Waveforms

The frequency, of a sound is only one of several variables which acoustic waves can possess. The other significant factor is shape of the wave itself.The simplest acoustic waveform is the sine wave, in which all of sound energy is concentrated at a single frequency. Sine wave sounds are quite rare in nature. A good instance of a sine-wave sound is the beat note, or heterodyne, generated by a steady carrier in the communications receiver.

In music, almost all the notes are complex waveforms, comprising of energy at some frequency and various multiples, or harmonics. Examples are the sawtooth, square, and triangular waves. An instrument may produce a note at 1 kHz and at numerous harmonics: 2, 3, 4 kHz and so on. The shape of the wave- form depends on the distribution of energy among the fundamental frequency and the harmonics. There are infinitely different shapes which a wave can have at a single frequency like 1 kHz. Music comprises many different tones which intermingle to make the overall waveform unfathomably complicated.