+++ /dev/null
-declare name "Faust Oscillator Library";
-declare author "Julius O. Smith (jos at ccrma.stanford.edu)";
-declare copyright "Julius O. Smith III";
-declare version "1.10";
-declare license "STK-4.3"; // Synthesis Tool Kit 4.3 (MIT style license)
-
-import("music.lib"); // SR, ...
-import("filter.lib"); // wgr, nlf2, tf2
-
-//===================== Virtual Analog Oscillators ========================
-
-//------------------------ Impulse Train: imptrain ------------------------
-imptrain(freq) = sawpos(freq)<:-(mem)<0;
-
-//--- Pulse-Train and Square-Wave Oscillators: pulsetrainpos, squarewave[pos]
-// In all cases, the first pulse jumps to 1 at time 0.
-
-// Basic unit-amplitude nonnegative pulse train with duty cycle between 0 and 1:
-pulsetrainpos(freq,duty) = float(sawpos(freq) <= duty);
-
-// Positive square wave = pulse train with 50% duty cycle:
-squarewavepos(freq) = pulsetrainpos(freq,0.5);
-
-// Unit amplitude square wave = zero-mean pulse train with 50% duty cycle:
-squarewave(freq) = 2*squarewavepos(freq) - 1;
-
-//---------- Sawtooth: rawsaw, sawpos, saw1, saw2, sawtooth -------------
-
-// Sawtooth waveform oscillators for virtual analog synthesis et al.
-// The 'simple' versions (rawsaw, sawpos, saw1), are mere samplings of
-// the ideal continuous-time ("analog") waveforms. While simple, the
-// aliasing due to sampling is quite audible. The differentiated
-// polynomial waveform family (saw2,
-
-// --- rawsaw ---
-// simple sawtooth waveform oscillator between 0 and period in samples:
-rawsaw(periodsamps) = (_,periodsamps : fmod) ~ +(1.0);
-
-// --- sawpos ---
-// simple sawtooth waveform oscillator between 0 and 1
-sawpos(freq) = rawsaw(periodsamps) / periodsamps
-with {
- periodsamps = float(SR)/freq; // period in samples (not nec. integer)
-};
-
-// --- saw1 ---
-// simple sawtooth waveform oscillator between -1 and 1
-saw1(freq) = 2.0 * sawpos(freq) - 1.0; // zero-mean in [-1,1)
-
-// --- saw2 ---
-// Differentiated Parabolic Wave sawtooth (less aliasing)
-// Reference: Valimaki, IEEE Signal Processing Letters, March 2005
-saw2(freq) = saw1(freq) <: * <: -(mem) : *(0.25'*SR/freq);
-
-// --- sawtooth ---
-sawtooth = saw2; // default choice
-
-//-------------------------- sawtooth_demo ---------------------------
-// USAGE: sawtooth_demo : _
-
-sawtooth_demo = signal with {
- osc_group(x) = vgroup("[0] SAWTOOTH OSCILLATOR
- [tooltip: See Faust's oscillator.lib for documentation and references]",x);
- knob_group(x) = osc_group(hgroup("[1]", x));
- ampdb = knob_group(vslider("[1] Amplitude [unit:dB] [style:knob]
- [tooltip: Sawtooth waveform amplitude]",
- -20,-120,10,0.1));
- amp = ampdb : smooth(0.999) : db2linear;
- freq = knob_group(
- vslider("[2] Frequency [unit:PK] [style:knob]
- [tooltip: Sawtooth frequency as a Piano Key (PK) number (A440 = key 49)]",
- 49,1,88,0.01) : pianokey2hz);
- pianokey2hz(x) = 440.0*pow(2.0, (x-49.0)/12); // piano key 49 = A440 (also defined in effect.lib)
- detune1 = 1 + 0.01 * knob_group(
- vslider("[3] Detuning 1 [unit:%%] [style:knob]
- [tooltip: Percentange frequency-shift up or down for second oscillator]",
- -0.1,-10,10,0.01));
- detune2 = 1 + 0.01 * knob_group(
- vslider("[4] Detuning 2 [unit:%%] [style:knob]
-[tooltip: Percentange frequency-shift up or down for third detuned oscillator]",
- +0.1,-10,10,0.01));
