This version (18 May 2021 08:59) was approved by Sreesha Y M.

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RMS Index Selectable


This block uses an rms dynamics processor that lets you control the rms TC (time constant) and Soft Knee behavior, and opens the compression curve graph for your curve drawing.

RMS works on a longer average than peak processors, thus allowing some fast loud transients to pass without compression, but operating more on longer segments that exceed the threshold.

This module has stage growth and each stage can have its own compression ratio set using the compressor plot individually. The index selection pin selects the desired stage to be used on the target.

Targets Supported

Name ADSP-214xx ADSP-215xx/SC5xx ADAU145x/146x
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RMS Index Selectable NA B NA



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IndexInputControlIndex Selection Input
Input0AudioInput channel1
ExtDetectInputControlExt Detector Input


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Output0AudioOutput channel1

Configurable Parameters

GUI Parameter NameDefault ValueRangeFunction Description
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Hold_StageX0 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_StageX 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.
SoftKnee_StageXFalseTrue/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 by default-Table values are the output to input gain level points
IsDBps_StageXTrueTrue/False Enable /Disable the Control Decay to be either in dB or linear scale
NumChannels11 to 20Number of input and/or output channels. Change in this value requires re-compilation
NumStages11 to 10Number of Stages of Compressor. Change in this value requires re-compilation

Note : _StageX - Refers to parameters of each stage. X represents the stage index.

DSP Parameters

Parameter NameDescriptionADSP-214xx/SC5xx/215xx ADAU145x/146x
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Hold_StageXHold valueFloat 8.24 format
Decay_StageXDecay valueFloat 8.24 format
Table_StageXTable values Float 8.24 format
TimeConstant_StageXTime Constant Float 8.24 format

Note : _StageX indicates the dsp parameters associated with a particular stage. X represents the stage index

DSP Parameter Computation

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/rmsindexselectable.txt · Last modified: 12 May 2021 09:36 by John Joseph