A compressor, expander, limiter, gate and ducking UGen. This dynamic processor uses a hard-knee characteristic. All of the thresholds and ratios are given as direct values, not in decibels!
- Value Params
- attack
The amount of time it takes for the amplitude adjustment to kick in fully. This is usually pretty small, not much more than 10 milliseconds (the default value). I often set it as low as 2 milliseconds (0.002).
- ctrl
The signal whose amplitude controls the processor. Often the same as in, but one may wish to apply equalization or delay to it to change the compressor character (side-chaining), or even feed a completely different signal, for instance in a ducking application.
- in
The signal to be compressed / expanded / gated.
- ratioAbove
Slope of the amplitude curve above the threshold. Values < 1.0 achieve compression (louder signals are attenuated); > 1.0, you get expansion (louder signals are made even louder). For 3:1 compression, you would use a value of 1/3 here.
- ratioBelow
Slope of the amplitude curve below the threshold. If this slope > 1.0, the amplitude will drop off more quickly the softer the control signal gets; when the control signal is close to 0 amplitude, the output should be exactly zero -- hence, noise gating. Values < 1.0 are possible, but it means that a very low-level control signal will cause the input signal to be amplified, which would raise the noise floor.
- release
The amount of time for the amplitude adjustment to be released. Usually a bit longer than attack; if both times are too short, you can get some (possibly unwanted) artifacts.
- thresh
Control signal amplitude threshold, which determines the break point between slopeBelow and slopeAbove. Usually 0..1. The control signal amplitude is calculated using RMS.
- See also
- Companion
- object