
DECAY—This determines how soon the ducker returns to its normal gain once the trigger signal level drops below the threshold.
EXPAND
An expander is similar to a compressor except that it works on signals below the threshold level. By reducing signals below the threshold level, the expander attenuates low-level noise, effectively increasing the dynamic range and improving the signal -to-noise performance. An expander set to an infinite ratio (i.e., ∞:1) is essentially a gate. The following two graphs show typical expander curves. The one on the left shows an expander with an expansion ratio of 2:1 and a hard knee setting. The one on the right shows an expander with an expansion ratio of 2:1 and a soft knee setting of 5.
+20 | | Expansion ratio = 2:1 |
|
+10 | |
|
0 | | Knee = hard |
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| |
+20 | |
+10 | Expansion ratio = 2:1 |
0Knee = 5
–10 | |
–20 | Threshold = –10dB |
|
–30 | |
–40 | |
–50 | |
–60 | |
–70 | |
–70 | –60 | –50 | –40 | –30 | –20 | –10 | 0 | +10 | +20 |
| | | Input Level (dB) | | | |
–70 | –60 | –50 | –40 | –30 | –20 | –10 | 0 | +10 | +20 |
Input Level (dB)
| Parameter | Range |
| | |
| 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) |
| | |
| RELEASE | 5 ms–42.3 s (fs = 48 kHz) |
| 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 expander. Signals above the threshold pass through the expander unaffected. Signals at and below the threshold level are attenuated by the amount specified using the Ratio parameter. The trigger signal is sourced using the KEY IN parameter.