MicroDexed is a compatible 6-operator-FM-synth based on the Teensy(-3.6/-4.x) Microcontroller. https://www.parasitstudio.de
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/* Stereo plate reverb for Teensy 4
*
* Author: Piotr Zapart
* www.hexefx.com
*
* Copyright (c) 2020 by Piotr Zapart
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/***
* Algorithm based on plate reverbs developed for SpinSemi FV-1 DSP chip
*
* Allpass + modulated delay line based lush plate reverb
*
* Input parameters are float in range 0.0 to 1.0:
*
* size - reverb time
* hidamp - hi frequency loss in the reverb tail
* lodamp - low frequency loss in the reverb tail
* lowpass - output/master lowpass filter, useful for darkening the reverb sound
* diffusion - lower settings will make the reverb tail more "echoey", optimal value 0.65
*
*/
#ifndef _EFFECT_PLATERVBSTEREO_H
#define _EFFECT_PLATERVBSTEREO_H
#include <Arduino.h>
#include "Audio.h"
#include "AudioStream.h"
#include "arm_math.h"
// if uncommented will place all the buffers in the DMAMEM section ofd the memory
// works with single instance of the reverb only
#define REVERB_USE_DMAMEM
/***
* Loop delay modulation: comment/uncomment to switch sin/cos
* modulation for the 1st or 2nd tap, 3rd tap is always modulated
* more modulation means more chorus type sounding reverb tail
*/
//#define TAP1_MODULATED
#define TAP2_MODULATED
class AudioEffectPlateReverb : public AudioStream
{
public:
AudioEffectPlateReverb();
virtual void update();
void size(float n)
{
n = constrain(n, 0.0f, 1.0f);
n = map (n, 0.0f, 1.0f, 0.2f, rv_time_k_max);
float32_t attn = 0.5f * map(n, 0.0f, rv_time_k_max, 0.5f, 1.0f);
__disable_irq();
rv_time_k = n;
input_attn = attn;
__enable_irq();
}
void hidamp(float n)
{
n = constrain(n, 0.0f, 1.0f);
__disable_irq();
lp_hidamp_k = 1.0f - n;
__enable_irq();
}
void lodamp(float n)
{
n = constrain(n, 0.0f, 1.0f);
__disable_irq();
lp_lodamp_k = -n;
rv_time_scaler = 1.0f - n * 0.12f; // limit the max reverb time, otherwise it will clip
__enable_irq();
}
void lowpass(float n)
{
n = constrain(n, 0.0f, 1.0f);
n = map(n*n*n, 0.0f, 1.0f, 0.05f, 1.0f);
master_lowpass_f = n;
}
void diffusion(float n)
{
n = constrain(n, 0.0f, 1.0f);
n = map(n, 0.0f, 1.0f, 0.005f, 0.65f);
__disable_irq();
in_allp_k = n;
loop_allp_k = n;
__enable_irq();
}
float32_t get_size(void) {return rv_time_k;}
bool get_bypass(void) {return bypass;}
void set_bypass(bool state) {bypass = state;};
void tgl_bypass(void) {bypass ^=1;}
private:
bool bypass = false;
audio_block_t *inputQueueArray[2];
#ifndef REVERB_USE_DMAMEM
float32_t input_blockL[AUDIO_BLOCK_SAMPLES];
float32_t input_blockR[AUDIO_BLOCK_SAMPLES];
#endif
float32_t input_attn;
float32_t in_allp_k; // input allpass coeff (default 0.6)
#ifndef REVERB_USE_DMAMEM
float32_t in_allp1_bufL[224]; // input allpass buffers
float32_t in_allp2_bufL[420];
float32_t in_allp3_bufL[856];
float32_t in_allp4_bufL[1089];
#endif
uint16_t in_allp1_idxL;
uint16_t in_allp2_idxL;
uint16_t in_allp3_idxL;
uint16_t in_allp4_idxL;
float32_t in_allp_out_L; // L allpass chain output
#ifndef REVERB_USE_DMAMEM
float32_t in_allp1_bufR[156]; // input allpass buffers
float32_t in_allp2_bufR[520];
float32_t in_allp3_bufR[956];
float32_t in_allp4_bufR[1289];
#endif
uint16_t in_allp1_idxR;
uint16_t in_allp2_idxR;
uint16_t in_allp3_idxR;
uint16_t in_allp4_idxR;
float32_t in_allp_out_R; // R allpass chain output
#ifndef REVERB_USE_DMAMEM
float32_t lp_allp1_buf[2303]; // loop allpass buffers
float32_t lp_allp2_buf[2905];
float32_t lp_allp3_buf[3175];
float32_t lp_allp4_buf[2398];
#endif
uint16_t lp_allp1_idx;
uint16_t lp_allp2_idx;
uint16_t lp_allp3_idx;
uint16_t lp_allp4_idx;
float32_t loop_allp_k; // loop allpass coeff (default 0.6)
float32_t lp_allp_out;
#ifndef REVERB_USE_DMAMEM
float32_t lp_dly1_buf[3423];
float32_t lp_dly2_buf[4589];
float32_t lp_dly3_buf[4365];
float32_t lp_dly4_buf[3698];
#endif
uint16_t lp_dly1_idx;
uint16_t lp_dly2_idx;
uint16_t lp_dly3_idx;
uint16_t lp_dly4_idx;
const uint16_t lp_dly1_offset_L = 201;
const uint16_t lp_dly2_offset_L = 145;
const uint16_t lp_dly3_offset_L = 1897;
const uint16_t lp_dly4_offset_L = 280;
const uint16_t lp_dly1_offset_R = 1897;
const uint16_t lp_dly2_offset_R = 1245;
const uint16_t lp_dly3_offset_R = 487;
const uint16_t lp_dly4_offset_R = 780;
float32_t lp_hidamp_k; // loop high band damping coeff
float32_t lp_lodamp_k; // loop low baand damping coeff
float32_t lpf1; // lowpass filters
float32_t lpf2;
float32_t lpf3;
float32_t lpf4;
float32_t hpf1; // highpass filters
float32_t hpf2;
float32_t hpf3;
float32_t hpf4;
float32_t lp_lowpass_f; // loop lowpass scaled frequency
float32_t lp_hipass_f; // loop highpass scaled frequency
float32_t master_lowpass_f;
float32_t master_lowpass_l;
float32_t master_lowpass_r;
const float32_t rv_time_k_max = 0.95f;
float32_t rv_time_k; // reverb time coeff
float32_t rv_time_scaler; // with high lodamp settings lower the max reverb time to avoid clipping
uint32_t lfo1_phase_acc; // LFO 1
uint32_t lfo1_adder;
uint32_t lfo2_phase_acc; // LFO 2
uint32_t lfo2_adder;
};
#endif // _EFFECT_PLATEREV_H