White
noise

THX sound system fanfare:
The Audience Is Listening

Richard James' face at the end of
Aphex Twin's [Equation]

A spiral at the end of
Aphex Twin's Windowlicker

A close-up of the face in Aphex Twin's Equation shows that the image is
made up of discrete, evenly-spaced frequencies ("scanlines")

Nine Inch Nails - The Warning

Venetian Snares - Songs About My Cats

Regular radio emissions of a pulsar converted to audio [YouTube]

Radiation of Saturn's rings converted to audio [YouTube]

The mating call of a male cicada

The buzz of a mosquito

1970's police siren

Playing scales on the Theremin