Looper's Delight Archive Top (Search)
Date Index
Thread Index
Author Index
Looper's Delight Home
Mailing List Info

[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