An actual *stomp* box....for stomping

[PRR]

> the cheap black plastic things with a suction cup that would be advertised for recording phone conversations by sticking it on the receiver handset.

Not true contact mikes. A contact mike senses vibration. The phone tap picks up the magnetic field around an old-style telephone earpiece. Good hum-sensors, BTW; perhaps not as good as a single-coil pup but easier to wave around.

Long-long-long ago a contact mike was a telephone mike or earpiece mounted so the diaphragm hit the surface being sensed. Phonograph cartridges make good contact mikes, and were used in a series of roughness sensors for fine finishing. I've used a couple specialized magnetic contact pickups. But since Barcus-Berry, piezos have dominated musical contact mikes. IMHO they range from "ehhh" to awful, and the difference (aside from LOCATION) is loading.

[Nasse]

http://www.soundonsound.com/sos/jan02/articles/synthsecrets0102.asp

Perhaps a deluxe version could be done if using both piezo and small speaker as mic. You could tune the resonance of the speaker cone with small heavy things glued on but some might be just on the range. Low Z input stage must have?

[IGR]

I used small 3-inch woofer loose screwed at piece of plywood, screws dampened with rubber washers, area under speaker have dampened with thin rubber foam.
Speaker can move vertically approximately 1mm. It was necessary to adjust the impedance to common amp/ mixdesk. So I used a small power transformer 230/9V~2W.
Speaker is connected to secondary (9V) winding, at that moment I remembered the schematic of Korg drum machine where instruments are created by L/C circuits.
If the impedance of primary estimate 5H, adding 660n cap parallel creates resonance circuit about 85 Hz. The resulting pickup produces damped oscillations at line level. Decay (or oohmp) depends on amp input impedance, 47k line input I see as optimum.