- portamento = knob_group(
- vslider("[5] Portamento [unit:sec] [style:knob]
- [tooltip: Portamento (frequency-glide) time-constant in seconds]",
- 0.1,0.01,1,0.001));
- sfreq = freq : smooth(tau2pole(portamento));
- tone = (amp/3) *
- (sawtooth(sfreq) + sawtooth(sfreq*detune1) + sawtooth(sfreq*detune2));
- signal = amp * select2(ei, select2(ss, tone, pink_noise), _);
- checkbox_group(x) = knob_group(vgroup("[6] Alternate Signals",x));
- ss = checkbox_group(checkbox("[0]
-[tooltip: Pink Noise (or 1/f noise) is Constant-Q Noise, meaning that it has the same total power in every octave] Pink Noise Instead (uses only Amplitude control on the left)"));
- ei = checkbox_group(checkbox(
- "[1] External Input Instead (overrides Sawtooth/Noise selection above)"));
-};
-
-// --- Correction-filtered versions of saw2: saw2f2, saw2f4 ----
-saw2f2 = saw2 : cf2 with {
- cf2 = tf2(1.155704605878911, 0.745184288225518,0.040305967265900,
- 0.823765146386639, 0.117420665547108);
-};
-
-saw2f4 = saw2 : cf4 with {
- cf4 = iir((1.155727435125014, 2.285861038554662,
- 1.430915027294021, 0.290713280893317, 0.008306401748854),
- (2.156834679164532, 1.559532244409321, 0.423036498118354,
- 0.032080681130972));
-};
-
-// --- sawN, saw3,saw4,saw5,saw6 ---
-// Differentiated Polynomial Wave (DPW) sawtooth (progressively less aliasing)
-// Reference:
-// "Alias-Suppressed Oscillators based on Differentiated Polynomial Waveforms",
-// Vesa Valimaki, Juhan Nam, Julius Smith, and Jonathan Abel,
-// IEEE Tr. Acoustics, Speech, and Language Processing (IEEE-ASLP),
-// Vol. 18, no. 5, May 2010.
-
-sawN(N,freq) = saw1 : poly(N) : D(N-1) : gate(N-1)
-with {
- p0n = SR/freq;
- sawpos = (_,1:fmod) ~ +(1/p0n); // sawtooth waveform in [0,1)
- saw1 = 2*sawpos - 1; // zero average mean, unit max amp
- poly(2,x) = x*x;
- poly(3,x) = x*x*x - x;
- poly(4,x) = poly(2,x)*(poly(2,x) - 2);
- poly(5,x) = pow(x,5) - pow(x,3)*10/3 + x*7/3;
- poly(6,x) = pow(x,6) - 5*pow(x,4) + 7*poly(2,x);
- diff1(x) = (x - x')/(2/p0n);
- diff(N) = seq(n,N,diff1); // N diffs in series
- D(1) = diff1/2;
- D(2) = diff(2)/6;
- D(3) = diff(3)/24;
- D(4) = diff(4)/120;
- D(5) = diff(5)/720;
- gatedelay(n,d,x) = x@(int(d)&(n-1)); // from music.lib
- gate(N) = * (1 : gatedelay(8,N)); // delayed step for blanking startup glitch
-};
-saw3 = sawN(3); saw4 = sawN(4); saw5 = sawN(5); saw6 = sawN(6);
-
-//----------------------- Filter-Based Oscillators ------------------------
-
-// Quick Guide (more complete documentation forthcoming):
-//
-// USAGE: osc[b|r|rs|rc|s|w](f), where f = frequency in Hz.
-//
-// oscb: one-multiply, two-adds, amplitude varies with frequency, avoid dc
-// oscr: four-multipies, two-adds, amplitude unchanging with frequency,
-// dc ok, amp slowly drifts,
-// sine and cosine outputs available (exact phase quadrature)
-// oscrs: sine output of oscr
-// oscrc: cosine output of oscr
-// oscs: two-multiplies, two-adds, amplitude varies slightly with frequency,
-// dc ok, no amp drift, likely optimizable to be the fastest no-drift case
-// oscw: one/two-multiply, three-adds, amplitude steady with frequency, no amp drift,
-// sine and cosine outputs available (exact phase quadrature),
-// numerical difficulty below 10 Hz,
-// likely optimizable to be best (above 10 Hz) for custom silicon
-// (one multiply when frequency is constant, two otherwise).
