do you know Akufen? "glitch" or "microhouse" music based on very very short samples of FM radio
@craigmaloney You can still get similar sounds by tuning in to the digital text parts of any HF ham radio band. The methods have gotten more advanced but the principle's still the same: using sound to represent binary data.
The difference between cassettes and ham radio is only in that we transmit it using SSB transmitters instead of recording it.