I'm a little confused by piezo polarity.. I've read that its different from piezo to piezo. I've also read that they are consistent its just a matter of which way they are bent. I had a little time to test the last theory by bending them different ways to produce either a positive or negative polarity and see it on a meter. I think this is how they work. Please correct me if I'm wrong.
Based on the above and the fact that the megadrum looks for a positive first half wave I'm not sure how megadrum users are actually getting it every time with the way the cones/cylinders are sitting on the piezos. My understanding is taken from this picture:
The way I see it is the foam cones/cylinders sit on the ceramic (raised middle) part causing a negative first half wave from the force of the head when hit. I can switch the wires around but the polarity isn't consistent every time.
I thought I can do this, which seems to work on my initial testing last night:
In both of these cases I used a foam circle about the size of the ceramic part underneath the piezo as well.
Does anyone agree with my logic?