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Permalink Reply by Kevin Sprague (Knotlenny) on August 18, 2009 at 3:08am

Some tried and true methods to reduce feedback, minimize handling noise and the shrill response of piezos include -

1- Make sure they are mounted as close as possible to the underside of the bridge.

2- Immerse them in a blob of hot glue - and/or sandwich them in some spongey material (such as a mouse pad)

These approaches have worked pretty well for me. An even better way to deal with it is to construct a bridge itself with the piezo sandwiched into it.

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Permalink Reply by Ben on August 18, 2009 at 3:11am

Yeah...feedback does not equal a shielding problem as far as I know...

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Permalink Reply by J. K. on August 18, 2009 at 3:32am

Correct me if I'm wrong here...
Shielding problems is mostly connected with coiled pickups if and doesn't effect piezos all that much because you have a lot less lengths of cable that can pick up on the interference. Shielding problems normally manifests itself as crackling, hums and whatnot from outside sources. Sorta like having a wall-wart or any power supply close to an audio or video cable.

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Permalink Reply by Jkevn on August 18, 2009 at 9:13am

All of us are guilty of using the word "shielding" in more than one context. Usually it is used in reference to blocking electrical interference from jumping in on unprotected connections, wiring etc.
Here we need to "shield" the transducer from unwanted vibration. When the string vibrates the transducer it creates a signal that's sent to the amp, juiced up and sent out through the speaker. What comes out of the speaker can then vibrate the box lid or the piezo itself and create an endless loop. Mounting the piezo in a blob of silicone, hot glue or the like, and making sure it has a generous helping covering it will help keep those stray vibrations from getting back on the bus for another trip round the block.

If your piezo is already glued in, you can try covering the exposed part (inside the box) with pieces of mouse pad, silicone, or hot glue to cut down on that dreaded squeal. Luck

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