My DIY electrostatic headphones

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  1. chinsettawong
    Here they are:

    Before:

    [​IMG]

    After:

    [​IMG]

    The new one on the left and the old one on the right.

    [​IMG]
     
    purk likes this.
  2. ts8051

    Hello,
    I followed this method with resonable results. Please do you know how must tension the length for each dimension in % percentage of total length ?

    Theologos Sarafidis
     
  3. chinsettawong
    It’s very difficult to say just how much tension is enough. As for what I’m making right now, I only aim for about just a little less than 1 mm elongation.

    You can also try to tension it a little more than needed, and then use a hot air gun to treat the diaphragm afterward.
     
  4. ts8051
    Hello,
    please let me know the glass area dimensions on which you tension the membrane, just in order to calculate the percentage of tension. As I mentioned I followed this method with a 25 x 25 cm glass area and with 1mm elongation. Now the resonance frequency is 130Hz and the lowest frequency reproduced 38Hz. If I use a bigger glass area, for 1mm elongation the tension will be lower (the half), thus I wait further improvement.
     
  5. chinsettawong
    I now only use the inner tire method for tensioning the diaphragm. The inside dimension of the frame is 23 x 15 cm.

    [​IMG]

    [​IMG]

    I normally make a few pairs with little different tensions, and test to see which ones I like best. Very sorry that I don't have the exact number of the elongation figure as it's very difficult to repeat the process exactly every time.
     
  6. ts8051
    Hello,
    If you follow the method you described, and in an x attempt the tension is the best with best result in fidelity, how can you measure the result in order to repeat the tension in the future ? We must find a measurement method. Possibly if we can achieve the lowest tension for the best frequency responce in low frequencies, we can apply the air pressure in order to just disappear the ripples in membrane only. In that case the sequence can be repeated in the future, if this lowest tension is the best.

    Theologos Sarafidis
     
  7. ts8051
    Hello,
    Please, if you know from your expiriments, if we apply tension on a membrane and the use the heat gun for each channel with a regulated temperature (for instance 400 degrees centigrade) is the tension the same ? Also is it lower or higher ?

    Theologos Sarafidis
     
  8. chinsettawong
    Hi ts8051,
    The question about diaphragm tension has been raised up again and again, and my answer is still the same. It's very difficult to find just the right tension. Since I do the headphones for my own use, I normally make a few pairs with different tensions and see which ones I like better. It's rather difficult for me to describe just how difficult it is to repeat the same tension everytime. You have to try it by yourself to know what I mean.

    Using a hot air gun to treat the diaphragm will actually reduce the tension. So, you can make the diaphragm with a little more tension then treat it with the hot air gun to reduce the tension a bit.
     
  9. ts8051
    Hello,
    Please, explain how the dust cover can transform the frequency response. Please also do you know the material of dust cover.

    Theologos Sarafidis
     
  10. ts8051
    Hello,
    From the math above i can say that for a given tension T the resonant frequency f can be lower if the mass M of membrane is higher. So if we have a 6micron membrane the bass response is better than with 2micron membrane. Then i cannot understand why stax uses 1.5micron membrane ? Is it something wrong with math above ?

    Theologos Sarafidis
     
  11. ts8051
    Hello,
    I used the heat gun (150 degrees centigrade) and the tension was increased as the resonance frequency increased from 100Hz to 200Hz. The membrane is 3micron.

    Theologos Sarafidis
     
  12. ts8051
    10_Oct_2017_23_50_59.jpg
     
  13. ts8051
    Hello,
    In my new headphones i tensioned the membrane with elongation 0.25mm (the membrane surface is 35 x 35 cm. The result is the following by means of my android mobile phone running Advanced FFT program (the upper yellow curve is the frequency response):
    10_Oct_2017_23_50_59.jpg
     
  14. Muamp
    Hi ts8051,

    With a frequency response that GOOD, I would say your tension must be spot on..... But as always, the listening test is the best test.

    David.
     
  15. ts8051
    Hello,
    As I made many spacers, with my CNC, with a tensioned membraned glued i discovered that even i use scale and 0.5mm elongation the results are varying. Many have simple good response and one until now has excellent with deep bass.
    I thought that when we tension the membrane we must be able to measure the frequency response before apply glue. For this I study to use a bicycle wheel and with inflate for membrane tension. Then I thought that I can apply at first the conductive material (licron crystal spray) and then assemble the headphone without screws but with strong magnets 10 x 2mm which i was already ordered. Then i will test the frequency respone of this temporary assembled headphone and if it will not good i will apply more tension until i have the best results.
    What is your opinion ?

    Theologos
     

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