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asb2m10
11 years ago
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/*
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============================================================================== |
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PluginFx.cpp |
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Created: 26 Dec 2013 7:13:29pm |
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Author: Pascal Gauthier |
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/**
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* |
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* Copyright (c) 2013-2014 Pascal Gauthier. |
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* Copyright (C) 2013-2014 Filatov Vadim. |
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*
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* Filter taken from the OBXd project : |
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* https://github.com/2DaT/Obxd
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License as |
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* published by the Free Software Foundation; either version 2 of |
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* the License, or (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be |
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* useful, but WITHOUT ANY WARRANTY; without even the implied |
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
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* PURPOSE. See the GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public |
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* License along with this program; if not, write to the Free |
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* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
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* Boston, MA 02110-1301 USA. |
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*/ |
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The LPF is taken from the PD moog~ object. (David Lowenfels)
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Code is based off of Tim Stilson's moog filter code |
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============================================================================== |
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*/ |
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#define _USE_MATH_DEFINES |
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#include <math.h> |
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#include "PluginFx.h" |
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#include "PluginProcessor.h" |
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static float gaintable[199] = { |
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0.999969, 0.990082, 0.980347, 0.970764, 0.961304, 0.951996, 0.94281, 0.933777, 0.924866, 0.916077, 0.90741, 0.898865, 0.890442, |
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0.882141, 0.873962, 0.865906, 0.857941, 0.850067, 0.842346, 0.834686, 0.827148, 0.819733, 0.812378, 0.805145, 0.798004, 0.790955, |
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0.783997, 0.77713, 0.770355, 0.763672, 0.75708 , 0.75058, 0.744141, 0.737793, 0.731537, 0.725342, 0.719238, 0.713196, 0.707245, |
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0.701355, 0.695557, 0.689819, 0.684174, 0.678558, 0.673035, 0.667572, 0.66217, 0.65686, 0.651581, 0.646393, 0.641235, 0.636169, |
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0.631134, 0.62619, 0.621277, 0.616425, 0.611633, 0.606903, 0.602234, 0.597626, 0.593048, 0.588531, 0.584045, 0.579651, 0.575287, |
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0.570953, 0.566681, 0.562469, 0.558289, 0.554169, 0.550079, 0.546051, 0.542053, 0.538116, 0.53421, 0.530334, 0.52652, 0.522736, |
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0.518982, 0.515289, 0.511627, 0.507996 , 0.504425, 0.500885, 0.497375, 0.493896, 0.490448, 0.487061, 0.483704, 0.480377, 0.477081, |
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0.473816, 0.470581, 0.467377, 0.464203, 0.46109, 0.457977, 0.454926, 0.451874, 0.448883, 0.445892, 0.442932, 0.440033, 0.437134, |
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0.434265, 0.431427, 0.428619, 0.425842, 0.423096, 0.42038, 0.417664, 0.415009, 0.412354, 0.409729, 0.407135, 0.404572, 0.402008, |
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0.399506, 0.397003, 0.394501, 0.392059, 0.389618, 0.387207, 0.384827, 0.382477, 0.380127, 0.377808, 0.375488, 0.37323, 0.370972, |
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0.368713, 0.366516, 0.364319, 0.362122, 0.359985, 0.357849, 0.355713, 0.353607, 0.351532, 0.349457, 0.347412, 0.345398, 0.343384, |
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0.34137, 0.339417, 0.337463, 0.33551, 0.333588, 0.331665, 0.329773, 0.327911, 0.32605, 0.324188, 0.322357, 0.320557, 0.318756, |
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0.316986, 0.315216, 0.313446, 0.311707, 0.309998, 0.308289, 0.30658, 0.304901, 0.303223, 0.301575, 0.299927, 0.298309, 0.296692, |
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0.295074, 0.293488, 0.291931, 0.290375, 0.288818, 0.287262, 0.285736, 0.284241, 0.282715, 0.28125, 0.279755, 0.27829, 0.276825, |
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0.275391, 0.273956, 0.272552, 0.271118, 0.269745, 0.268341, 0.266968, 0.265594, 0.264252, 0.262909, 0.261566, 0.260223, 0.258911, |
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0.257599, 0.256317, 0.255035, 0.25375 |
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}; |
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const float dc = 1e-18; |
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inline static float tptpc(float& state,float inp,float cutoff) { |
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double v = (inp - state) * cutoff / (1 + cutoff); |
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double res = v + state; |
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state = res + v; |
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return res; |
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} |
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inline static float tptlpupw(float & state , float inp , float cutoff , float srInv) { |
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cutoff = (cutoff * srInv)*juce::float_Pi; |
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double v = (inp - state) * cutoff / (1 + cutoff); |
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double res = v + state; |
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state = res + v; |
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return res; |
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} |
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static inline float saturate(float input) { //clamp without branching
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#define _limit 0.95 |
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float x1 = fabsf( input + _limit ); |
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float x2 = fabsf( input - _limit ); |
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return 0.5 * (x1 - x2); |
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static float linsc(float param,const float min,const float max) { |
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return (param) * (max - min) + min; |
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} |
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static inline float crossfade(float amount, float a, float b) { |
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return (1-amount) * a + amount * b; |
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static float logsc(float param, const float min,const float max,const float rolloff = 19.0f) { |
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return ((expf(param * logf(rolloff+1)) - 1.0f) / (rolloff)) * (max-min) + min; |
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} |
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void PluginFx::init(int sampleRate) { |
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void PluginFx::init(int sr) { |
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mm=0; |
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s1=s2=s3=s4=c=d=0; |
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R24=0; |
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mmch = (int)(mm * 3); |
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mmt = mm*3-mmch; |
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sampleRate = sr; |
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sampleRateInv = 1/sampleRate; |
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float rcrate =sqrt((44000/sampleRate)); |
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rcor24 = (970.0 / 44000)*rcrate; |
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rcor24Inv = 1 / rcor24; |
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bright = tan((sampleRate*0.5f-10) * juce::float_Pi * sampleRateInv); |
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R = 1; |
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rcor = (480.0 / 44000)*rcrate; |
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rcorInv = 1 / rcor; |
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bandPassSw = false; |
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uiCutoff = 1; |
