Build log, exploration and experimentation with my DIY Planar Magnetic drivers/headphones.

  1. WaffleIron
    A preface into what this thread's aim is:
    This thread will be somewhat of a build log, but will likely just initially start off with a collection of ideas and experimentation, and It'd be great to get your ideas and opinions on them. I don't have any training in pretty much anything in relation to this other than some high-school material design courses, and a few months experience with headphone modification. I expect to make some mistakes, so maybe anyone else who has the same idea won't have to. If you can see I'm getting something obviously wrong, lemme know.
     
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    So, my main focus is the driver. Although housing and tuning is incredibly important, none of that will mean anything without the driver being functional. My thoughts are kind of being inspired by Audeze and Hifiman drivers. So far it seems I'll be using neodymium bar magnets in a striped pattern. I was originally looking into Mylar and other materials for the diaphragm, but I was then given some advice that Dupont Kapton Polymide tape is the way to go. So far I've been looking into it, and it's quite expensive to ship to Australia, but I've found a couple local retailers that look promising.
     
    I'd stick some aluminium film to the adhesive side of the tape, and draw on a pattern for the traces, and use aluminium etching to get the trace on the diaphragm. I'n not sure if just generic kitchen aluminium foil would be the right material, or if there are more proper, thin industrial options. I'd assume the latter, but I'll probably give both a try. Ferric Chloride should be the right solvent, but actually marking the area to not be etched is the real issue. I'll either just go with a ruler and a sharpie, or create a sort of stencil out of some thick paper card. I've got tons of room for experimentation here so I'm not too worried.
    Ideally, the diaphragm size would be about 100mm. Similar to Audeze drivers. Larger driver just means its easier for me to work on and conceptualize. Maybe on a second attempt I'll try and make a more portable/lightweight planar, provided the first attempt works. Might even go into more 'ear shaped' housings if I get this to work well.
     
    At the moment, my main queries are how to attach the diaphragm to the rest of the driver. Although it won't be under significant tension, it will still be moving. Just trying to figure out the best adhesive that I don't have to re-glue every five months. The ring that I'll glue the diaphragm onto will probably be fiberglass or something similar. It needs to be rigid and flat, so fiberglass being a common PCB substrate seems like a good idea. Gimme some suggestions though if you think otherwise.
    I was also given advice that tension is real important. More that I need to get it as even as possible, not actually under huge tension. I'll experiment a bit here, and probably do quite a few 'batches' of diaphragms and see which measures best, and which two are the most identical. 
     
    I'm currently working on some diagrams that I'll post here when I'm done.
     
  2. ForceMajeure
    Subbed
     
  3. WaffleIron
    Alright, so finished with the diagrams of the magnet array, and the diaphragm trace.
     
    ArrayDiaphragm.jpg
     
    Magnet array is fairly simple at the moment, in the future I may buy some more different lengths so I can get more of the whole diaphragm under the magnets. I'm just going for a more basic design currently, as it's easier to mount them in place that way. Traces are also fairly thick. This is due to my limits being hand tracing/stenciling. I'll be experimenting with a bunch of different thicknesses and shapes, and seeing to what limit I can get to.
     
    I'll work on a diagram of the housing itself soon, though it's not really too important. It will probably look quite similar an Audeze housing, potentially with a bit more soft/round edge to them, somewhat like the Kennerton Odin.
     
    At the moment I can't really actually do anything, as I'm waiting for everything to come in the mail.
     
    Quote:
     
    Appreciate it.
     
  4. Daemon Ursus
    Working on something like this myself, if I can help, I will.
     
  5. WaffleIron
    Awesome. Feel free to post here if you want. It'd be great to see the results of others doing the same thing.
     
  6. WaffleIron
    Just noticed that my lambskin for my pads have came in the post today. Not too interesting, but I've not got much else to talk about. So soft and smells so much like a nice new couch. Will probably make a test pair of pads before I attempt the larger ones when the planars are done. Will post pics if I get around to it.
     
  7. WaffleIron
    Sorry for the lack of updates. Just waiting for everything to come in the post. I've got my magnets and Kapton film. All I need is the thin aluminium to get started on prototyping the drivers. Still not quite sure as to how to mount the magnets. I'm considering doing 3d printing, but I'm not sure how expensive that'll be. Drilling through the magnets would be ideal, but I doubt that they'd not break. Some aluminium with grooves cut out might be how I do it. Any advice here would be fantastic. Some magnets have already broken just from me handling them, but with small brittle neos its kinda expected. I ordered more than I needed so it isn't really an issue. Need to find PCB substrate for cheap but that shouldn't be an issue, as well as the fact that there are other various options.
     
    Didn't end up making test pads from lambskin. I tried sewing it and it is easy enough to just do it when I need to. Prep would be wasting materials. Also, if anyone knows where to get memory foam for cheap in Australia let me know. Clark Rubber is quite expensive and have a minimum size way too high for my needs, and everywhere else online doesn't seem to have it.
     
    Also, I've realised I haven't mentioned it, but these will be closed back planars. Probably extremely similar to the Audeze LCD-XC series in terms of size/shape/design. Who knows about sound. Maybe afterwards I'll do open back. I just need closed back due to current isolation needs.
     
  8. MuZo2
    Anything new on your project?
     
  9. WaffleIron
    Nothing particularly interesting. I've just had it on the backburner recently whilst working on other projects. I'm at the point where I need to make the support structures, which shouldn't be hard. I've just been lazy.
     
    Last edited: May 24, 2017
  10. rellik
    Hey, I noticed you were looking into Kapton. Another film is Teonex. Similar to Tegaderm bandages used in hospitals. Different but will be less prone to Krinkle sound and Krinkle memory.

    Various densities, flexabilities, thicknesses are available

    Often it is used in conjunction with or part of a Tyvek HomeWrap building vapor barrier. Newer buildings may just use Tyvek.

    EDIT: Tyvek is a very spongy materal like styrofoam...mmm
     
    Last edited: May 23, 2017
  11. WaffleIron
    I'll keep it in mind if the kapton doesn't work out. Hopefully it isn't too expensive to acquire here in Australia.
     

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