[jack_hobday]

Hey everyone,

I'm looking for a bit of help.....

For my major project at uni I am designing a portable pair of headphones which will use PVDF piezo film to create the sound. This is not a technical project but a product design project, though I would like to attempt to make a working prototype.

I've found enough information which will allow me to decide on the parameters of the PVDF film shape and size however my knowledge is pretty basic when tackling the electrics side of this.

My first question is, what is needed (amps/transformers etc) to drive this enough to get a good enough sound?

Are any other electrical components needed?

Is it even possible to make a portable headphones which uses a PVDF film??

Are there any pitfalls I should watch out for?

My main issue is working out how to power the headphones using an mp3 player

All help will be greatly appreciated!

Thanks

Jack

 

[jcx]

the links in the 1st page of:
http://www.head-fi.org/forums/f113/t...3/#post5325079
should lead you to pictures of one pvdf headphone's transducer design

a pvdf transducer needs some way to curve the film to turn the transverse piezo motion into back-and-forth air pushing motion to create sound - there is at least one other method which stretches the film over a foam backing

the detailed transducer design for generating sound will be a big part in constraining headphone industrial design - you will have to assume some minimum physical dimensions, radiating area, thickness, position relative to ear


power is another issue - very high voltages are required and the transducers aren't very efficient - classic step-up transformers aren't pocket protable

 

[cetoole]

The Pioneer SE-700 is a fair bit like you describe, a curved roughly circular piezo film driver, with foam directly providing the tension to the back side. It is actually pretty cool, though needs a fair bit of power. A reasonably beefy headphone amplifier does OK, though other than my 'stats, it takes more voltage than any other headphones in my stable to drive. I would estimate it is in the ~2-3v range when playing at a reasonable volume, though that certainly is not exact. Been too long since I played with it.