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uiReso = 0; |
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srate = sampleRate; |
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output = 0; |
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for(int i=0;i<4;i++) |
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state[i] = 0; |
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pCutoff = -1; |
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pReso = -1; |
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} |
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void PluginFx::process(float *work, int sampleSize) { |
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inline float PluginFx::NR24(float sample,float g,float lpc) { |
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float ml = 1 / (1+g); |
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float S = (lpc*(lpc*(lpc*s1 + s2) + s3) +s4)*ml; |
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float G = lpc*lpc*lpc*lpc; |
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float y = (sample - R24 * S) / (1 + R24*G); |
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return y + 1e-8; |
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}; |
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inline float PluginFx::NR(float sample, float g) { |
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float y = ((sample- R * s1*2 - g*s1 - s2)/(1+ g*(2*R + g))) + dc; |
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return y; |
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} |
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void PluginFx::process(float *work, int sampleSize) { |
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// don't apply the LPF if the cutoff is to maximum
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if ( uiCutoff == 1 ) |
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return; |
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// the UI values haved changed
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if ( uiCutoff != pCutoff || uiReso != pReso) { |
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// calc cutoff
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// mel scale freq : http://www.speech.kth.se/~giampi/auditoryscales/
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float freqCutoff = 700 * (pow(M_E,(uiCutoff*4000/1127)-1)) + 20; |
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float fc = 2 * freqCutoff / srate; |
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float x2 = fc*fc; |
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float x3 = fc*x2; |
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p = -0.69346 * x3 - 0.59515 * x2 + 3.2937 * fc - 1.0072; //cubic fit
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// calc reso
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float ix = p * 99; |
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int ixint = floor( ix ); |
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float ixfrac = ix - ixint; |
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Q = uiReso * crossfade( ixfrac, gaintable[ ixint + 99 ], gaintable[ ixint + 100 ] ); |
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if ( uiCutoff != pCutoff || uiReso != pReso ) { |
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rReso = (0.991-logsc(1-uiReso,0,0.991,40)); |
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R24 = 3.5 * rReso; |
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float cutoffNorm = logsc(uiCutoff,60,19000,30); |
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rCutoff = (float)tan(cutoffNorm * sampleRateInv * juce::float_Pi); |
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pCutoff = uiCutoff; |
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pReso = uiReso; |
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R = 1 - rReso; |
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} |
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for (int i=0; i < sampleSize; i++ ) { |
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output = 0.10 * ( work[i] - output ); //negative feedback
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for(int pole=0; pole < 4; pole++) { |
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float temp = state[pole]; |
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output = saturate( output + p * (output - temp)); |
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state[pole] = output; |
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output = saturate( output + temp ); |
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// THIS IS MY FAVORITE 4POLE OBXd filter
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// maybe smooth this value
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float g = rCutoff; |
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for(int i=0; i < sampleSize; i++ ) { |
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float s = work[i]; |
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s = s - 0.45*tptlpupw(c,s,15,sampleRateInv); |
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s = tptpc(d,s,bright); |
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float lpc = g / (1 + g); |
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float y0 = NR24(s,g,lpc); |
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//first low pass in cascade
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double v = (y0 - s1) * lpc; |
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double res = v + s1; |
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s1 = res + v; |
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//damping
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s1 =atan(s1*rcor24)*rcor24Inv; |
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float y1= res; |
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float y2 = tptpc(s2,y1,g); |
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float y3 = tptpc(s3,y2,g); |
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float y4 = tptpc(s4,y3,g); |
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float mc; |
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switch(mmch) { |
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case 0: |
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mc = ((1 - mmt) * y4 + (mmt) * y3); |
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break; |
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case 1: |
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mc = ((1 - mmt) * y3 + (mmt) * y2); |
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break; |
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case 2: |
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mc = ((1 - mmt) * y2 + (mmt) * y1); |
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break; |
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case 3: |
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mc = y1; |
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break; |
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} |
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work[i] = output; |
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output *= Q; //scale the feedback
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//half volume comp
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work[i] = mc * (1 + R24 * 0.45); |
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} |
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} |
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/*
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// THIS IS THE 2POLE FILTER
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for(int i=0; i < sampleSize; i++ ) { |
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float s = work[i]; |
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s = s - 0.45*tptlpupw(c,s,15,sampleRateInv); |
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s = tptpc(d,s,bright); |
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//float v = ((sample- R * s1*2 - g2*s1 - s2)/(1+ R*g1*2 + g1*g2));
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float v = NR(s,g); |
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float y1 = v*g + s1; |
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//damping
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s1 = atan(s1 * rcor) * rcorInv; |
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float y2 = y1*g + s2; |
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s2 = y2 + y1*g; |
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double mc; |
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if(!bandPassSw) |
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mc = (1-mm)*y2 + (mm)*v; |
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else |
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{ |
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mc =2 * ( mm < 0.5 ? |
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((0.5 - mm) * y2 + (mm) * y1): |
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((1-mm) * y1 + (mm-0.5) * v) |
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); |
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} |
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work[i] = mc; |
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} |
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*/ |
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