Homebrew Drum Computer Delay Lines
bnansel at bigpond.net.au
Sat Dec 15 18:34:11 CST 2007
I've come across a reference to a reverb unit made with a garden
hose, speaker, and microphone. Would something as bone-headed as
this work as a data delay line?
I've read that mercury was used in delay lines because it was a
better impedance match with quartz transducers, but wouldn't water
work nearly as well? Everything would need to be kept at a constant
temperature, and no doubt there would be some dispersion of the
compression waves. It's my understanding that a lot of materials
were tried for delay lines, but that mercury was the "best."
Magnetostrictive delay lines are attractive, though I hear they are
more than a little microphonic. I notice that most magnetostrictive
delay line designs use the transducers to generate torsional waves,
which apparently suffer less from dispersion and have a slower
propagation speed to boot. The pictures I've seen show the
transductive materials spot welded to the delay wire such that they
twist the wire when a magnetic pulse is applied:
Does anybody know how well plain nickel wire would work OK, or would
some more exotic like Terfenol-D be required? The delay wire itself
need not be magnetostrictive; it's just the storage medium.
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