This version is outdated by a newer approved version.DiffThis version (18 May 2021 08:58) was approved by John Joseph.The Previously approved version (15 Jan 2021 10:56) is available.Diff

This is an old revision of the document!

Click here to return to the Dynamic Processors page

RMS Compressor


The RMS Compressor block computes the RMS level of the input signal and applies the compressor gain to the input signal based on the RMS value.


  1. RMS Compressor
  2. RMS Compressor with Gain Out

Targets Supported

Name ADSP-214xx ADSP-215xx/SC5xx ADAU145x/146x
——————————————————-- —————————- ——————————-- —————————-
RMS Compressor B/S B/S S
RMS Compressor with Gain Out NA NA S



————————————— —————————— ————————————————
Input1AudioInput channel1


————————————— —————————— ————————————————
Output1AudioOutput channel1

Configurable Parameters

GUI Parameter NameDefault ValueRangeFunction Description
———————————————- —————————- ————————————- ———————————————————————--
TimeConstant121 1 to 8686 dB/sControls the time constant (TC) in dB/second that is used for calculating the RMS input value. The time constant determines how rapidly the compressor will respond to input signal level changes, e.g. the “Attack” time.
Hold0 ms0 to 2000 msControls the time (in ms) the compressor maintains its current output gain setting before it starts decreasing as the input level decrease.
Decay 10 dB/s 0 to 10000 dB/sControls the rate at which the compressor gain decreases in response to decrease in the input signal level, e.g. the “Release” time.
SoftKneeFalseTrue/FalseSoft-knee lets the compressor ease into action, making a less-abrupt change from unprocessed signal to compressed signal. If it is not activated, the default is hard-knee behavior, in which compression rate reduces or increases abruptly with the threshold level
TableAll values are 1-Table values are the gain points used to apply for input signal level
IsDBpsTrueTrue/False Enable /Disable the control's Decay and TimeConstant either in dB or linear
NumChannels11 to 20Number of input and/or output channels. Change in this value requires re-compilation

DSP Parameters

Parameter NameDescriptionADSP-214xx/SC5xx/215xx ADAU145x/146x
—————————— —————————————— ——————————————- ———————————————-
TimeConstantRMS time constant valueFloat 8.24 format
HoldHold valueFloat 8.24 format
DecayDecay valueFloat 8.24 format
TableTable values Float 8.24 format
LogCoeff Constant coefficientsFloat 8.24 format

DSP Parameter Computation

TimeConstant = Abs(1 - 10^(TimeConstant/(10 * (FS + 0.0000001)))), Where TimeConstant is 20000/TimeConstant in dBps Decay = (20000/Decay)/(FS + 0.0000001) (When Decay is in dBps) or Decay/(FS + 0.0000001) (When Decay is in linear) Hold = FS * Hold/1000
Where FS is the sampling rate

resources/tools-software/sigmastudiov2/modules/dynamicsprocessors/rmscompressor.1620804980.txt.gz · Last modified: 12 May 2021 09:36 by John Joseph