--- /dev/null
+
+declare name "karplusplus -- Karplus-Strong + Fuzz";
+declare author "Yann Orlarey, Albert Graef";
+declare version "1.0";
+
+import("music.lib");
+
+// control variables
+
+// master volume and pan
+vol = hslider("vol", 0.3, 0, 10, 0.01); // %
+pan = hslider("pan", 0.5, 0, 1, 0.01); // %
+
+// excitator and resonator parameters
+size = hslider("samples", 512, 1, 1024, 1); // #samples
+dtime = hslider("decay time", 4, 0, 10, 0.01);// -60db decay time
+
+// fuzz parameters
+drive = hslider("drive", 0, 0, 50, 0.1); // overdrive factor
+res = hslider("res", 0, 0, 20, 0.1); // filter resonance
+tone = hslider("tone", 20, 1, 20, 0.1); // filter cutoff harmonic
+level = hslider("level", 1, 0, 10, 0.01); // output gain (%)
+
+// voice parameters
+freq = nentry("freq", 440, 20, 20000, 1); // Hz
+gain = nentry("gain", 1, 0, 10, 0.01); // %
+gate = button("gate"); // 0/1
+
+/* The excitator: */
+
+upfront(x) = (x-x') > 0.0;
+decay(n,x) = x - (x>0)/n;
+release(n) = + ~ decay(n);
+trigger(n) = upfront : release(n) : >(0.0) : +(leak);
+leak = 1.0/65536.0; // avoid denormals on Pentium
+excitator = trigger(size);
+
+/* The resonator: */
+
+average(x) = (x+x')/2;
+att(d,t) = 1-1/pow(db2linear(60), d/(SR*t));
+comb(d,a) = (+ : fdelay(4096, d-1.5)) ~ (average : *(1.0-a));
+resonator(d) = comb(d,att(d,dtime));
+
+/* DC blocker (see http://ccrma.stanford.edu/~jos/filters/DC_Blocker.html): */
+
+dcblocker(x) = (x-x') : (+ ~ *(0.995));
+
+// resonant lowpass
+
+// This is a tweaked Butterworth filter by David Werner and Patrice Tarrabia,
+// see http://www.musicdsp.org and http://www.experimentalscene.com for
+// details.
+
+// res = resonance in dB above DC gain
+// freq = cutoff frequency
+
+lowpass(res,freq) = f : (+ ~ g) : *(a)
+with {
+ f(x) = a0*x+a1*x'+a2*x'';
+ g(y) = 0-b1*y-b2*y';
+ a = 1/db2linear(0.5*res);
+
+ c = 1.0/tan(PI*(freq/SR));
+ c2 = c*c;
+ r = 1/db2linear(2.0*res);
+ q = sqrt(2.0)*r;
+ a0 = 1.0/(1.0+(q*c)+(c2));
+ a1 = 2.0*a0;
+ a2 = a0;
+ b1 = 2.0*a0*(1.0-c2);
+ b2 = a0*(1.0-q*c+c2);
+};
+
+/* Fuzz effect. */
+
+clip(x) = f*x+1-f with { f = abs(drive*x)<=1; };
+fuzz(freq) = clip : lowpass(res,tone*freq) : *(level);
+
+/* Karplus-Strong string synthesizer: */
+
+process = vgroup("1-excitator", noise*gain : *(gate : excitator))
+ : vgroup("2-resonator", resonator(SR/freq)) : dcblocker
+ : vgroup("3-fuzz", fuzz(freq))
+ : vgroup("4-master", *(vol) : panner(pan));