Noise Gate (general purpose)

Noise Gate

Samples the audio input and unmutes for audio envelope above a set point. Uses averaging of envelope and hysteresis for noise suppression.


•Audio In | Audio levels
The audio to be sampled.

•Quiet Level | 0.0 to 1 (generally a small fraction of input level)
This sets the average level to use as the trip point. Levels below this are muted at the output.

•Silence Detect Time | seconds (generally fractions of a second)
This tells rolling averager how long to average. The longer the time, the more the noise rejection, but with slower response.

•Hysteresis Fraction | 0 to 1.0 (default 0.25, or 25%)
This sets the fraction of the Quiet Level (above) to use as hysteresis. Hysteresis is a common method to avoid oscillation between on and off states near a system’s trip point, which is most often seen when the measurement is of a slow moving signal in the presence of noise. The hysteresis increases the difference between the value and the trip point once that point has been reached, so as to keep the system well into its new state. The module input lets you set hysteresis as the fraction of the quiet level you’ve previously set.

•Post Capture Hang Time | 0.0 to desired number of seconds.
This keeps the stream open for the set time after it falls below the quiet threshold. Helps with capturing speech into one stream.


Output | audio range
•The gated output, smoothly faded in or out.

Stream on | Logical TRUE (1) or FALSE (0)
When TRUE stream is open.

Avg | Positive number
•This is the output of the rolling averager.


Just quiet level and envelope average

Version History

Revision & File

Noise Gate.audulus (35.4 KB)
Tidied up some looses ends.
Noise Gate.audulus (80.3 KB)


Revision & File
[2020.08.02] Latest looper and gate
Noise Gate and Looper Demo.audulus (332.7 KB)
[2020.07.03.01] in which I hooked up the sound from the noise gate so you’ll hear the immediate as well as the looper output that comes later!
Noise Gate and Looper Demo.audulus (420.3 KB)
Noise Gate and Looper Demo.audulus (420.1 KB)


Just edited it for clarity (especially that really disjointed bit about hysteresis!) and link-fixin’.`


Then I re-edited it to fix the busted demo!


Update gate and demo patch on first post!

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Note, as for the looper, the demo MIDI keyboard patch is set to channel 16. To try on your iPad with screen keyboard pop it open and change it to Omni.