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declare description "Nonlinear WaveGuide Acoustic Bass";
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declare author "Romain Michon";
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declare copyright "Romain Michon (rmichon@ccrma.stanford.edu)";
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declare licence "STK-4.3"; // Synthesis Tool Kit 4.3 (MIT style license);
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import("instrument.lib");
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//==================== GUI SPECIFICATION ================
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freq = nentry("h:Basic_Parameters/freq [1][unit:Hz] [tooltip:Tone frequency]",120,20,20000,1);
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gain = nentry("h:Basic_Parameters/gain [1][tooltip:Gain (value between 0 and 1)]",1,0,1,0.01);
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gate = button("h:Basic_Parameters/gate [1][tooltip:noteOn = 1, noteOff = 0]");
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touchLength = hslider("v:Physical_Parameters/Touch_Length
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[2][tooltip:A value between 0 and 1]",0.15,0,1,0.01)*2;
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typeModulation = nentry("v:Nonlinear_Filter_Parameters/Modulation_Type
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[3][tooltip: 0=theta is modulated by the incoming signal; 1=theta is modulated by the averaged incoming signal;
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2=theta is modulated by the squared incoming signal; 3=theta is modulated by a sine wave of frequency freqMod;
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4=theta is modulated by a sine wave of frequency freq;]",0,0,4,1);
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nonLinearity = hslider("v:Nonlinear_Filter_Parameters/Nonlinearity
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[3][tooltip:Nonlinearity factor (value between 0 and 1)]",0,0,1,0.01);
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frequencyMod = hslider("v:Nonlinear_Filter_Parameters/Modulation_Frequency
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[3][unit:Hz][tooltip:Frequency of the sine wave for the modulation of theta (works if Modulation Type=3)]",220,20,1000,0.1);
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//==================== SIGNAL PROCESSING ======================
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//----------------------- Nonlinear filter ----------------------------
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//nonlinearities are created by the nonlinear passive allpass ladder filter declared in filter.lib
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//nonlinear filter order
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//nonLinearModultor is declared in instrument.lib, it adapts allpassnn from filter.lib
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//for using it with waveguide instruments
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NLFM = nonLinearModulator((nonLinearity : smooth(0.999)),1,freq,
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typeModulation,(frequencyMod : smooth(0.999)),nlfOrder);
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//----------------------- Synthesis parameters computing and functions declaration ----------------------------
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//delay length in number of samples
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delayLength = float(SR)/freq;
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//stereoizer is declared in instrument.lib and implement a stereo spacialisation in function of
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//the frequency period in number of samples
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stereo = stereoizer(delayLength);
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excitation = asympT60(-0.5,-0.985,0.02,gate),noise*asympT60(gain,0,touchLength,gate) :
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onePoleSwep : excitationFilter : excitationFilter
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//the exitation filter is a one pole filter (declared in instrument.lib)
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excitationFilter = onePole(0.035,-0.965);
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//the bodyfilter is a bandpass filter (declared in instrument.lib)
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bodyFilter = bandPass(108,0.997);
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//the reflexion filter is pole zero filter (declared in instrument.lib) whose coefficients are
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//modulated in function of the tone being played
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reflexionFilter = poleZero(b0,b1,a1)
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//filter coefficients are stored in a C++ function
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loopFilterb0 = ffunction(float getValueBassLoopFilterb0(float), <bass.h>,"");
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loopFilterb1 = ffunction(float getValueBassLoopFilterb1(float), <bass.h>,"");
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loopFiltera1 = ffunction(float getValueBassLoopFiltera1(float), <bass.h>,"");
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freqToNoteNumber = (log - log(440))/log(2)*12 + 69 + 0.5 : int;
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freqn = freq : freqToNoteNumber;
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b0 = loopFilterb0(freqn);
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b1 = loopFilterb1(freqn);
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a1 = loopFiltera1(freqn);
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delayLine = asympT60(0,delayLength,0.01,gate),_ : fdelay(4096);
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//the resonance duration is different whether a note-on signal is sent or not
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resonanceGain = gate + (gate < 1 <: *(asympT60(1,0.9,0.05)));
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process = excitation :
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(+)~(delayLine : NLFM : reflexionFilter*resonanceGain) <:
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bodyFilter*1.5 + *(0.5) : *(4) : stereo : instrReverb;