Overview

Single band of a cascade graphic equalizer

Discussion

This module implements a single stage of a graphic equalizer. The stage provides boost or cut over a specified frequency range. A multistage graphic EQ subsystem is constructed as a series cascade of these modules. The multistage graphic EQ is contained within graphic_eq_subsystem.m. This module is typically not used directly. Instead, use the graphic_eq_subsystem.m

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Internally, the filter is implemented as a cascade of second order biquad sections. These filters are smoothly updating based upon the variable .smoothingTime. Note, some low frequency filters may go unstable if the smoothingTime is too large.

Type Definition

typedef struct _ModuleGraphicEQBandFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    FLOAT32 gain;                                 // Gain in the center of the band, in dB
    FLOAT32 lowerEdge;                            // Lower frequency edge of the band, in Hz
    FLOAT32 upperEdge;                            // Upper frequency edge of the band, in Hz
    INT32 numStages;                              // Number of 2nd order stages in the filter
    awe_modBiquadCascadeFract32Instance *filt; // Cascade of second order Biquad filters
} ModuleGraphicEQBandFract32Class;

Variables

Properties

Pins

Input Pins

Name: in

Description: audio input

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Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: audio output

Data type: fract32

MATLAB Usage

File Name: graphic_eq_band_fract32_module.m

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