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I'm wading through Gore and Gilet Volume 1 and am curious as to how my first two builds (and the other two I'm working on) shape up with respect to the various Chladni patterns. Was wondering if some of you could share exactly what equipment I need to generate these, particularly how one dials in the various frequencies. Can I get what I need at Radio Shack? Any input or photos appreciated.
Thanks,
Marty

There's quite a lot of discussion about this on the ANZLF site, for example here. If you do a search on that site for "signal generator" you'll find quite a lot more stuff and also more in this section too, if you do the same search there.

There seems to be no simple "kit" analogue signal generator currently on the market; the ANZ guys have searched long and hard. Apps like Visual Analyser have a digital sig gen, which works fine, but is not as easy to adjust as twiddling a knob. You will need an audio amp (10-15 watts works fine for me) and a speaker.

The third and fifth pics down on this thread show some pics of my rig using my old analogue sig gen/amp (the Mini-Lab).

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

There is a freeware program called "Sweepgen" (google it--there are many sources) that can generate audio tones at all audible frequencies. It's pretty easy to use. Plug your computer's sound output into an external amplifier driving a speaker and you'll have everything you need. Hearing protection is good, too.

Thanks, Bob and Trevor, I believe this is what I needed. Really do appreciate your responses With regard to the frequency generator, it sounds like digital may be the way to go (and I've got an extra laptop), but I do like analogue gadgets.

or you could use Gibson's old method of a violin bow rubbed against the edge of the plate.

If you're into wiring yourself, it's not too hard to set up a signal generator. Matt Fichtenbaum made one up back in the late 80s, iirc, and published the circuit as a GAL Data Sheet. Good luck finding it! We made about twenty of those back when.

The real issue is knowing what pitch you're at. A good tuner can get you that, and there are digital frequency counter chips that can be set up for not too much money.

Don Bradley has been making a nice PIC based signal generator for some time now specifically for this. It covers the frequency range from under 1 Hz to 20k or so, with accuracy to .005 Hz, and will read out in Hz, or pitch, in cents. It's got a built-in power amp, about 12W, iirc, and some of the usual engineer's goodies, like the ability to store and recall frequencies. You can get in touch with him at:
Bradley Engineering,
P.O. Box 141
Forestville CA 95436

I'll try to dig out his e-mail.

E-mail addres Don Bradley is <sonomadb at sonic.net>

Thanks, Alan and Edzard. I sincerely appreciate the help.

Don's sig gen/amp is a great piece of kit, but comes at a price - ~$500 last I looked.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au