The build I'm working on is a semi hollow body. It will have a 1/2 inch inner layer and a 1/4 top layer of ply over a maple core. Can I embed the piezo under the 1/2 ply and on top of the core maple? Ot would approximately 3/4 of and inch of wood be two deep? Just how much wood can you have between a piezo and the outside of a box? Would I still need to use hot glue or chalking?
The attachment below shows that I plan on doing.
It's tough to get the right amount of pressure when embedding and still be able to get to it if needed.
When using contact piezo I usually end up putting them near the neck on the low string side, but it depends on your personal preference. I have 2 in parallel under the bridge on on of my 6 strings guitars, but it's brighter than I like. A guy told me awhile back that embedding a piezo in the neck pocket of a bolt on neck is the best position of all, I'm thinking of trying that soon.
I tend to prefer the rod piezo over the round ones and they would work well in a neck pocket of a solid body guitar or hollow body guitar. I haven't found the best passive circuit for a rod piezo yet and the gitty preamp is cheap enough to not bother. ;)
This is good news. So if I where to embed one under the neck pocked it would be under 1 inch + of wood. My 3/4 should work just fine.
The thought of getting to them if needed may change my build a bit. Using a standard boult on neck I can easily mount one in the neck pocket. I could make the bridge the an access for the second piezo. Cut the wood so the bridge is on it's own island. Unscrewing the bridge from the body I'd simply take out that chuck of wood to access the second piezo. Something to think about.
Yep, I'm responding to my own post. My MO. Make it supper hard and extreme before really thinking about it. OK, lets get back to realism. Take this down a few miles. Re examine the bridge piezo. Under the bridge there will be a hole. In this hole will be a wood plug that will be held in place by the bridge. It will press down onto the maple layer. IN the maple layer there will be a recess with a piezo. Way better and actually doable with my simple level of wood working.
So now I have a guitar with two piezos. One in the neck pocket and the other under a slug of wood hidden under the bridge. I'll have access to both if needed.
Also consider how much pressure on the embedded piezo. Too much pressure will damage the piezo, not enough pressure will dampen the sound. I'd use a couple pieces of scrap to find the right amount of pressure/cavity depth needed before putting it in the guitar.
got you covered. I"m making the piezo hole deep enough to house some soft foam. The wood will press against the piezo. The foam will give underneath. But not deep enough to need more than a thin slice of foam. 1/8 at best. Your idea of practicing with two scraps is awesome! Be doing that before I make the holes.
Like that foam idea. Got any photos of the process?
Nothing yet. I've got a tall CBG that I can retro it in so I'll be able to test for sound. One thing I am planning on doing is to make sure the soldered side of the piezo is pressed against the foam.