This version (18 May 2021 09:03) was approved by John Joseph.The Previously approved version (05 Feb 2020 09:25) is available.Diff

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General 2nd Order Filter


The General (2nd-Order) block gives access to a wide variety of 2nd-order (biquad)filter algorithms.

The available filter types are:

  • Unordered List ItemOrdered List ItemParametric
  • Shelving
  • General High-Pass
  • General Low-Pass
  • General Band-Pass
  • General Band-Stop
  • Butterworth Low-Pass / High-Pass
  • Bessel Low-Pass / High-Pass
  • Tone Control
  • IIR Coefficient (direct coefficient entry)
  • 1st-Order Low-Pass / High-Pass
  • All-pass
  • Peaking
  • Notch
  • Chebyshev Low-Pass / High-Pass


To open the filter control window, click on the icon button. Select the desired filter type from the drop-down combo-box list. The filter controls and the icon button image will change to reflect the selected filter type.

Targets Supported

Name ADSP-214xx ADSP-215xx/SC5xx ADAU145x/146x
—————————————————- ——————-- ——————————-- —————————-
General Second Order B/S B/S S
General Eq Slew NA NA S
General Second Order SW Slew Ext NA NA S



——————————————— —————————— ————————————————
Input0AudioInput Channel 0
Lambda0 (For Slew Ext Only)ControlExternal Slew Input for Stage 0


—————————————— —————————— ————————————————
Output0AudioOutput channel 0

Configurable Parameters

GUI Parameter NameDefault ValueRangeFunction Description
StageX_Boost0 dB -10 to +10 dBSet the boost value for a particular filter curve
StageX_Frequency10000 to 96000HzCut-off frequency
StageX_Gain0 dB-15 to +15 dBFilter Gain
StageX_Q1.410.1 to 16Q factor of the filter
StageX_Slope10 to 2Slope controls filter steepness and therefore the transition between the boost/cut and the flat response.
StageX_FilterTypeParametric filterAvailable filter TypesControls the type of the filter
StageX_EnabledOrBypassedTrueTrue/FalseEnabled/Disabled the algorithm
StageX_PhaseFalseTrue/FalseControls the phase of coefficients in 0 degree or 180 degree phase
StageX_LockFrequencyFalseTrue/FalseEnabled/Disabled locks the frequency control
StageX_Slew (For Slew Variant ADAU145x/146x Only)00 to 1SW slew value for individual filter stages applicable only for General EQ Slew Variant
NumStages11 to 20 Number of stages of filter. Change in this value requires re-compilation
NumChannels1 1 to 20Number of input and output channels. Change in this value requires re-compilation
SlewType (For Slew Variant ADAU145x/146x Only)HWSlewHW/SW SlewSlew type for the filter HW/SW
CustomSlew (For Slew Variant ADAU145x/146x Only)0x208A0x0 to 0xFFFFCustom slew value entered by user

Here, * X - Indicates Stage Number

DSP Parameters

Parameter Name Description ADSP-214xx/SC5xx/215xx ADAU145x/146x
———————————— ————————————————————————————— —————————————- —————————-
StageX_B0B0 Filter CoefficientFloatFixPoint8d24
StageX_B1B1 Filter CoefficientFloatFixPoint8d24
StageX_B2B2 Filter CoefficientFloatFixPoint8d24
StageX_A1A1 Filter CoefficientFloatFixPoint8d24
StageX_A2A2 Filter CoefficientFloatFixPoint8d24
slew_mode Slew value for medium size eq slew variant only NA Integer32
StageX_LambdaExponential decay value of filter stage X for SW slew type onlyNAFixPoint8d24


  • X - Stage Number (Changes for each stage coefficients)

resources/tools-software/sigmastudiov2/modules/filters/generalsecondorder.txt · Last modified: 15 May 2021 08:55 by Sreesha Y M