DIY contact mic experience? any luck with headphones?

Has anyone made any contact mics using headphones? I have some fostex rp-20 and sony md-xxx. these are pretty flat as headphones, I am not sure what would happen the other way around.

I am trying to tune panel resonators for acoustics so it should be somewhat acurate, enough to tell me the peak of the resonating system.

thanks.

PS, fixing some horrible acoustic has kept me away from electronics, I thought electronics had alot of voodoo, man, Acoustics is a Black hole!

I tried this when I was about 14 or thereabouts. It did not work well at all!

What about using a cheap piezo to a preamp?

Piezo contact mics are popular and work well in some ways, although I hate the sound of them for acoustic guitar.

I suppose it depends on exactly what you want to use it for.

Seems the simplest way is best and cheapest. I just felt the f-cker with a finger while I swept freq. Who knows, with room modes the reading by any trnsfucer will probably be all over the place anyway.


I'm gonna try the headphone thing sometime for "custom" (read bad) sounds.

I read of a studio doing this with piezo contact mics to tune their panel absorbers, I think it was on the john sayers acoustic forum.

I'm sure your idea would work well if you could somehow mount the magnet indepentant of the panel, leaving the diaphram free to vibrate with the panel. An easier option would be to use a cheap piezo element, say out of a RS buzzer, and attach it with a small spacer to the panel, then leave half or so of the element overhang so that it tends to flex when the panel vibrates.

Not sure that it would produce much output at low freq. though.

on second thought why don't you take your phone driver, glue it backwards, magnet side on the panel and hot glue some form of weight on the diaphram, not to much that it makes the VC scrape, probably even just the glue would be enought.

Haven't tried this myself though, let us know how it worked.

Erik

Thanks Erik, I've been lurking there for the past month (Slayers) -they don't go into detail about mics or electronics though. I saw that a page on a DIY RS contact mic but there was a coment that said the frequency response was crap.

maybe I'll get a Korg CM100 -it's $12. I just thought there would be a cheap DIY way what someone may have done before with good results