Title. There are lots of planar-magnetic headphones on the market, but when it comes to disclosing the material for the diaphragm, there isn’t that much information.
I know there are lots of knowledgeable members here, and I wanted to ask whether anyone is aware of a headphone using PET/PETE for their planar driver diaphragms.
I have heard of using Mylar, polymers, Kapton, and even Kevlar as a diaphragm material in planar drivers for headphones and speakers. I’ve never specifically heard of PET being used, but seeing as how it’s a polymer I wouldn’t be surprised at all to learn that it’s one of the polymers being used. I’ve never looked into it much myself.
I do remember a thread on Head-Fi where someone asked why exotic membrane/diaphragm materials aren’t used or mentioned in marketing like they are with dynamic drivers and a member of the trade answering that the way planar drivers operate limits the viability of many materials and also makes it so that much of the imparted characteristics that make them sought after for use in DDs doesn’t apply to any potential use in planars. He gave a long explanation about something to do with traces and aluminized films making the actual material less important as long as it is as thin as possible and able to hold adequate tension or something like that. All of that to say, I’ll see if I can find the thread I’m referring to. I suppose it could have been on Reddit instead of Head-Fi, but I seem to remember to member of the trade tag on the account of the responding poster and that’s only a thing on Head-Fi. I’ll post an update if I find it. 
Edit: BTW, I know that many electrostatic drivers are made with PET film for the diaphragms so that’s another reason it wouldn’t surprise me.
Just a short head up - mylar is just brandet PET. Dupont just named it to have a recognizable name and it got synonymous with PET films at some point.
By the way PET is a good material for membranes because you can stretch it well without it changing its plasticity.
I think in Estats it’s mostly used but that’s just my assumption
Well, there you go. If Mylar is PET then, yes, PET has been used for planar membranes/diaphragms (and electrostatic as both myself and @Pr0Xy noted) as I know that Mylar has been used for manufacturing planar driver diaphragms.
Thank you for such a detailed answer!
For example, one headphone that I found to be stating it’s using PET for the diaphragm is Avantone Planar.
I’m just curious about the materials that are used for diaphragms in planars. We already know that Mylar is pretty much the standard film used for electrostats.