Non-sinusoidal sources still produce audible sinusoidal partials.

Evidence

The siren played a key role in removing the umbilical cord that connected pure partials with pendular (sinusoidal) motion. It was a revelation that the extremely nonsinusoidal successive puffs of air pressure from a siren still produce upper partials that a trained ear can hear out as sinusoidal, ringing as true as if from a tuning fork. The physical fact that the partials were there but the disturbance creating the sound was nothing like a sinusoidally vibrating surface led Ohm to a new framework for understanding periodic sound in terms of Fourier’s theorem. — Eric J. Heller, Why You Hear What You Hear- An…, 2041

Categorization

• XREF: Connects to the Fourier analysis groundwork in earlier chapters of this book on wave composition.