contact mics

[soundispatch]

hey all,

i've been researching the logistics of making a contact mic, and it seems a fairly straitforward solder-and-go project, but i have a couple of questions about piezo transducers/speakers.

i am looking for something that will give me a better-than-average frequency range, but i am unsure about what will give me the best sound. i have seen : electro-magnetic tranducers, piezo transducers, piezo 'ceramic' transducers and piezo speaker elements. which is most applicable?

also, not to sound woefully ignorant, but i have found that piezo ceramic transducers come with varying MHz specifications. what is the difference here (for example between 2.5 and 1.6 MHz)?

thanks again,
cal

[psychicoctopus]

I just tried a flexible piezo film transducer from www.windworld.com, and it seems to have a decent frequency range. Very cheap, too. (two dollars!!) But I used it to amplify a gong into a guitar amp, so who knows what that's supposed to sound like?

Have you heard of anybody using the piezo ceramic transducers as contact mics? With a specification of 2.6 MHz, it's hard to judge if it will do audio well.

Piezo contact pickups are high impedance devices, like guitar pickups, so they might sound weird going straight into a mixing board.

[soundispatch]

Piezo contact pickups are high impedance devices, like guitar pickups, so they might sound weird going straight into a mixing board.

yes --- anytime i've used a contact mic in the past i've plugged it into some form of stompbox/pedal. (usually distortion!)