Reducing buzz on piezo home-build transducer

[amundsen]

Hello,

I am using these piezo transducers from Maplin on microphone inputs on a Fostex FR-2 recorder. However I have much buzz any time I touch them.

I was wondering whether it was a matter of impedance. I have read somewhere one should connect piezos to High-Z inputs but the FR-2 doesn't have such ones.

So, what can I to improve the situation? Should I insert a resistor and a capacitor as described here?

Thank you in advance.

[EstateMatt]

+1 for this subject. I just checked gear sluts before going out to buy jacks for my discs.

[amundsen]

After additional readings, I think a DI Box could be a solution.

But before buy I would like to be sure there is not a cheaper way to go. Also, what kind (active/passive) and brand(s) of DI is/are better for this purpose? Should I avoid transformers?

[amundsen]

Just found this link...

DI unit: Information and Much More from Answers.com

[BVB]

Hi,

These transducers are no input ,but output devices.
Maybe you can use them vice versa,but they have to be properly shielded.

Greets
Paul

[amundsen]

I know that piezo transducers are used as buzzers but they have been used as microphones for decades too (of course they are much less used nowadays since other techniques have been developped).

However, I note your advice about shielding. How would you proceed with such discs?

[RawDepth]

Originally Posted by amundsen

I know that piezo transducers are used as buzzers but they have been used as microphones for decades too (of course they are much less used nowadays since other techniques have been developped).

...Other techniques like...the microphone?

Why don't you just get some real mics like it was designed for?

I don't think those piezos are good for much in the music world except for midi triggers and such. Granted, they respond to vibration but they don't make very good mics for quality recording. And they break easily.

[BVB]

The only time I have seen them in use was in Turkey on this kemane and it sounded awful (it was mounted under the bridge).

Kabak Kemane (three-stringed violin), Turkish String Instruments.

As for isolation, I think you will have to improvise.

Greets
Paul

[amundsen]

Don't be so dismissive with piezos!

Of course they do not reproduce the full audible range nor they do have a straight frequency response, but that's not the point.

They can be (and are) very useful as contact microphones. Moreover, they are very cheap ( < 1 euros/dollar) and therefore can be used for experimental use in dangerous places. For instance a person I know put them in acid so to get very strange sounds. Personally I plan to use them as hydrophones for instance (of course I will protect them against short-circuits first).

Another project : taping 8 of them on a percussion and spatialize the sound just by moving the hand on the percussion.

One should experiment a little bit to get new sounds, shouldn't he?

By the way, any insight to get rid of the buzz is welcome!

[Saudade]

Originally Posted by amundsen

Don't be so dismissive with piezos!

Of course they do not reproduce the full audible range nor they do have a straight frequency response, but that's not the point.

How to make a Piezo Pickup

Go and build it, hear the truth for yourself

(it tells you about shielding too)