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196 lines
6.2 KiB
196 lines
6.2 KiB
/* Stereo plate reverb for Teensy 4
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*
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* Adapted for use in MiniDexed (Holger Wirtz <wirtz@parasitstudio.de>)
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*
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* Author: Piotr Zapart
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* www.hexefx.com
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*
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* Copyright (c) 2020 by Piotr Zapart
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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/***
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* Algorithm based on plate reverbs developed for SpinSemi FV-1 DSP chip
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*
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* Allpass + modulated delay line based lush plate reverb
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*
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* Input parameters are float in range 0.0 to 1.0:
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*
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* size - reverb time
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* hidamp - hi frequency loss in the reverb tail
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* lodamp - low frequency loss in the reverb tail
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* lowpass - output/master lowpass filter, useful for darkening the reverb sound
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* diffusion - lower settings will make the reverb tail more "echoey", optimal value 0.65
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*
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*/
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#ifndef _EFFECT_PLATERVBSTEREO_H
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#define _EFFECT_PLATERVBSTEREO_H
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#include <stdint.h>
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#include <arm_math.h>
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#include "common.h"
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/***
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* Loop delay modulation: comment/uncomment to switch sin/cos
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* modulation for the 1st or 2nd tap, 3rd tap is always modulated
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* more modulation means more chorus type sounding reverb tail
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*/
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//#define TAP1_MODULATED
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#define TAP2_MODULATED
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class AudioEffectPlateReverb
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{
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public:
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AudioEffectPlateReverb(float32_t samplerate);
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void doReverb(const float32_t* inblockL, const float32_t* inblockR, float32_t* rvbblockL, float32_t* rvbblockR,uint16_t len);
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void size(float n)
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{
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n = constrain(n, 0.0f, 1.0f);
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n = mapfloat(n, 0.0f, 1.0f, 0.2f, rv_time_k_max);
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float32_t attn = mapfloat(n, 0.0f, rv_time_k_max, 0.5f, 0.25f);
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rv_time_k = n;
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input_attn = attn;
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}
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void hidamp(float n)
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{
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n = constrain(n, 0.0f, 1.0f);
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lp_hidamp_k = 1.0f - n;
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}
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void lodamp(float n)
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{
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n = constrain(n, 0.0f, 1.0f);
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lp_lodamp_k = -n;
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rv_time_scaler = 1.0f - n * 0.12f; // limit the max reverb time, otherwise it will clip
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}
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void lowpass(float n)
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{
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n = constrain(n, 0.0f, 1.0f);
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n = mapfloat(n*n*n, 0.0f, 1.0f, 0.05f, 1.0f);
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master_lowpass_f = n;
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}
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void diffusion(float n)
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{
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n = constrain(n, 0.0f, 1.0f);
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n = mapfloat(n, 0.0f, 1.0f, 0.005f, 0.65f);
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in_allp_k = n;
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loop_allp_k = n;
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}
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void level(float n)
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{
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reverb_level = constrain(n, 0.0f, 1.0f);
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}
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float32_t get_size(void) {return rv_time_k;}
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bool get_bypass(void) {return bypass;}
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void set_bypass(bool state) {bypass = state;};
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void tgl_bypass(void) {bypass ^=1;}
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float32_t get_level(void) {return reverb_level;}
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private:
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bool bypass = false;
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float32_t reverb_level;
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float32_t input_attn;
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float32_t in_allp_k; // input allpass coeff
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float32_t in_allp1_bufL[224]; // input allpass buffers
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float32_t in_allp2_bufL[420];
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float32_t in_allp3_bufL[856];
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float32_t in_allp4_bufL[1089];
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uint16_t in_allp1_idxL;
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uint16_t in_allp2_idxL;
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uint16_t in_allp3_idxL;
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uint16_t in_allp4_idxL;
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float32_t in_allp_out_L; // L allpass chain output
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float32_t in_allp1_bufR[156]; // input allpass buffers
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float32_t in_allp2_bufR[520];
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float32_t in_allp3_bufR[956];
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float32_t in_allp4_bufR[1289];
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uint16_t in_allp1_idxR;
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uint16_t in_allp2_idxR;
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uint16_t in_allp3_idxR;
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uint16_t in_allp4_idxR;
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float32_t in_allp_out_R; // R allpass chain output
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float32_t lp_allp1_buf[2303]; // loop allpass buffers
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float32_t lp_allp2_buf[2905];
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float32_t lp_allp3_buf[3175];
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float32_t lp_allp4_buf[2398];
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uint16_t lp_allp1_idx;
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uint16_t lp_allp2_idx;
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uint16_t lp_allp3_idx;
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uint16_t lp_allp4_idx;
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float32_t loop_allp_k; // loop allpass coeff
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float32_t lp_allp_out;
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float32_t lp_dly1_buf[3423];
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float32_t lp_dly2_buf[4589];
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float32_t lp_dly3_buf[4365];
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float32_t lp_dly4_buf[3698];
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uint16_t lp_dly1_idx;
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uint16_t lp_dly2_idx;
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uint16_t lp_dly3_idx;
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uint16_t lp_dly4_idx;
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const uint16_t lp_dly1_offset_L = 201; // delay line tap offets
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const uint16_t lp_dly2_offset_L = 145;
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const uint16_t lp_dly3_offset_L = 1897;
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const uint16_t lp_dly4_offset_L = 280;
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const uint16_t lp_dly1_offset_R = 1897;
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const uint16_t lp_dly2_offset_R = 1245;
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const uint16_t lp_dly3_offset_R = 487;
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const uint16_t lp_dly4_offset_R = 780;
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float32_t lp_hidamp_k; // loop high band damping coeff
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float32_t lp_lodamp_k; // loop low baand damping coeff
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float32_t lpf1; // lowpass filters
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float32_t lpf2;
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float32_t lpf3;
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float32_t lpf4;
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float32_t hpf1; // highpass filters
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float32_t hpf2;
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float32_t hpf3;
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float32_t hpf4;
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float32_t lp_lowpass_f; // loop lowpass scaled frequency
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float32_t lp_hipass_f; // loop highpass scaled frequency
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float32_t master_lowpass_f;
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float32_t master_lowpass_l;
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float32_t master_lowpass_r;
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const float32_t rv_time_k_max = 0.95f;
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float32_t rv_time_k; // reverb time coeff
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float32_t rv_time_scaler; // with high lodamp settings lower the max reverb time to avoid clipping
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uint32_t lfo1_phase_acc; // LFO 1
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uint32_t lfo1_adder;
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uint32_t lfo2_phase_acc; // LFO 2
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uint32_t lfo2_adder;
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};
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#endif // _EFFECT_PLATEREV_H
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