How much foam under piezos?

[OldNick]

Hi ~ me again,

One other question (then promise I'll lay off for a bit)... Have read that putting too much foam (double sided sticky) under the piezos {edit ~ on x-bar mount of reglar eTom/snare set-up} can make them too sensitive / give a harsh sound etc, so some people recommend just mounting with regular double sided thin tape. What are the symptoms of not having enough foam under your piezo..?

As I type this I'm wondering if the answer is just going to be "they're not sensitive enough" so apologies if this is a dumb question. Are there other reasons for low sensitivity... what symptom would have you setting off to put more foam under? (have seen mention of double layers of foam tape). Just asking 'cos I've haven't picked up on this in reading through many threads.

Any thoughts much appreciated
Nick

[bogiesbad]

I use two layers of foam tape. I have two drums with only one layer that work fine but use two now....never tried any other way so don't know about those results...I would think dynamics would suffer most as the piezo has no room to flex. Be sure to cut the tape the same size as the ceramic (smaller than the OD of the brass) but mount ceramic side up.

[daveybabes]

Yep

Cut to the size of the ceramic as to let the brass edges ring ... that's how Roland do it.

I use the extra wide tape, i take a washer the same size as the ceramic part of the piezo then i press it against the tape to make an imprint then i cut round it with scissors.

I tried no tape and lotsa tape, couldn't see much difference.

[jammin777]

what is the advantage of using 2 layers of tape on the cone piezo? also use 2 sided tape for the rim piezos, ? does placement matter? i will try using 2 rim piezos?? im diy-ing keller maple shells 3.5 x 10 and 3.5 x 12".

[JmanWord]

As mentioned above the double layer of tape lets the head piezo flex. Another thing that is important about this is Positional Sensing. If the tape is thin and the piezo edge leans or somehow touches the platform .... Pos. Sensing is screwed up....

[mystic fred]

the rigidity of the bar the piezo is mounted on affects sensitivity, the only way is to try different thicknesses/sizes of tape till you find one that works well.

[JmanWord]

For most designs the only thing that should be flexing is the foam and piezo.

[jammin777]

thanks! now i understand. now wheres my tape?

[OldNick]

Thanks for the info guys, will all help to steer me along the journey to my first diy drums (now where's that RSJ for the x-bar???)
Nick

[SuperPuss]

I just finished my first mesh DIY on a 13" tom I have and, thanks to the advice of everyone in this thread, I mounted the piezo to the crossbar so the double sided foam tape is only the width of the ceramic part of the piezo, allowing the edges to flex. I used a single layer of foam tape but this tape is quite thick.

Although I am using this as a tom, once I got it all together, I plugged it in to my snare input out of curiosity and the positional sensing is working perfectly
I used square aluminium tubing for the crossbar and ran the wires along the inside of it to keep them hidden.

I took photo's of each step (including the cutting of the tom shell in half) and posted them HERE

[OldNick]

Hi, just looked at the pics ~ looks great!!!

Can't wait to get started on my project now, need to get the rest of the stuff ordered and then get to work.

Nick

[SuperPuss]

This DIY stuff is totally addictive Nick

[Sabre]

try different thicknesses/sizes of tape till you find one that works well

And don't cheap out on the double stick foam tape.
I used some stuff I got at the dollar store, but after a few weeks one side would collapse and put my whole sensor assembly off kilter.

[JmanWord]

And don't cheap out on the double stick foam tape.
I used some stuff I got at the dollar store, but after a few weeks one side would collapse and put my whole sensor assembly off kilter.

I agree. I was using Duck brand 2 sided foam tape a couple years ago and because it is softer than 3M brand the Duck stuff would compress sometimes on one side and cause what you mention.... Never a problem like that with 3M though.

[freddarl82]

I agree. I was using Duck brand 2 sided foam tape a couple years ago and because it is softer than 3M brand the Duck stuff would compress sometimes on one side and cause what you mention.... Never a problem like that with 3M though.

Hear! Hear! I couldn't agree more. I was about to say, the best discovery I've made in DIY is to NOT use the Duck brand and buy 3M instead. I've always believed in using 3M products when doing painting projects around the house, but for some reason decided to use some old Duck-brand doublesided foam tape I had laying around for my early DIY. The stuff was impossible to work with - WAY too sticky (ruined a few piezos trying to move them) and difficult to get the backing-paper off. I also noted the "leaning" tendency. Finally ran out of the Duck stuff and bought some 3M. Wait a minute...is it supposed to be this easy?!?