So firstly I live on an Island, I get my supplies from e-bay, and it takes a month or more to get it here. So I'm not looking for a "go buy one" answer.

What I want to do is make a violin bridge pickup using multiple Piezo elements. It is inspired by a drawing I found, probably of a Barbera. enter image description here

it looks to me like their are 4 Piezos wired in series.

1.) First question: I have some "12mm Piezo Elements Sounder Sensor Trigger Drum Disc + wire copper" are they suitable?

2.) Are Piezos directional? it looks like they are perpendicular to the face of the bridge; does it matter? It would be much easer to glue them parallel to the bridge.

this was my first prototype:

enter image description here

I cut the discs into rectangles; first I stuck them to a bridge to prove the concept, then cleaned up the long cables, and glued them to a bridge and sandwiched them between a thin peace of wood (with a cavity for the solder bumps).

It sounded good, but very hot (loud) I guess because they are in series the voltage (signal) increases for every one added?

3.) I also had a wicked hum! Obviously a shielding problem, any suggestions?

4.) last question: I have heard that having reversed polarity is a "good thing" what is that all about? I think that the new generation of Barbera bridges have 8 elements, one on each side of the string, and their polarity is opposite. This is just a guess..... anyone have anything productive to say about that?

Thanks for your time, excited to start on version 2.0

You have quite a few questions there (and we really expect just one in a post) - but in reality they come down to two:

  • Questions 1 and 2 you have kind of answered yourself: they work, so yes, they are suitable
  • Questions 3 and 4 are inextricably linked: if it's a 50 (or 60Hz in USA) hum then you are picking up EMF interference from your mains electricity supply. Having opposed polarity has a similar effect to the wires in a balanced cable. It allows you to accentuate the signal and (mostly) cancel out noise. See for example humbucker pickups for electric guitars.

As these are piezo pickups, you want to cut out all EMF if possible, which is why the Barebera pickups have 2 opposed pickups for each string.

  • Thanks for the answer. I have sorted the EMF with shielding cut out of a high end data cable but, I am still unclear on the opposed polarity concept. There is is no magnetic field, so what exactly is in opposition? – Electroviolin Apr 1 '17 at 19:07
  • There is a magnetic field - generated by your house wiring. – Rory Alsop Apr 1 '17 at 19:42

enter image description here

May be this could answer your number 2 question hope it helps

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