Triangle wave
Appearance
A triangle wave is a waveform that can be obtained by subtractive synthesis by integrating (lowpass filtering) a square wave. Like a square wave, it contains only odd harmonics. However, the higher harmonics roll off faster than in a square wave, and so its sound is smoother than a square wave and and nearer to the sound of a sine wave.
It is possible to approximate a triangle wave by additive synthesis, by adding odd harmonics of the fundamental, rolling them off with frequency faster than with a square wave. The infinite series will converge to a triangle wave.
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