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* AudioEffectCompWDR_F32: Wide Dynamic Rnage Compressor
* Created: Chip Audette (OpenAudio) Feb 2017
* Derived From: WDRC_circuit from CHAPRO from BTNRC:
* As of Feb 2017, CHAPRO license is listed as "Creative Commons?"
* MIT License. Use at your own risk.
#ifndef _AudioEffectCompWDRC_F32
#define _AudioEffectCompWDRC_F32
class AudioCalcGainWDRC_F32; //forward declared. Actually defined in later header file, but I need this here to avoid circularity
#include <Arduino.h>
#include <AudioStream_F32.h>
#include <arm_math.h>
#include <AudioCalcEnvelope_F32.h>
#include <AudioCalcGainWDRC_F32.h> //has definition of CHA_WDRC
#include "BTNRH_WDRC_Types.h"
//#include "utility/textAndStringUtils.h"
class AudioEffectCompWDRC_F32 : public AudioStream_F32
//GUI: inputs:1, outputs:1 //this line used for automatic generation of GUI node
//GUI: shortName: CompressWDRC
AudioEffectCompWDRC_F32(void): AudioStream_F32(1,inputQueueArray) { //need to modify this for user to set sample rate
AudioEffectCompWDRC_F32(AudioSettings_F32 settings): AudioStream_F32(1,inputQueueArray) { //need to modify this for user to set sample rate
//here is the method called automatically by the audio library
void update(void) {
//receive the input audio data
audio_block_f32_t *block = AudioStream_F32::receiveReadOnly_f32();
if (!block) return;
//allocate memory for the output of our algorithm
audio_block_f32_t *out_block = AudioStream_F32::allocate_f32();
if (!out_block) return;
Serial.print("data37= "); Serial.print(block->data[37], 6);
//do the algorithm
compress(block->data, out_block->data, block->length);
// transmit the block and release memory
AudioStream_F32::transmit(out_block); // send the FIR output
//here is the function that does all the work
//void cha_agc_channel(float *input, float *output, int cs) {
// //compress(input, output, cs, &prev_env,
// // CHA_DVAR.alfa, CHA_DVAR.beta, CHA_DVAR.tkgain,,, CHA_DVAR.bolt, CHA_DVAR.maxdB);
// compress(input, output, cs);
//void compress(float *x, float *y, int n, float *prev_env,
// float &alfa, float &beta, float &tkgn, float &tk, float &cr, float &bolt, float &mxdB)
void compress(float *x, float *y, int n)
//x, input, audio waveform data
//y, output, audio waveform data after compression
//n, input, number of samples in this audio block
// find smoothed envelope
audio_block_f32_t *envelope_block = AudioStream_F32::allocate_f32();
if (!envelope_block) return;
calcEnvelope.smooth_env(x, envelope_block->data, n);
Serial.print(" Envelope37= "); Serial.print(envelope_block->data[37], 6);
//float *xpk = envelope_block->data; //get pointer to the array of (empty) data values
//calculate gain
audio_block_f32_t *gain_block = AudioStream_F32::allocate_f32();
if (!gain_block) return;
calcGain.calcGainFromEnvelope(envelope_block->data, gain_block->data, n);
Serial.print(" Gain37= "); Serial.println(envelope_block->data[37], 6);
//apply gain
arm_mult_f32(x, gain_block->data, y, n);
// release memory
void setDefaultValues(void) {
//set default values...configure as limitter
5.0f, // attack time (ms)
50.0f, // release time (ms)
24000.0f, // fs, sampling rate (Hz), THIS IS IGNORED!
115.0f, // maxdB, maximum signal (dB SPL)...assumed SPL for full-scale input signal
0.0f, // tkgain, compression-start gain (dB)
55.0f, // tk, compression-start kneepoint (dB SPL)
1.0f, // cr, compression ratio (set to 1.0 to defeat)
100.0f // bolt, broadband output limiting threshold (ie, the limiter. SPL. 10:1 comp ratio)
//set all of the parameters for the compressor using the CHA_WDRC structure
//assumes that the sample rate has already been set!!!
void setParams_from_CHA_WDRC(BTNRH_WDRC::CHA_WDRC *gha) {
//configure the envelope calculator...assumes that the sample rate has already been set!
calcEnvelope.setAttackRelease_msec(gha->attack,gha->release); //these are in milliseconds
//configure the compressor
//set all of the user parameters for the compressor
//assumes that the sample rate has already been set!!!
void setParams(float attack_ms, float release_ms, float maxdB, float tkgain, float comp_ratio, float tk, float bolt) {
//configure the envelope calculator...assumes that the sample rate has already been set!
//configure the WDRC gains
calcGain.setParams(maxdB, tkgain, comp_ratio, tk, bolt);
void setSampleRate_Hz(const float _fs_Hz) {
//pass this data on to its components that care
given_sample_rate_Hz = _fs_Hz;
void setAttackRelease_msec(const float atk_msec, const float rel_msec) {
calcEnvelope.setAttackRelease_msec(atk_msec, rel_msec);
void setKneeLimiter_dBSPL(float _bolt) { calcGain.setKneeLimiter_dBSPL(_bolt); }
void setKneeLimiter_dBFS(float _bolt_dBFS) { calcGain.setKneeLimiter_dBFS(_bolt_dBFS); }
void setGain_dB(float _gain_dB) { calcGain.setGain_dB(_gain_dB); } //gain at start of compression
void setKneeCompressor_dBSPL(float _tk) { calcGain.setKneeCompressor_dBSPL(_tk); }
void setKneeCompressor_dBFS(float _tk_dBFS) { calcGain.setKneeCompressor_dBFS(_tk_dBFS); }
void setCompRatio(float _cr) { calcGain.setCompRatio(_cr); }
void setMaxdB(float _maxdB) { calcGain.setMaxdB(_maxdB); };
float getCurrentLevel_dB(void) { return AudioCalcGainWDRC_F32::db2(calcEnvelope.getCurrentLevel()); } //this is 20*log10(abs(signal)) after the envelope smoothing
float getGain_dB(void) { return calcGain.getGain_dB(); } //returns the linear gain of the system
float getCurrentGain(void) { return calcGain.getCurrentGain(); }
float getCurrentGain_dB(void) { return calcGain.getCurrentGain_dB(); }
AudioCalcEnvelope_F32 calcEnvelope;
AudioCalcGainWDRC_F32 calcGain;
audio_block_f32_t *inputQueueArray[1];
float given_sample_rate_Hz;