DIY Planar magnetic heapdhones in details

  1. Garuspik
    Hi! It's my first post on this forum and I would like to start a thread where I'll tell you my story of building full size planar magnetic headphones.
    Fankly speaking, I'm rather new in Head-Fi (but not new in Hi-Fi [​IMG] ) and I hope to hear your opinion (and maybe some tips!) about my work. I've started building headphones exactly 1 year ago and now I think I have something interesting to tell to the world.
     
     
     
    What are my goals?
     
    1. To build a full size open planar magnetic headphones
    2. Achieve a sound of a really high level ( my landmarks are Audeze LCD-3 and Hifiman He-1000)
    3. Headphones should be ready at least for a small series
    4. Net cost 100-150$
     
    So the story begins...
     
    My first step was to make a simple planar magnetic transducer. From my point of view starting from the beginning with building a headphone is a really bad idea. I'm not novice in making non-dynamic transducer: i've already built electrostatic and plasma speakers, so making an isodynamic speaker wasn't a difficult task for me. I went to market, bought same magnets, opened Corel Draw, made simple drawings and cut with laser a few plastic and metal parts.
    Next day I received such result :
     

     
    And same speaker with one sided magnet system:
     

     
    If Admin will consider my post worthy I ask to move this thread to DIY forum. As a novice I can only start a new thread in "Introductions, Help and Recommendations"
     
    GREQ likes this.
  2. WaffleIron
    Hoo, that's really cool. I'm currently in the process of working on my own planar headphones and have a thread up for them. Progress isn't nearly as fast as yours though. Hope something interesting comes outta yours. Will be watching.
     
  3. Garuspik
    Wafflelron, hi! I read your thread and you made a mistake in tracing diaphragm
    So let me explain how I did those mini speakers and I'm sure you understand about what I'm talking about
     
    Step 1:
     
    Tracing diaphragm
    eec7ac116751.png
     
    Please look, current in all 4 groups of traces flow in the same direction.
     
    Step 2 - placing magnets between group of traces. How I made it I've shown on picture.
     
    Step 3 - making a housing. That's the most simple. Just draw anything you want in any vector editor and cut it with laser.
    b0089032b036.png
     
    Gray details are from steel, purple are from plastic.
    If somebody is interested I'll explain how to make a membrane with conductor lines, what material should be used and how to assemble this.
     
    rikk009 likes this.
  4. WaffleIron
    Yeah I had realised that shortly after posting. Never got around to fixing/updating the thread. I've made an updated trace already. I don't have a a laser cutter, but I have access to a 3D printer at one of the courses I'm taking. I've just been real busy so making the housing hasn't been on my priority list. My real problem at this point is making the headband, but even that is a solved issue at this point, as I have an old Beyerdynamic style headband I can sacrifice. 
     
    Thanks for the advice though. I'd surely be interested in what materials you've used though. I'm using Kapton film for mine, which I've never seen used before. I was advised to use Kapton over Mylar, but I may do a version of both.
     
  5. Garuspik
    For membrane I use Dupont Pyralux. It's some sort of kapton + copper. I've achieved 0.15 width of trace.
    Here photos of my first headphone prototype.
    post_2532_1460129528_e6003d1341152a2443275c24b31ca771.jpg
     
    post_2532_1460659714_5a29a982aa3cdd5b7523678eb25b12fa.jpg
     
    post_2532_1460659759_6a74413fd5e41c3a95048fc93b106264.jpg
     
    post_2532_1460659804_208ed610d371dd5deb921ed371839a36.jpg
     
    post_2532_1460819732_7ea2fc0895ec7e44ea4cd5eab1550849.jpg
     
  6. Garuspik
    Made some measurements of this prototype:
    a3912101c57c.png
     
    For a made-in-evening prototype with magnets bought in nearby store and one sided magnet system it sounds really well and I decided to order custom magnets and build a serious headphone transducer. If someone is interested I'll tell what I achieved and explain how it was made.
     
    rikk009 likes this.
  7. ForceMajeure
    Awesome work.
    Please explain the whole process once you receive the new magnets. How you etched the thin kapton film and so on...
     
  8. Garuspik
    I've already received custom magnets. Frankly speaking, this project started rather long ago but it's not interesting to post everything in one day :wink:
     
    So, before I've ordered custom magnets I've visited my local hi-end headphones store. I took with me my favourite music, screwdriver [​IMG] and whiskey (to an owner as a 'thank you' for possibility to open hi-end planar headphones and look what's inside.
     
    I've listened and opened to look inside Audeze LCD 4, Hifiman He-1000, Hifiman He-560, and some less pricy Fostex. I noticed that all mentioned headphones has relatively small membrane compared to the size of the cup. I consider this to be a huge mistake in their construction. Let's change this! I've tried to maximize moving area of membrane and draw such thing:
    2.png
    Outer diameter of cup is 110 mm. Diameter of the moving part of diaphragm is 82 mm. That's about twice as big in comparison with He-1000 (which sound I really like).
    To make such transducer I've ordered 50 pcs of 85*3*3  N50 neodymium magnets.
    A7zlbyBy_BQ.jpg fYshFYMHSf4.jpg
     
    How I assembled that and what was the result I'll tell later.
     
    GREQ and cskippy like this.
  9. WaffleIron
    Just out of interest, what adhesive did you use to attach the membrane to the acrylic? 
     
  10. Garuspik
    Very good question! I've tried 5-6 glues before I've found perfect variant:
    568617345_w640_h640_90_1.jpg
     
  11. chinsettawong
    Very interesting project.  [​IMG]
     
  12. MrTie84
    Subscribed, very interested in how this comes together for you, very cool.
     
  13. ericj
     
     
    I believe we've seen at least one Fostex T-50 (vintage) variant made of Kapton. 
     
     
     
    Yes, the more pricy vintage Fostex T-50, it's OEM variants, as well as the Sansui SS-100 and similar Akai model, have a bigger driver. 
     
  14. cskippy
    Very interested in progress and results.  Good job man!
     
  15. Garuspik
    Thanks! Let's continue my story. I've made several 40 ohm membranes with 0.25 traces. You can see a result on embroidery frame before glueing.
     
    image.jpg
     
    I've made on cnc router sample enclosure for measurements and listening tests.
    7BUg5BE9oXM.jpg P1013026.jpg
     
    P1013027.jpg Ex_-EtpD-Us.jpg
     
     
    What's the main difference between my designh and hifiman or audeze? Big membrane (82 mm diameter) that is capable to move lot's of air while not travelling far from middle position.
    Look at photos of brand headphones and you understand what I'm talking about:
    1. He-1000. About 4*6 cm active area. It's only 24 sq. cm. Nothing in comparison with huge cup
    HiFiMAN-HE1000-V2-EDITION-X-V2-12.jpg
     
     
    2. Audeze - same story.
    7.png
     
    When I've assembled planar transudecer I've measured it in open space (like tweeter with low pass filter)
    71a03f229590.png
     
    Much better result as you see. Next step is comparison with top brands in local hi-fi store! :wink:
     

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