5. Waveshape
All sounds which the human ear can interpret are never simple. The previous diagrams have been simple sine waves and are usually only ever heard when generated electronically.
These "pure tones" consist of energy of only one frequency whereas every other non simple wave forms which you hear every day will have many different wave forms. These varied wave forms are what give texture and depth to the sounds that you hear. Besides the sine wave, the other wave forms which are commonly used in sound technology are Sawtooth, Square and Triangle which are shown in the diagram below.
(www.answers.com/ topic/sawtooth-wave)
These graphs represent amplitude against time.
As these waves all have different characteristics, they are used for a variety of different sounds. Click on the buttons to hear an example of the sound of the waves. They are all at 440hz, with matching input velocity.
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As mentioned in their description, the waves all exhibit a fundamental frequency, otherwise known as the first harmonic. Other harmonics can be seen if plotted along a time axis. These harmonics are what give each wave their unique sound and ultimately, their uses. It is worth remembering what the shapes of the waves look like as the vast majority of input devices, for example keyboards, will create these sounds using oscillators.
There is another waveform which is sometimes used for studio applications. This is known as "white noise". This waveform is a random signal created by an oscillator and obviously sounds horrible to the human ear. However, it can be mixed with other signals. As the intensity of this wave is the same at all frequencies, it is often used for testing applications.
NB - Sine is sometimes referred to as sinus.