interpretor/faust-0.9.47mr3/examples/faust-stk/piano.dsp

   1 declare name "Commuted Piano";
   2 declare description "WaveGuide Commuted Piano";
   3 declare author "Romain Michon (rmichon@ccrma.stanford.edu)";
   4 declare copyright "Romain Michon";
   5 declare version "1.0";
   6 declare licence "STK-4.3"; // Synthesis Tool Kit 4.3 (MIT style license);
   7 declare description "A commuted WaveGuide piano.";
   8
   9 import("music.lib");
  10 import("instrument.lib");
  11
  12 //==================== GUI SPECIFICATION ================
  13
  14 freq = nentry("h:Basic_Parameters/freq [1][unit:Hz] [tooltip:Tone frequency]",440,20,20000,1);
  15 gain = nentry("h:Basic_Parameters/gain [1][tooltip:Gain (value between 0 and 1)]",1,0,1,0.01);
  16 gate = button("h:Basic_Parameters/gate [1][tooltip:noteOn = 1, noteOff = 0]");
  17
  18 brightnessFactor = hslider("v:Physical_Parameters/Brightness_Factor
  19 [2][tooltip:A value between 0 and 1]",0,0,1,0.01);
  20 detuningFactor = hslider("v:Physical_Parameters/Detuning_Factor
  21 [2][tooltip:A value between 0 and 1]",0.1,0,1,0.01)*10;
  22 stiffnessFactor = hslider("v:Physical_Parameters/Stiffness_Factor
  23 [2][tooltip:A value between 0 and 1]",0.28,0,1,0.01)*3.7;
  24 hammerHardness = hslider("v:Physical_Parameters/Hammer_Hardness
  25 [2][tooltip:A value between 0 and 1]",0.1,0,1,0.01)*0.1;
  26
  27 //==================== COMMUTED PIANO PARAMETERS ================
  28
  29 //variables to set keybord splitting zone
  30 DCB2_TURNOFF_KEYNUM = 92;
  31 FIRST_HIGH_NOTE = 88;
  32 PEDAL_ENVELOPE_T60 = 7;
  33
  34 //convert an amplitude in db
  35 dbinv(x) = pow(10,0.05*x);
  36
  37 //convert a frequency in a midi note number
  38 freqToNoteNumber = (log-log(440))/log(2)*12+69+0.5 : int;
  39 freqn = freq : freqToNoteNumber;
  40
  41 //a counter that restart a every note-on
  42 cntSample = *(gate)+1~_ : -(1);
  43
  44 //==================== PIANO SOUND BOARD ================
  45
  46 //exponential envelope with 3 phases for the pedal excitation
  47 asympT60pedal(value,T60) = (*(factor) + constant)~_
  48         with{
  49                 attDur = hammerHardness*float(SR);
  50                 target = value*((cntSample < attDur) & (gate > 0));
  51                 factorAtt = exp (-1/(attDur));
  52                 factorG = exp(-1/(2*float(SR)));
  53                 factorT60 = exp(-7/(T60*float(SR)));
  54                 factor = factorAtt*gate*(cntSample < attDur) + (cntSample >= attDur)*gate*factorG + ((gate-1)*-1)*factorT60;
  55                 constant = (1 - factor)*target;
  56         };
  57
  58 //the sound of the piano sound board is generated by noise generator whose output gain is shaped by
  59 //an exponential envelope
  60 soundBoard = dryTapAmp*noise + pedalEnv*noise : *(0.5)
  61         with{
  62                 //the values of the envelope cut-off time are stored in an external C++ function
  63                 dryTapAmpT60 = ffunction(float getValueDryTapAmpT60(float), <piano.h>,"");
  64                 sustainPedalLevel = ffunction(float getValueSustainPedalLevel(float), <piano.h>,"");
  65
  66                 pedalEnvCutOffTime = 1.4;
  67                 noteCutOffTime = freqn : dryTapAmpT60*gain;
  68                 pedalEnvValue = freqn : sustainPedalLevel*0.2;
  69                 noteEnvValue = 0.15;
  70                 dryTapAmp = asympT60(noteEnvValue,0,noteCutOffTime,gate);
  71                 pedalEnv = asympT60pedal(pedalEnvValue,pedalEnvCutOffTime);
  72         };
  73
  74 //==================== HAMMER MODELING ================
  75
  76 //To model the exitation hammer, we filter the sound from the soundboard with a serie of 4 one pole filters
  77 //connected in serie
  78
  79 //onePole is declared in instrument.lib
  80 calcHammer = onePole((1-hammerPole)*hammerGain,-hammerPole)
  81         with{
  82                 //filter gains and coefficients are stored in external C++ files
  83                 loudPole = ffunction(float getValueLoudPole(float), <piano.h>,"");
