/* 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 #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, 0.0, 1.0); n = map (n, 0.0, 1.0, 0.2, rv_time_k_max); float32_t attn = 0.5 * map(n, 0.0, rv_time_k_max, 0.5, 1.0); AudioNoInterrupts(); rv_time_k = n; input_attn = attn; AudioInterrupts(); } void hidamp(float n) { n = constrain(n, 0.0, 1.0); AudioNoInterrupts(); lp_hidamp_k = 1.0 - n; AudioInterrupts(); } void lodamp(float n) { n = constrain(n, 0.0, 1.0); AudioNoInterrupts(); lp_lodamp_k = -n; rv_time_scaler = 1.0 - n * 0.12; // limit the max reverb time, otherwise it will clip AudioInterrupts(); } void lowpass(float n) { n = constrain(n, 0.0, 1.0); n = map(n, 0.0, 1.0, 0.05, 1.0); master_lowpass_f = n; } void diffusion(float n) { n = constrain(n, 0.0, 1.0); n = map(n, 0.0, 1.0, 0.005, 0.65); AudioNoInterrupts(); in_allp_k = n; loop_allp_k = n; AudioInterrupts(); } float32_t get_size(void) {return rv_time_k;} private: 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 = 0.95; 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