BillFitzmaurice.info

What's the official Duratex site? I want to see the international distributors.

Well, I remember someone told me that the Pyles once had a better quality control, maybe it's specific to those, I don't know.
But with the price of Piezos, I think I'll still order a bunch of spares when I make other projects, even if these won't be Pyles.

Don't pass on the mic test. I did and later had to take all of the piezos from my 4 DR250 and to rematch them. On some Piezos you can hear the annomalies, on the others you don't. They might differ in level and impedance (IIRC), not just frequency response, so it might sound ok but overall a few bad...

A non scientific way of doing it: Get a few more piezos because it might be that some won't be usable. Get a nice mic, preferably omni, place on stand. Make something to put each piezo on (in turns), and place it in front of the mic about 1m away. Get a recording software that has a frequency analyz...