Fluid-based delay?

[Mark Smart]

In a somewhat related vein, there is the Cooper Time Cube. I used to work
at the University of Illinois Experimental Music Studios where they had one
of these. It's a box with two clear plastic tubes and some transducers in
it. At each end of each tube is a transducer. An incoming audio signal is
converted to sound by the transducer at one end. The sound travels through
the tube (which is coiled up for more length, I think) and comes out the
other end, where it is converted back to an electrical signal by the other
transducer. One tube has a delay of 14 ms, and the other is 16 ms. By
cascading the two tubes together, you can get a total of 30 ms!
The delay times are not adjustable, but you can create repeating effects by
feeding some output back to the input. I never actually heard this thing
get used, but from the manual I looked at, it had pretty good frequency
response characteristics. This was invented by some professor at U of I in
the late '60's, I believe.

How long did the tubes have to be? Well, sound travels at 1100 feet/second
so 1100(0.014)=15.4 feet.


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*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
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