Arghh! What a frustrating day! Ok so I took an old computer case and I cut a 12" circle out of the side to use as my reflection plate. I estimate it to be 2mm thick. I used old CDs for my sub resonators. I put 3 on the reflection plate space out equally. Everything else I set up exactly like the Alesis pads. Nada! I had to turn the sensitivity up to 99 to get any reading at all. So I figured it was the three piezo setup. So I took it all apart and put just the single piezo in. Same thing, had to set sensitivity all the way up to get anything. Even tapping the reflection plate had little affect unless I tapped directly over the piezo. So then I did away with the sub resonator altogether, and mounted the piezo directly to the reflection plate. Same result. So then I'm thinking I've got the wrong piezos. Nope, switched one in my alesis pad and that pad worked fine. I'm using 1" high density foam on top. Anyone have any idea what I'm doing wrong? Could it be the metal of my reflection plate?
It would help to see a picture but, I will try anyway. First off, using a sub resonator with one piezo is used to even out triggering. So is using a 3 piezo configuration on a single plate set up. Normally you do not want to do both because they both achieve the same thing by themselves.
Are you sure you didn't damage the piezo elements in any way? What kind of tape are you using to affix the piezo to the plate? You should not be using foam tape. That will not work. You need a film tape or you can epoxy it to the plate.
Don't try taping over the whole piezo as this is no good either. The piezo brass must be firmly mounted to the plate.
Are you sure you soldered your wires to the correct tabs on the jack (don't get mad at this statement, because I have made this mistake myself, that is the only reason I ask.)?
Many people try to do this without soldering at all. Do not try this as it will not work (or if it does, not for long). I'm sorry if some of this seem obvious but I really don't have enough info to help.