[100VoltTube]

Maybe because they use much thinner diaphragms, they need to stretch them more

 

[chinsettawong]

About the coating material, I know what I use isn't the best, but it does serve the purpose. I fixed a few pairs of Stax headphones by simply coating one of the diaphragms with the new coating, and the headphones come back to sound balance with good bass. So, I don't think it's the coating material. I often check the tightness of the diaphragm by knocking the spacer which has the diaphragm glued on against a table and hear the sound. Stax's sounds much sharper than mine.

Recently, I have been making my diaphragms using the 1.5 micron Mylar, but still I can't achieve the same tightness as Stax. If I do, the bass is much less.

The thing I raise up this question is that there is certainly an advantage in the high tightness as Stax's. As we have often heard of the term "Stax's fart", it actually happens when there is a quick change in pressure within the cup when the headphones are worn on the head. The diaphragm hits one of the stators and bounces back. On mine, the diaphragm would hit the stator and just stick there. I need to unplug the headphones and discharge the bias so that the diaphragm bounces back.

 

[edform]

About the coating material, I know what I use isn't the best, but it does serve the purpose. I fixed a few pairs of Stax headphones by simply coating of one the diaphragms with the new coating, and the headphones come back to sound balance with good bass. So, I don't think it's the coating material. I often check the tightness of the diaphragm by knocking the spacer which has the diaphragm glued on against a table and hear the sound. Stax's sounds much sharper than mine.

Are you sure that you are not being fooled by the fact that your stack is glassfibre board while the Stax stack is metal? I would expect them to sound a lot different when the edge is tapped on a hard surface.

Have you actually tested the resonant frequencies of the respective diaphragms?

Ed Form

 

[chinsettawong]

The stators on Stax SR007 are made of double sided plate through holes PCB same like mine. I don't have the equipment to test the resonant frequencies, unfortunately.

But here is a link where my phones have been tested against the SR009: https://www.innerfidelity.com/content/extraordinary-diy-electrostatic-headphones-chinsettawong

 

[edform]

The stators on Stax SR007 are made of double sided plate through holes PCB same like mine. I don't have the equipment to test the resonant frequencies, unfortunately.

But here is a link where my phones have been tested against the SR009: https://www.innerfidelity.com/content/extraordinary-diy-electrostatic-headphones-chinsettawong

Sorry, I was somehow confused and assumed the comparison was SR009 which, if I remember correctly is the nearest Stax equivalent to you devices - and which, of course has a metal stack construction. Looking back over your original post I see that you clearly said 007, so my fault for making assumptions.

You can measure the self-resonance of the diaphragm by placing a loudspeaker close to it and sweeping it across the frequency range where the resonance lies - a tiny spot of light on the diaphragm will visibly blur when the diaphragm excursion increases around its resonance. Sweep up and down once or twice and you'll easily determine the frequency of maximum movement. If you have the diaphragm on its own and your speaker is small and near the diaphragm, you may even be able to detect a little peak in the impedance of the loudspeaker .

Ed Form

 

[J-Pak]

I did some searching and I couldn't find if Sennheiser ever mentioned what the HE-1 stators are made of. Does it look like they're PCB?

 

[chinsettawong]

Can’t really tell from the picture. But the old Orpheus has gold sputtered on glass as stators. So, I think Sennheiser has a better technic when it comes to making stators.

 

[J-Pak]

Can’t really tell from the picture. But the old Orpheus has gold sputtered on glass as stators. So, I think Sennheiser has a better technic when it comes to making stators.

The reason I was wondering is if they were using glass stators I would have imagined they made this very public, as it was in pretty heavily advertised by them in HE90 promotional/review material.

 

[jgazal]

The Making Of $53K Headphones

(...)

The problem is that glass, which comprises top-end audio electrodes, starts to swing in those outlying frequencies. “It’s the same principle as the resonance created by running a finger around the rim of a wine glass,” he adds. “So we needed a stiffer material.”

Enter zirconium oxide. The ceramic material had been around, but mainly used to repair teeth. A process to sculpt electrodes from this material didn’t exist, and its assets—stiffness and strength—also created the most vexing manufacturing challenges.

Grell’s team needed to puncture an array of 4,650 0.7-mm holes in the electrodes. The electrostatic force created by the electrode and diaphragm (a thin membrane a fraction the width of a human hair), moves the diaphragm and blows the air through the holes creating a sound field with less than 0.01% harmonic distortion. A specially designed diamond-tipped drill broke after a couple of attempts. So they had to reconfigure an injection molding and grinding process to create, then resize, and smooth the holes to a surface with no detectable microscopic grooves. The cost for the measurement machine alone was $270,000.

(...)

 

[chinsettawong]

IMO, the different tensioning of the diaphragm and the diaphragm thicknesses make more difference in sound than the difference in stator designs. But Sennheiser does have its very unique and expensive way of making the stators.

 

[chinsettawong]

During these past few days, I've been having the pleasure of listening to the wonderful Stax SR-Omega.

Before sending them back to the owner, I need to take a picture with my very own Omega.

 

[Garuspik]

chinsettawong ,have you ever experimented with inverted ESL designs with low-resistant membranes?

 

[chinsettawong]

Hi Garuspik,

No, I have not. In fact I have thought about it for quite sometime but haven't got the chance to try it yet. Maybe on one of these days, I will.

 

[Garuspik]

I'd love to see new players in ESL league. And you seems the only person who can brake Stax hegemony

 

[tigon_ridge]

@Chinsesttawong Wooow. I remember frequenting this thread in 2011 when it was still young, and you'd just built your 2nd pair of electrostats--You're still at it! I'm really impressed by your craftsmanship, diligence, and love for the hobby. It seems you're still using mylar. I wonder what kind of material Stax uses. They probably have a lot of tricks up their sleeves. Keep at it, Sir. I haven't read through all the pages, so I'll ask: has anyone gotten a chance to listen to your creations, and given their impressions? Are you still designing and building your own amps to power them?