How to play:

1. Left click and drag the [ball, green] circles to change the magnitude of each Fourier functions [Sin nf, Cos nf].
2. Right click the mouse button to change the magnitude between 0 and 1.0
3. Click Play to turn on the sound effect, Stop to turn it off.
4. The coefficient of sin(0f) is used as amplification factor for all modes.
(Use it to change the sound level)，the coefficient of cos(0f) is the DC component.
5. Click the checkbox at the top(after stop) will show square the the amplitude of the signal.

The default value for base frequency is f=2200Hz, you can change it from the TextField. (20 < f < 2000). The ear is 1000 times more sensitive at 1kHz than at 100Hz.