Sound machines

[Mike(Mont)]

In the early 1990's Bill Morgan can out with the Soundwitch which was a piezo tweeter (4.2 Khz +- a few hundred hz) used like a frequency generator. This is exactly the same as the colorado gold sticks sold on ebay that claim to be "bran new" (biggest piece of crap ever to hit the LRL market). You can build your own for about $5. from Radio Shack. Morgan also said you can hook up a loudspeaker to a frequency generator to get a much more accurate unit. Or add a small amplifier like they use on ipod or mp3 if needed. Morgan said you can hear a slight difference in the tone when you cross the signal line. More later.