Any tips on the best practices for mounting a 15mm piezo bender to achieve maximum sound output?
Is it as simple as using a very thin bead of silicone at a radius of 0.65*15/2 = 4.9mm?
I should have bought two of them.
What's a piezo bender? Do you mean a piezo buzzer or beeper? It depends... Some are soldered to a PC board, some have holes for screw mounting... Do you have a link to the datasheet?
A piezo bender used as contact speaker should be glued rigid to a hard surface.
The surface acts as soundboard.
If you use silicone, you will dampen the sound.
Just connect it to a headphones output, and try.
Leo..
DVDdoug:
What's a piezo bender? Do you mean a piezo buzzer or beeper? It depends... Some are soldered to a PC board, some have holes for screw mounting... Do you have a link to the datasheet?
http://www.mouser.com/ds/2/334/PUI%20Audio_AB1541B-LW100-R-341213.pdf
Wawa:
A piezo bender used as contact speaker should be glued rigid to a hard surface.
The surface acts as soundboard.
If you use silicone, you will dampen the sound.
Do you mean glue the entire circular area to a rigid surface? What sort of glue?
Is this all wrong?
.
Mounting
Producing the desired sound output is an important design consideration for a piezo bender. To effectively propagate this sound, correct mounting of the bender along with matching the resonant frequency is two of the most important aspects of bender utilization. A resonating chamber can also be designed and constructed to increase the SPL.
A piezo bender has a resonant frequency where, when mounted properly will result in its highest SPL rating, when the resonant frequency is used.
There are two ways to optimally mount a piezo bender, nodal and edge.
Mounting a piezo bender at its nodal point (circle) results in the lowest bender impedance, a resonating frequency that matches the open-air resonant frequency, narrow bandwidth and highest sound pressure level.
The nodal point is found by multiplying the base diameter by 0.65.
For example: If you have a piezo bender with a 20mm base diameter, the nodal point will be 20 x 0.65 = 13mm. The nodal point will be a circle 13mm in diameter centered on the base.
Mounting a piezoelectric bender at its edge results in higher bender impedance, broader bandwidth, lower sound pressure level than nodal mount, and lower resonating frequency (64% of the open air resonant frequency).
For example: a piezo bender with a resonant frequency of 2.0 KHz in open air will have the following resonant frequency when edge mounted:
2000 Hz x 0.64 = 1280 Hz
This will allow the bender to flex in a more restricted fashion than nodal mount, but still produce an acceptable sound pressure level as illustrated in Figure 3.
In using either nodal or edge mounting, an adhesive that when cured remains soft and pliable is necessary for maximum sound pressure level output. A silicone RTV is what is generally used in the audio industry for piezo bender mounting.
The adhesive must be a 360 degree ring to allow even flexion of the bender during operation.
The suggested adhesive bead size is 0.060” (1.5mm) in width and height. This will properly support the bender during operation with minimum surface area of the bender plate secured with adhesive.
[www.digikey.com/Web Export/Supplier Content/PUI_668/PDF/PUI_PiezoBenders.pdf](http://www.digikey.com/Web Export/Supplier Content/PUI_668/PDF/PUI_PiezoBenders.pdf)
Ahh, you want maximum sound at the resonance frequency of the disc/chamber/soundboard.
Not just "sound" (music).
Then that story is correct.
Some benders have a third wire for feedback.
Look inside an old smoke detector for a piezo resonant chamber.
Leo..
This one has just two wires.
I only want it to make an annoyingly loud BEEP. When I tested it I found that the sound is, in fact, quite annoying. It didn't even occur to me that it would be any good for producing music. I might try that just for fun.
Thanks.
It can even be used as microphone.
Watch this.
Leo..