Piezo mics should go through a very high impedance buffer stage. When I say high impedance, I'm talking 10 megohms minimum. 1 Meg is too low, it basically will act as a high pass filter and your piezo will sound tinny. This page explains all and has a cute 1 stage FET buffer. I have built about 10 of these buffers and they work perfectly, sound great and do not clip:

http://www.muzique.com/news/piezo-pickups/

I bought generic 1 stage buffer PCBs from MusikDing and they keep the buffer circuitry tidy. The circuits, batteries and connectors were housed in guitar pedal/DI style boxes

If you want to tame piezo transients, you can use a small coil. This is what Roland do in those drums pads units - they stick a coil in series with the piezo to smooth out the peaks (a bit like a tiny compressor... ish)

For high-quality sound, don't use piezo - MEAS film contact mics are better.  They are more expensive, but some outfit in Canada sent me a bunch for not much money so not too bad. They are finicky to solder - we're talkin' low wattage irons, lead solder (sorry ROHS) and heatsink clips.

You can also use an active DI box to interface your piezos - one that has a high impedence input. Normal Line level inputs are not high enough impedance for piezos, by the way. I've used BSS DI's on piezos and they sound great. I've also experimented with those cheapo Behringer active DIs - and they sound very good on piezos too. They come in a phantom/battery-powered stereo DI version for about 20 euro - 2 piezos to 2 channels on your desk per DI.     Rich Duckworth Lecturer in Music Technology Department of Music House 5 Trinity College Dublin 2 Ireland

Tel 353 1 896 1500

It's the most devastating moment in a young mans life, when he quite reasonably says to himself, "I shall never play The Dane!"

From: "pd-list-request@iem.at" pd-list-request@iem.at To: pd-list@iem.at Sent: Saturday, 21 April 2012, 0:17 Subject: Pd-list Digest, Vol 85, Issue 61

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1. Re: PhD Defense / Acknowledgement to the Pd-list       (Hans-Christoph Steiner)   2. Re: PhD Defense / Acknowledgement to the Pd-list (Jim Hickcox)   3. (OT) safely connect piezo transducer to soundcard as       microphone (Matteo Sisti Sette)   4. Re: (OT) safely connect piezo transducer to soundcard as       microphone (Martin Peach)   5. Re: (OT) safely connect piezo transducer to soundcard as       microphone (katja)   6. Re: Help with Jack and PD (Michal Seta)

Message: 1 Date: Fri, 20 Apr 2012 09:55:55 -0400 From: Hans-Christoph Steiner hans@at.or.at Subject: Re: [PD] PhD Defense / Acknowledgement to the Pd-list To: Alexandre Torres Porres porres@gmail.com Cc: pd-lista puredata pd-list@iem.at Message-ID: D7F486B1-8D83-405D-A68E-7C6A5C023646@at.or.at Content-Type: text/plain; charset="us-ascii"

Congratulations on finishing it!  Hope the defense went well.

.hc

On Apr 10, 2012, at 12:49 AM, Alexandre Torres Porres wrote:

Hi Folks

I defend my PhD thesis this friday here in Brazil. I'd like to share it with you because this list has always been very helpful, I actually made a remark about it in my acknowledgements. And I also put a special remark to all who were here for PdCon09, that was a great experience for me! :)

My draft text, submitted to the board, is at the following link; https://docs.google.com/open?id=0B3AoiT0xk8fnZThjOWQ3YzUtOGUzYS00NGVjLTkwN2Q... I shall update it though after friday according to the feedback. Then I'll release an official one later one. Wish me luck.

I know most of you can't read portuguese, sorry.

I've used lots of Pd in the research as you might wonder, and there several figures on the text all made from patches. As soon as I get to clean them all along with the text, I'll spread it out over here.

Thanks a lot people

'til next time Alex

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