I obtained a Slinky over the weekend and decided to test it out as a sound generator by clamping a piezo transducer at one end and tapping my fingers at the other end as an impulse. As you can see in the video it’s a pretty interesting result.
I also experimented with sending various signals through the Slinky using another piezo transducer clamped to the top, operating a bit like a crude spring reverb unit. The impulses – square and sawtooth waves; recordings of voices and instruments all sounded quite reverberant with (in given cases) slight instances of frequency modulation. (not included in the video)