My DIY electrostatic headphones - Page 34
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Edit: Holy schinkes, I'm a page behind. Those are beautiful Amarok. Intense.
Sweat screen from an AT-707. To my understanding these are similar to AT-705, PWB electrets, SR30/40/50/etc. and I'm sure others.
Front grill of AT-707
The Sony ECR-500 and Stax SR-5 have sweat screens protected by a plastic mesh, but no fabric that I remember seeing. The more acoustically invisible the protective mesh is the more it will allow dust and dirt in hence the dust covers you see on the 707's, I'd assume.
Edited by khbaur330162 - 8/25/12 at 8:51am
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To give some perspective on that picture khbaur posted above here are Stax SR-40 and SR-50 electret drivers ( same driver as AT shown above ) that do not have the silver crinkled moisture guard in place.
There is a transparent dustguard on these a thin transparent rubbery thing under enough tension it is hard to notice( can't see it in the pictures at all ) just above where the stator dips down on the driver side of that spacer ring. I measured the spacer ring seen just after the housing lip there and it seems to be no more than 1 mm thick. So the silver thing there is instead of one of these transparent things possibly or on the very top of one if you compare pictures.
Hope that shows some distances and roughly how the Stax/Audio Technica electrets are constructed. The diameter is ~57mm so how that moisture guard spacing varies with bigger driver size who knows.
Edited by nick n - 8/26/12 at 1:52am
Cool photos Congo!
While skimming the old ECR-500 Impressions thread I re-stumbled over this post of ericj's. Gives meaning to the wire mesh outside the ECR-500 stators.
No idea if any of this interests you guys, but it seems like it could be incorporated into your designs. For planar magnetic drivers, use flux plates whenever possible. Could the same be said for electrostatic drivers and electrostatic shielding? I've never heard of an electrostatic loudspeaker manufacturer using this technique, although I admit I'm not that informed.
Edited by khbaur330162 - 8/28/12 at 2:29am
Purrin was so kind to help me make a FR measurements on my Omega clone headphones that I sent to Frank Cooter.
The sweat protection on this one is damping the lower bass somewhat.
P.S. I think the roll off isn't that bad. It's only about -5 dB from 50hZ.
Edited by chinsettawong - 8/28/12 at 11:50pm
Here's something to compare to:
First one is CSD (different time and amplitude scale than the one above!), second is burst decay, third is distortion in % (more like distortion of my crappy microphone ) And the last one is frequency response of left and right channel with new earpads.
And a last thing (interesting maybe only for arnaud), I decided to use just calculator instead ANSYS due to "time deficiency".
My calculator results are: peaks at 4.8 + 2.4kHz, dips at following frequencies: 13.1kHz, 2.7kHz, 6.5kHz, 10.6kHz and 1.7kHz.
Except the 2.4kHz and 1.7kHz all frequencies are correct and I think that's nice result.