English: A sound created by harmonic additive synthesis. Generated by the following C++ source code (compiled with GNU g++ version 4.5.2 with libsndfile 1.0.23.)

#include <sndfile.h>
#include <cmath>
#include <algorithm>
using namespace std;
const double twopi=8*atan(1);
double Amplitude(int k, double t)
{
double mint=max(4-t,0.0)*max(4-t,0.0);
double sweepamount=0.5*(tanh(t-5)+1);
double amp=0.19*exp(-(mint*0.15+0.1)*(k-1));
amp*=sweepamount*sin(0.25*k-2*t)*sin(0.25*k-2*t)+(1-sweepamount);
if (!(k%2)) amp*=0.5*(tanh(7-t)+1);
return amp;
}
int main()
{
double sr=44100;
int nFrames=int(sr)*10;
double *buf = new double[nFrames];
double t=0, dt=1.0/sr;
double f0=440.0;
int K=44;
for (int n=0; n<nFrames; n++)
{
buf[n]=0;
for (int k=1; k<K; k++) buf[n]+=Amplitude(k,t)*sin(t*twopi*f0*k);
t+=dt;
}
SF_INFO sfinfo;
sfinfo.samplerate=sr;
sfinfo.channels=1;
sfinfo.format=SF_FORMAT_WAV|SF_FORMAT_PCM_16;
SNDFILE *out = sf_open("out.wav", SFM_WRITE, &sfinfo);
sf_writef_double(out, buf, nFrames);
sf_close(out);
delete [] buf;
return 0;
}