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My DIY electrostatic headphones - Page 121

post #1801 of 1812

Been lurking at this thread from the beginning almost. :-)

 

Want to thank Chinsetta and Tachikoma, and others contributing to this thread.

 

Have a pair of 404's that in one side didn't sing much.
The driver has been re-coated. And now sings again :-)

As Tachikoma has recommended quite a few times I wasn't shy applying the  coating. Used a micro fiber cloth to rub/polish the mylar as I didn't have a proper sponge.

 

No squeling, buzzing and I could play rather loud until the 212 sort of gave in.
I use some tape with mild adhesive to cleanup the stators before assembling. Seems to work fine.

 

I will glue the driver today and the it takes about 24 hours to harden up.
So I guess I'll have the final result in a few days.

 

The most tricky part of this seems to be cracking the driver open without messing up. I use a rather big Stanley knif with fresh blade, and a lot of patients ... but it does take a while to crack it open as for my experience.

 

Thanks again for all the contribution

post #1802 of 1812

For those who are still interested in measurements and quantification, here is a simulation made with the simulator developed by Arend-Jan on his web site :

 

http://quadesl.nl/sim/

 

 

Don't worry about the yellow line : it is not meaningful.

 

You can see that for 500V of polarization and 750 V peak to peak of the modulation, the levels reached for the whole audio band are quite impressive, around 108 dB !...

 

OndesX


Edited by ondesx - 3/28/15 at 7:35am
post #1803 of 1812
Quote:
Originally Posted by soren_brix View Post
 

I use a rather big Stanley knif with fresh blade, and a lot of patients ...

Hannibal, is that you? ;)

post #1804 of 1812
Quote:
Originally Posted by AManAnd88Keys View Post
 

Hannibal, is that you? ;)

...that would include a nice bottle of Chianti, Clarice!  ;)

post #1805 of 1812
Quote:
Originally Posted by ondesx View Post
 

For those who are still interested in measurements and quantification, here is a simulation made with the simulator developed by Arend-Jan on his web site :

 

http://quadesl.nl/sim/

 

 

Don't worry about the yellow line : it is not meaningful.

 

You can see that for 500V of polarization and 750 V peak to peak of the modulation, the levels reached for the whole audio band are quite impressive, around 108 dB !...

 

OndesX

 

[quote="http://quadesl.nl/sim/"]Like any simulator you can make it do thinks that can not be done in real life.[/quote] ... I guess this simulation doesn't really apply for nearfield, actually you need to be far field for the Walker-equation to be valid AFAIK.

 

Anyways, I really appreciate your postings/efforts in trying to make the stretching process repeatable. Thanks for the effort/contribution.

post #1806 of 1812
Quote:

Originally Posted by soren_brix View Post

 

 I guess this simulation doesn't really apply for nearfield, actually you need to be far field for the Walker-equation to be valid AFAIK.

 

Anyways, I really appreciate your postings/efforts in trying to make the stretching process repeatable. Thanks for the effort/contribution.

 

You're probably right, but anyway I guess it'll give an idea of how it'll work and delivers some numbers !

 

Thank you for your kind words.

 

OndesX


Edited by ondesx - 3/28/15 at 1:18pm
post #1807 of 1812
I had posted numerical simulations in this thread I believe, trying to explain what dude500 observed with various pads depth / size.

Conclusion for me was that you have to think of it as a system. For instance, the free air resonance of driver has nothing to do with the coupled resonance once it is acoustically loaded by the eadpad cavity.

As such, ear pad depth, the amount of leakage through the pads and/or pad-baffle gap all matter. That's why I referred to stax phones earlier in case your design ressembles their dimensions: for omega series, a free air resonance in 120-150hz range translates into a coupled resonance in 40-60hz region which sounds about right target.
post #1808 of 1812

That's why I missed some bass (under 60-80 hz) on my right ear when I used to have middle ear ventilation :o

 

Ali

post #1809 of 1812
Quote:
Originally Posted by soren_brix View Post
 

Been lurking at this thread from the beginning almost. :-)

 

Want to thank Chinsetta and Tachikoma, and others contributing to this thread.

 

Have a pair of 404's that in one side didn't sing much.
The driver has been re-coated. And now sings again :-)

As Tachikoma has recommended quite a few times I wasn't shy applying the  coating. Used a micro fiber cloth to rub/polish the mylar as I didn't have a proper sponge.

 

No squeling, buzzing and I could play rather loud until the 212 sort of gave in.
I use some tape with mild adhesive to cleanup the stators before assembling. Seems to work fine.

 

I will glue the driver today and the it takes about 24 hours to harden up.
So I guess I'll have the final result in a few days.

 

The most tricky part of this seems to be cracking the driver open without messing up. I use a rather big Stanley knif with fresh blade, and a lot of patients ... but it does take a while to crack it open as for my experience.

 

Thanks again for all the contribution

The glueing went a bit wrong.
The stators ended up being a tiny bit misaligned - not much, but enough for the eye to witness the displacement when holding up the driver and looking through the driver. When the stators are correctly aligned it is rather hard to tell if there are one or two stators, even if looking at an angle.
The displacement resultet in an imbalance.

Dismantled the driver again. Cleaned all glue off the drivers and asssembeled the driver, now being hold together by some strong tape.

The two drivers apparantly have about the same volume again.


Still no squeling/buzzing or other strange noises :-)

I guess I need a simple jig to keep the stators in place while glueing.

post #1810 of 1812
Thread Starter 

Hmm.  A little misalignment shouldn't affect the sound level, IMO.  

 

Perhaps you should use a clamp or two to hold to whole thing together tightly when you glue it.

post #1811 of 1812

Or two wood squares with a serious weight on the upper one, the whole thing on a plane surface, this will do the job perfectly !...

post #1812 of 1812
Quote:
Originally Posted by chinsettawong View Post
 

Hmm.  A little misalignment shouldn't affect the sound level, IMO.  

 

Perhaps you should use a clamp or two to hold to whole thing together tightly when you glue it.

 

Quote:
Originally Posted by ondesx View Post
 

Or two wood squares with a serious weight on the upper one, the whole thing on a plane surface, this will do the job perfectly !...

 

Actually did clamp it between two pieces of MDF covered with melamin ... but for some reason it ended up a bit misaligned.

Having the stators eyeball aligned the driver is as loud as the other one again ;o)

But thnx anyways ;o)

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