Thursday, May 22, 2008

Sponge Mic Sound Absorbing Wet Transducer

.....or we could call it a water-coupled transducer. The use of a porous material for a transducer is actually not a new idea. This novelty sponge is made to be used in the bath and appears to be a die-cut piece of ordinary sponge like you have in the kitchen. Sponges can be made of a piezoelectric polymer and can emit sound when excited by AC, or they can act as a transducer, either a pressure transducer, or sonic. The foraminous nature of a sponge makes it easier to acoustically match it to its surrounding sound conducting medium. Water is an excellent and low loss conductor of sounds of all frequencies, air less so, and confined mostly to frequencies below 500 kHz or so. I don't know where I can buy these but you could make your own with a sponge and a scissors. I imagine that a 77DX-shaped sponge would be easy to make, and of course one in the shape of a U-47 might be of interest. How about one shaped like a Shure 55C? That would be pretty cool.

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