Square Wave; Pulse Wave - Alesis Fusion Tutorial

ALESIS FUSION

Square wave

The square wave is another very bright waveform but sounds different because it only contains
odd numbered harmonics (X3, X5, X7, etc.). As a result it sounds 'hollow' and not unlike a
clarinet. It is useful for many sounds that require that quality and is very useful for reinforcing
bass sounds, especially when tuned an octave down from the other oscillator(s).

Pulse wave

The pulse wave is a bit of an exception because the width of the pulse 'spike' can be
continuously varied and the distribution of the harmonics changes according to the width of
the pulse. When the pulse is very thin, the sound is thin and 'nasal' (like an oboe) and gets
fuller as the width increases. The pulse wave is good for clavinet-like and other thin sounds.
If you change the pulse width whilst it is sounding, you will hear a pleasing change in tone not
unlike a chorus effect and if you use some controller to do that automatically, this is called
'Pulse Width Modulation' (or PWM) and can be useful for creating thick, ensemble textures as
we shall see later.
Triangle wave
The triangle wave is not unlike the square wave in that it only comprises odd numbered
harmonics. However, the harmonics are very much lower in level resulting in a more mellow
sound that is suitable for pure and simple sounds.
Sound generators
ANALOG SYNTHESIS TUTORIAL
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