-
-impulse = 1-1'; // used to start filter-based oscillators
-
-//-------------------------- oscb --------------------------------
-// Sinusoidal oscillator based on the biquad
-//
-oscb(f) = impulse : tf2(1,0,0,a1,1)
-with {
- a1 = -2*cos(2*PI*f/SR);
-};
-
-//-------------------------- oscr --------------------------------
-// Sinusoidal oscillator based on 2D vector rotation,
-// = undamped "coupled-form" resonator
-// = lossless 2nd-order normalized ladder filter
-//
-// Reference:
-// https://ccrma.stanford.edu/~jos/pasp/Normalized_Scattering_Junctions.html
-//
-oscrq(f) = impulse : nlf2(f,1); // sine and cosine outputs
-oscrs(f) = impulse : nlf2(f,1) : _,!; // sine
-oscrc(f) = impulse : nlf2(f,1) : !,_; // cosine
-oscr = oscrs; // default = sine case
-
-//-------------------------- oscs --------------------------------
-// Sinusoidal oscillator based on the state variable filter
-// = undamped "modified-coupled-form" resonator
-//
-oscs(f) = (*(0-1) : sint(wn) : sintp(wn,impulse)) ~ _
-with {
- wn = 2*PI*f/SR; // approximate
- // wn = 2*sin(PI*f/SR); // exact
- sub(x,y) = y-x;
- sint(x) = *(x) : + ~ _ ; // frequency-scaled integrator
- sintp(x,y) = *(x) : +(y): + ~ _ ; // same + state input
-};
-
-//----------------- oscw, oscwq, oscwc, oscws --------------------
-// Sinusoidal oscillator based on the waveguide resonator wgr
-//
-// oscwc - unit-amplitude cosine oscillator
-// oscws - unit-amplitude sine oscillator
-// oscq - unit-amplitude cosine and sine (quadrature) oscillator
-// oscw - default = oscwc for maximum speed
-//
-// Reference:
-// https://ccrma.stanford.edu/~jos/pasp/Digital_Waveguide_Oscillator.html
-//
-oscwc(fr) = impulse : wgr(fr,1) : _,!; // cosine (cheapest at 1 mpy/sample)
-oscws(fr) = impulse : wgr(fr,1) : !,_; // sine (needs a 2nd scaling mpy)
-oscq(fr) = impulse : wgr(fr,1); // phase quadrature outputs
-oscw = oscwc;
-
-//-------------------------- oscrs_demo ---------------------------
-
-oscrs_demo = signal with {
- osc_group(x) = vgroup("[0] SINE WAVE OSCILLATOR oscrs
- [tooltip: Sine oscillator based on 2D vector rotation]",x);
- knob_group(x) = osc_group(hgroup("[1]", x));
-// ampdb = knob_group(vslider("[1] Amplitude [unit:dB] [style:knob]
- ampdb = knob_group(hslider("[1] Amplitude [unit:dB]
- [tooltip: Sawtooth waveform amplitude]",
- -20,-120,10,0.1));
- amp = ampdb : smooth(0.999) : db2linear;
- freq = knob_group(
-// vslider("[2] Frequency [unit:PK] [style:knob]
- hslider("[2] Frequency [unit:PK]
- [tooltip: Sine wave frequency as a Piano Key (PK) number (A440 = 49 PK)]",
- 49,1,88,0.01) : pianokey2hz);
- pianokey2hz(x) = 440.0*pow(2.0, (x-49.0)/12); // (also defined in effect.lib)
- portamento = knob_group(
-// vslider("[3] Portamento [unit:sec] [style:knob]
- hslider("[3] Portamento [unit:sec]
- [tooltip: Portamento (frequency-glide) time-constant in seconds]",
- 0.1,0,1,0.001));
- sfreq = freq : smooth(tau2pole(portamento));
- signal = amp * oscrs(sfreq);
-};
-
-oscr_demo = oscrs_demo; // synonym
-
-//--------------------------- pink_noise --------------------------
-// Pink noise (1/f noise) generator (third-order approximation)
-//
-// USAGE: pink_noise : _;
-//
-// Reference:
-// https://ccrma.stanford.edu/~jos/sasp/Example_Synthesis_1_F_Noise.html
-//
-
-pink_noise = noise :
- iir((0.049922035, -0.095993537, 0.050612699, -0.004408786),
- (-2.494956002, 2.017265875, -0.522189400));
projects / Faustine.git / blobdiff