  84                 softPole = ffunction(float getValuePoleValue(float), <piano.h>,"");
  85                 loudGain = ffunction(float getValueLoudGain(float), <piano.h>,"");
  86                 softGain = ffunction(float getValueSoftGain(float), <piano.h>,"");
  87
  88                 loudPoleValue = loudPole(freqn) + (brightnessFactor*-0.25) + 0.02;
  89                 softPoleValue = softPole(freqn);
  90                 normalizedVelocityValue = 1;
  91                 loudGainValue = loudGain(freqn);
  92                 softGainValue = softGain(freqn);
  93                 overallGain = 1;
  94                 hammerPole = softPoleValue + (loudPoleValue - softPoleValue)*normalizedVelocityValue;
  95                 hammerGain = overallGain*(softGainValue + (loudGainValue - softGainValue)*normalizedVelocityValue);
  96         };
  97
  98 hammer = seq(i,4,calcHammer);
  99
 100 //==================== DC BLOCKERS ================
 101
 102 //the values for the dcblockers a1 are stored in an external C++ file
 103 DCBa1 = ffunction(float getValueDCBa1(float), <piano.h>,"");
 104 dCBa1Value = freqn : DCBa1;
 105 dCBb0Value = 1 - dCBa1Value;
 106
 107 dcBlock1 = poleZero((dCBb0Value*0.5),(dCBb0Value*-0.5),dCBa1Value);
 108
 109 dcBlock2a = oneZero1(0.5,-0.5);
 110
 111 dcBlock2b = onePole(dCBb0Value,dCBa1Value);
 112
 113 //==================== HIGH TUNING CALCULATION ================
 114
 115 //high tones are not generated with the waveguide technique but with a serie of biquad filters
 116
 117 r1_1 = ffunction(float getValuer1_1db(float), <piano.h>,"");
 118 r1_2 = ffunction(float getValuer1_2db(float), <piano.h>,"");
 119 r2 = ffunction(float getValuer2db(float), <piano.h>,"");
 120 r3 = ffunction(float getValuer3db(float), <piano.h>,"");
 121 e = ffunction(float getValueSecondStageAmpRatio(float), <piano.h>,"");
 122 second_partial_factor = ffunction(float getValueSecondPartialFactor(float), <piano.h>,"");
 123 third_partial_factor = ffunction(float getValueThirdPartialFactor(float), <piano.h>,"");
 124 bq4_gEarBalled = ffunction(float getValueBq4_gEarBalled(float), <piano.h>,"");
 125
 126 r1_1Value = r1_1(freqn)/SR : dbinv;
 127 r1_2Value = r1_2(freqn)/SR : dbinv;
 128 r2Value = r2(freqn)/SR : dbinv;
 129 r3Value = r3(freqn)/SR : dbinv;
 130 eValue = e(freqn) : dbinv;
 131 second_partial_factorValue = second_partial_factor(freqn);
 132 third_partial_factorValue = third_partial_factor(freqn);
 133
 134 //set biquad gains and coeffs
 135 gainHighBq(0) = bq4_gEarBalled(freqn)/0.5;
 136 gainHighBq(1) = bq4_gEarBalled(freqn)/0.5;
 137 gainHighBq(2) = 1;
 138 gainHighBq(3) = 1;
 139
 140 b0HighBq(0) = 1;
 141 b0HighBq(1) = 1;
 142 b0HighBq(2) = 1;
 143 b0HighBq(3) = 1;
 144
 145 b1HighBq(0) = 0;
 146 b1HighBq(1) = 0;
 147 b1HighBq(2) = -2*(eValue*r1_1Value+(1-eValue)*r1_2Value)*cos(2*PI*freq/SR);
 148 b1HighBq(3) = 0;
 149
 150 b2HighBq(0) = 0;
 151 b2HighBq(1) = 0;
 152 b2HighBq(2) = eValue*r1_1Value*r1_1Value+(1-eValue)*r1_2Value*r1_2Value;
 153 b2HighBq(3) = 0;
 154
 155 a1HighBq(0) = -2*r3Value*cos(2*PI*freq*third_partial_factorValue/SR);
 156 a1HighBq(1) = -2*r2Value*cos(2*PI*freq*second_partial_factorValue/SR);
 157 a1HighBq(2) = -2*r1_1Value*cos(2*PI*freq/SR);
 158 a1HighBq(3) = -2*r1_2Value*cos(2*PI*freq/SR);
 159
 160 a2HighBq(0) = r3Value*r3Value;
 161 a2HighBq(1) = r2Value*r2Value;
 162 a2HighBq(2) = r1_1Value*r1_1Value;
 163 a2HighBq(3) = r1_2Value*r1_2Value;
 164
 165 highBqs = seq(i,4,*(gainHighBq(i)) : TF2(b0HighBq(i),b1HighBq(i),b2HighBq(i),a1HighBq(i),a2HighBq(i)));
 166
 167 hiPass = oneZero1(b0,b1)
 168         with{
 169                 b0 = -0.5;
 170                 b1 = -0.5;
 171         };
 172
 173 //==================== STRIKE POSITION COMB FILTER EQ ================
 174
 175 eq = _*filterGain : TF2(b0,b1,b2,a1,a2)
 176         with{
 177                 strikePosition = ffunction(float getValueStrikePosition(float), <piano.h>,"");
 178                 bandwidthFactors = ffunction(float getValueEQBandWidthFactor(float), <piano.h>,"");
 179                 eq_gain = ffunction(float getValueEQGain(float), <piano.h>,"");
