[
Date Prev][
Date Next] [
Thread Prev][
Thread Next]
[
Date Index][
Thread Index][
Author Index]
Re: Piezo mics
>The piezo mic is two thin layers of metal, with a layer
>of ceramic between. Typically 1 to 2 centimeters in diameter,
>and less than a millimeter thick. When the element flexes,
>a tiny amount of electricity is generated.
they react on pressure in the first place. In a lighter, you press on
them and the resulting voltage is so hight that a spark results.
>A pre-amp is
>needed.
the impedance depends on size. Its always bigger for low frequencies,
so a small element for full range needs about 2Megohm input
impedance. If you have a big element and/or dont need the low
frequencies, it can be much lower.
>As far as I know, they work best on large, flat surfaces
>that resonate with the sound.
between an activator and the base they work even better.
>The prime example is the front of an accoustic guitar.
better example is the bridge, between string and body. You can get
several volts there.
>A flute probably won't work.
yes, air movement is not enough, it takes a vibrating hard material.
The tube of a flute vibrates but maybe not enough.
>
>However, what is so cool about them is that they are cheap
>if you make your own, which is pretty easy. Buy the bare
>element, or disassemble a Radio Shack buzzer, attach the
>wires, and you've only spent a couple bucks. Stick it to your
>instrument and see what happens. Try different spots, and
>wire two together for fun. I plan to embed a couple
>inside a hollow body kalimba I'm building.
>
>
>I originally found via Google some long posts from an
>guitar discussion group on the topic, but much instruction
>isn't needed because it is so easy.
>
>Yours in rhythm,
>Steve
--
---> http://Matthias.Grob.org