This is a sound or signal generator with one oscillator. It can play custom wave form so you control the number, direction, amplitude and sharpness of the peaks. This instrument clearly demonstrates the physics of the sound and most importantly you can see that humans do not hear frequencies but amplitude acceleration (or peak sharpness). Also the peak position or direction inside the sound wave has no impact of human perception for the sound. You can even hear 0.2Hz sound of the peak is sharp