[Mark F]

I need something to allow me to hear the presence of high frequency
sounds.

In particular, I need something to either shift sounds about 10KHz
down or cut their frequency in half.

For example, I want to be able to analyze engine sounds, CRT flyback
sounds, turbulence in water and air flows, etc.

I can't just use an oscilloscope or similar graphics device because
the differences between a good and bad flow is usually too subtle to
see on a video display. (I only need for the device to work at up to
about 22KHz; I don't need it for communication with bats or dolphins,
so I don't need for it to work in the 100KHz range.)

Since I need for the response to be in real-time I can't just find an
analog tape recorder and playback at half speed. (Also, since the
response has to be in real-time there will be frequency palliating.
This is acceptable.)

My budget for the complete device, including microphone, is $300.

I tried Google and found "eConvergence's Belfry Bat
Frequency Division Detector" at
http://njsas.org/projects/bat_detector/01/belfry.html

This might do what I want, but it is do-it-yourself. I want an off
the shelf device.

I also found some MIDI things that might do what I want, but they need
a MIDI studio to work with, which puts it out of my price range.

Does anyone have any suggestions for a specific device or technical
term? (Searching for either "frequency shift" or "frequency division"
didn't help much, since there were too many hits for uses unrelated
to my use [except for the Belfry Bat detector, which I found among
500 other hits.])

Thanks.
due to

[Matt Ion]

Mark F wrote:

Does anyone have any suggestions for a specific device or technical
term? (Searching for either "frequency shift" or "frequency division"
didn't help much, since there were too many hits for uses unrelated
to my use [except for the Belfry Bat detector, which I found among
500 other hits.])

How about a guitar/bass pitch-shifter pedal?

http://behringer.com/UO300/index.cfm?lang=ENG
http://www.bossus.com/index.asp?pg=1&tmp=22

Just for a couple... should be able to find them retail for well under
$100.