Drone and ambient music can be achieved using slowed-down sound layers. Terry Riley for instance used tape loop techniques to create hypnotic music.
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As he stated :
"So, essentially my contribution was to introduce repetition into Western music as the main ingredient without any melody over it, without anything just repeated patterns, musical patterns."
Although in the age of digital music a cassette walkman appears to be obsolete, it may be used for musical purposes. Precisely, if it is possible to mod it in order to slow down the motor speed we can obtain pitch control on any cassette.
For the purpose of this mod, I found a Sony WM-EX314. Luckily, the walkman’s schematics are available online, so I could identify where I could solder a potentiometer in order to regulate the motor speed.
On this particular walkman model, there is already motor speed control through a tiny potentiometer that can only be operated when disassembled (component RV601 on the schematics beneath).
I had to desolder the existing potentiometer and solder three wires instead in order to add an external, bigger one.
This cheap hack is questionable : why bother adding pitch-control to a walkman when one could record slowed-downed sounds directly on a cassette ? Or juste use samples instead ? Maybe because this feature is a treat on 4-tracks cassette recorders. This knob allows tuning and control on a wide range of sound sources.
The result can be viewed online in the following video :
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The following link is more generic, check it out : Primer: Pitch-Bending a Walkman