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My DIY electrostatic headphones - Page 39

post #571 of 1690

The thickness of the stator and the size of the holes are crucial parts of the design and they are tied together.   

post #572 of 1690

 

Found that, but postage to the UK is £30 :(

post #573 of 1690
Quote:
Originally Posted by Nixon View Post

 

Found that, but postage to the UK is £30 :(

I thought that the seller I pointed out to offered free shipping but it isn't the case. So if you find a cheap enough source for the printed circuit board, let us know

post #574 of 1690
Thread Starter 
Quote:
Originally Posted by Nixon View Post

 

Found that, but postage to the UK is £30 :(

Yea.  Unfortunately, the postage is quite expensive.

post #575 of 1690
Thread Starter 
Quote:
Originally Posted by bidoux View Post

Could these work too ? (shipping is really expensive with amt33461 )

http://www.ebay.com/itm/360377165165?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648 and http://www.ebay.com/itm/360377165921?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

 

And as for the stators, how important is their thickness ? I thought that it wouldn't matter as much as with the spacers.

 

I always use 1 mm PCB for stators and 0.5 mm PCB for spacers.  Since Stax also uses the same, you can't go wrong with those.

post #576 of 1690
Quote:
Originally Posted by chinsettawong View Post

 

I always use 1 mm PCB for stators and 0.5 mm PCB for spacers.  Since Stax also uses the same, you can't go wrong with those.

 

What model has 1mm stators? All the pictures of electrostatic headphone products I've seen appear to have nearly paper thin stainless steel stators.

post #577 of 1690
Thread Starter 
Quote:
Originally Posted by dude_500 View Post

What model has 1mm stators? All the pictures of electrostatic headphone products I've seen appear to have nearly paper thin stainless steel stators.

How many have you seen? Try to look into those of SR007 MK1 and MK2.
post #578 of 1690
Quote:
Originally Posted by chinsettawong View Post


How many have you seen? Try to look into those of SR007 MK1 and MK2.

 

I always imagined the SR007 driver to be very thin. The picture looks like it has tiny holes, and you would never want the hole diameter to approach the thickness or resonances could form within the stator holes.

 

 

Anyways, on my progression of building headphones I've completed my first pair that are effectively done. Of course, I'm already building my next pair! I've concluded large and rectangular simply isn't the way.  Since I now have access to a laser and router, I have SR007 earpads on the way and will be making headphones quite similar to chinsettawong's omega clones. If anyone wouldn't mind sending me the dimensions and mounting system for the SR007 earpads so I don't have to wait a week to start the CAD process, I would greatly appreciate it!

 

 

Here are some pics of the headphones I recently finished (bulky, extremely heavy, and a bit ugly... not exactly the direction I had hoped they'd go from the beginning, but I learned a huge number of things to do and not to do):

 

 

 

 

Most important lesson in these was that earpads are everything. Change the material, the method of covering the foam, just about anything and the sound changes completely. Hence why I chose to go with a pre-manufactured earpad.

post #579 of 1690
Thread Starter 

Hi Dude_500,

 

Your headphones look really nice and well made. How do you make the plastic enclosures?

 

About your comment on the hole size should not approach the thickness of the stator or the resonance could form within the stator holes, is there an article about this that you could point me to?

 

Do you suggest that the hole size should be larger or smaller than the thickness of the stator?

 

Wachara C.

post #580 of 1690
Quote:
Originally Posted by chinsettawong View Post

Hi Dude_500,

 

Your headphones look really nice and well made. How do you make the plastic enclosures?

 

About your comment on the hole size should not approach the thickness of the stator or the resonance could form within the stator holes, is there an article about this that you could point me to?

 

Do you suggest that the hole size should be larger or smaller than the thickness of the stator?

 

Wachara C.

 

The main enclosure is all laser cut 0.25in ABS. Spacers in this build are not FR4. Instead I used 0.02in styrene sheet so that I can laser cut it. Works just as well, I put a strip of copper foil tape on one side to contact the diaphragm.


I was suggesting the holes be larger than the thickness, but I may be imagining all of this. I can't find a reference. Perhaps my memory became distorted and I was recalling that the hole spacing must be much smaller than the smallest wavelength.

post #581 of 1690
I believe it's not so much about the resonance in the holes (nowhere near te audio range) but the damping. The small DS gap and perforations contribute to the damping of the diaphragm because of thin layer viscous effects. I believe some comment was made on the headwize reference.

By the way, Dude 500, I started to make a VA One model of your geometry, the old one that was causing a resonance. Trying to see if I can reproduce the problem with a simplified model. Utterly useless for you at this stage, it's mostly learning experience for me wink.gif.
post #582 of 1690
Quote:
Originally Posted by arnaud View Post

I believe it's not so much about the resonance in the holes (nowhere near te audio range) but the damping. The small DS gap and perforations contribute to the damping of the diaphragm because of thin layer viscous effects. I believe some comment was made on the headwize reference.
By the way, Dude 500, I started to make a VA One model of your geometry, the old one that was causing a resonance. Trying to see if I can reproduce the problem with a simplified model. Utterly useless for you at this stage, it's mostly learning experience for me wink.gif.

 

It ended up being more an issue of the material than the geometry. Memory foam of softness "very soft" causes terrible resonance, be it raw foam, or foam covered in leather. Polyurethane foam of softness 25% deflection @ 1PSI is great either raw or covered with leather. Polyurethane foam of softness 25% deflection @ 0.3PSI is great as raw foam, but has very bad resonances when covered with leather or velvet.

 

All tests were very repeatable, and although obviously I couldn't test every possible geometry, it seemed to be a material issue rather than geometry (of course, the geometry will set what the resonances are... but my point is same geometry with varying materials had these varying effects on the intensity of the resonance).

 

 

If anyone knows even the diameter of the circle that the SR-007 earpad mounts to, it would be much appreciated!


Edited by dude_500 - 9/24/12 at 10:24am
post #583 of 1690
Thread Starter 
The outer circle of the cup is 110 mm. If you need other measurements, let me know.

Wachara C.
post #584 of 1690
Quote:
Originally Posted by chinsettawong View Post

The outer circle of the cup is 110 mm. If you need other measurements, let me know.
Wachara C.

 

Only other thing is how it mounts, pictures look like it's just a friction fit slide onto the cup. Is this the case? Or if it's some elaborate mounting mechanism that's difficult to describe, just let me know and I can patiently wait for my pads to arrive to analyze.

post #585 of 1690
Thread Starter 

For Stax 007, the sleeve on the pad simply goes into a small opening on the side of the cup.  As for my design, I use the same mounting mechanism as HE-5.  It's rather difficult to explain.  I can take a few photos to show if you want to.

 

Wachara C.

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