 180                 eq_tuning = freq/strikePosition(freqn);
 181                 eq_bandwidth = bandwidthFactors(freqn)*freq;
 182                 filterGain = eq_gain(freqn);
 183                 a2 = (eq_bandwidth / SR) * (eq_bandwidth / SR);
 184                 a1 = -2*(eq_bandwidth / SR)*cos(2*PI*eq_tuning/SR);
 185                 b0 = 0.5 - 0.5 * a2;
 186                 b1 = 0;
 187                 b2 = -b0;
 188         };
 189
 190 //==================== PIANO COUPLED STRINGS ================
 191
 192 //values for the couple strings are stored in externals C++ functions
 193 singleStringDecRate = ffunction(float getValueSingleStringDecayRate(float), <piano.h>,"");
 194 singleStringZero = ffunction(float getValueSingleStringZero(float), <piano.h>,"");
 195 singleStringPole = ffunction(float getValueSingleStringPole(float), <piano.h>,"");
 196 stiffnessCoefficient = ffunction(float getValueStiffnessCoefficient(float), <piano.h>,"");
 197
 198 //coupling filter parameters
 199 g = pow(10,((singleStringDecRate(freqn)/freq)/20)); //attenuation per period
 200 b = singleStringZero(freqn);
 201 a = singleStringPole(freqn);
 202 tempd = 3*(1-b)-g*(1-a);
 203 b0Coupling = 2*(g*(1-a)-(1-b))/tempd;
 204 b1Coupling = 2*(a*(1-b)-g*(1-a)*b)/tempd;
 205 a1Coupling = (g*(1-a)*b - 3*a*(1-b))/tempd;
 206
 207 //string stiffness
 208 stiffness = stiffnessFactor*stiffnessCoefficient(freqn);
 209
 210 stiffnessAP = poleZero(b0s,b1s,a1s)
 211         with{
 212                 b0s = stiffness;
 213                 b1s = 1;
 214                 a1s = stiffness;
 215         };
 216
 217 delayG(frequency,stiffnessCoefficient) = fdelay(4096,delayLength)
 218         with{
 219                 allPassPhase(a1,WT) = atan2((a1*a1-1.0)*sin(WT),(2.0*a1+(a1*a1+1.0)*cos(WT)));
 220                 poleZeroPhase(b0,b1,a1,WT) = atan2(-b1*sin(WT)*(1 + a1*cos(WT)) + a1*sin(WT)*(b0 + b1*cos(WT)),
 221                                                    (b0 + b1*cos(WT))*(1 + a1*cos(WT)) + b1*sin(WT)*a1*sin(WT));
 222                 wT = frequency*2*PI/SR;
 223                 delayLength = (2*PI + 3*allPassPhase(stiffnessCoefficient, wT) +
 224                                                 poleZeroPhase((1+2*b0Coupling),
 225                                                 a1Coupling + 2*b1Coupling, a1Coupling, wT)) / wT;
 226         };
 227
 228 coupledStrings = (parallelStrings <: (_,(_+_ <: _,_),_ : _,_,(_ : couplingFilter),_ : adder))~(_,_) : !,!,_
 229         with{
 230                 releaseLoopGain = ffunction(float getValueReleaseLoopGain(float), <piano.h>,"");
 231                 hz = ffunction(float getValueDetuningHz(float), <piano.h>,"");
 232                 coupledStringLoopGain = gate*0.9996 + ((gate-1)*-1)*releaseLoopGain(freqn)*0.9 : smooth(0.999);
 233                 couplingFilter = poleZero(b0Coupling,b1Coupling,a1Coupling);
 234                 hzValue = hz(freqn);
 235                 freq1 = freq + 0.5*hzValue*detuningFactor;
 236                 freq2 = freq - 0.5*hzValue*detuningFactor;
 237                 delay1 = delayG(freq1,stiffness);
 238                 delay2 = delayG(freq2,stiffness);
 239                 parallelStrings(x,y) = _ <: (+(x)*coupledStringLoopGain : seq(i,3,stiffnessAP) : delay1),
 240                                 (_+y*coupledStringLoopGain : seq(i,3,stiffnessAP) : delay2);
 241                 adder(w,x,y,z) = (y <: +(w),+(z)),x ;
 242         };
 243
 244 //stereoizer is declared in instrument.lib and implement a stereo spacialisation in function of
 245 //the frequency period in number of samples
 246 stereo = stereoizer(SR/freq);
 247
 248 //==================== PROCESSING ================
 249
 250 conditionLowNote = freqn < FIRST_HIGH_NOTE;
 251 conditionHighNote = freqn >= FIRST_HIGH_NOTE;
 252
 253 process = soundBoard <: (*(conditionLowNote)*6 : hammer : dcBlock1 : coupledStrings <: +(eq)),
 254 (*(conditionHighNote) : hiPass : dcBlock1 : hammer : dcBlock2a : highBqs : dcBlock2b) :> + : *(12) :
 255 stereo : instrReverb;