[sdiy] Re: About this LC filter formula questions

[phillip m gallo]

Glen,

In the late '70's i built a plastic tube based delay line.

ElectroVoice made compression drivers with an aperture on both sides of the
diaphragm.  I fitted two different lengths of tubing, one short and one
long, to the compression driver (don't remember the exact lengths but still
have the tubing and driver in my garage). Each tube was terminated with a
electret mic capsule.

I was able to get some good "hollow room" delay sounds and processing the
mic's separately for both filter and phase (as the tubes are 180 degrees
out) allowed some good variation.

I used the beast live and for recording.  Live was a scream (or howl) as it
could "feedback" if not careful.

regards,
p


>
>Here's a freaky idea:
>
>Build a "tube echo" with a large length of flexible plastic pipe, which has
>been rolled into a coil. Connect one end to a small box which contains a
>speaker. At several points along the pipe, drill a small hole and insert an
>electret microphone into the hole. Connect preamps (probably with some EQ)
>to each microphone. Then use your scanning circuitry to sweep back and
>forth among the various microphone signals. In other words, do the whole
>delay line with sound instead of an electrical transmission line
simulation.
>
>How's that for an unusual vibrato-chorus design?
>
>One thing's for certain, it's sure to have an "analog" character to it.
>
>
>later,
>Glen Berry
>

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