[mulder01]

   
I've already asked this question on the second page of this thread: You deliberately renounce magnet bars on the back of the membrane in the interest of minimizing reflections just to add such a perforated plate with about 40% sound permeability and 60% reflectivity? I would have preferred magnet bars instead.
 

 
My guess would be, like with the Abyss (and every other headphone?), there will be something between the back of the driver and the back of the earpad that absorbs or redirects the sound coming backward.  I suppose you would start with a completely open backed driver then slowly work out what you can do to to partly close off the back of the driver with a negligible effect on the sound.  
 
If you can get a high end sound out of completely closed headphones, then there must be some pretty good methods of deadening the sound that is heading backward into the earcup.  A couple of little mini anechoic chambers on the back of the drivers perhaps...  I mean, I know nothing about designing headphones, so I'm just guessing, but I'm sure these guys have a fair idea what they're doing and it won't just be: driver - air gap - aluminium housing...
 
As far as I'm aware, the alpha dogs were made by using old drivers out of another headphone and they just improved the reflections and other things around the driver and managed to vastly improve the sound and they are closed back too, so clearly things can be done.  I suppose you can make a non reflective foam more easily than you can make a non reflective magnet structure.

 

[Joe Skubinski]

I should probably make something clear. Diana is not designed to replace our flagship AB-1266, she is being developed to be a different animal. We're even designing a new driver specifically for her, so acoustic needs differ.

Any surface near the planar driver has a dramatic effect on sound. Magnets are most definitely impactful to sound, being positionally fixed as close as possible to the planar film by design, forcing their effect on the sound, whereas the rear of the headphone is something we have complete control over, including it's position, composition, and design/shape.

Also, and I'Il reiterate, what we are currently showing is not necessarily up to date, nor indicative of the final design.

 

[Beolab]

Joe;
Thanks for the nice info, its very intresting to read on your progress in the developing of this ground breaking concept headphone.

Is the name Diana reflecting the sound characteristics in any way, if the Abyss is the man in the household with a more throaty sound with a V shaped curve, then the Diana should be in my mind very fast light sounded with out of the world Stax 009 detailed, with a more ultra controlled bass, or can you tell us what sort of sound you are aming at?

 

[Joe Skubinski]

Diana will be a bit more easy going, smooth, clean, yet not quite as critical of source material as our AB-1266. No worries with bass capabilities.

 

[HiFiGuy528]

Will we get to see and hear the new baby at RMAF?
 
Hey, how can I get AB smiley face??? I want it in my signature! 

 

[Music Alchemist]

Hey, how can I get AB smiley face??? I want it in my signature! 

 
Images like that one don't normally work in signatures. However, emoji does!
 
http://www.head-fi.org/t/765858/check-out-the-cute-icons-in-my-signature
http://www.getemoji.com

 

[JaZZ]

  My guess would be, like with the Abyss (and every other headphone?), there will be something between the back of the driver and the back of the earpad that absorbs or redirects the sound coming backward.  I suppose you would start with a completely open backed driver then slowly work out what you can do to to partly close off the back of the driver with a negligible effect on the sound.  
 
If you can get a high end sound out of completely closed headphones, then there must be some pretty good methods of deadening the sound that is heading backward into the earcup.  A couple of little mini anechoic chambers on the back of the drivers perhaps...  I mean, I know nothing about designing headphones, so I'm just guessing, but I'm sure these guys have a fair idea what they're doing and it won't just be: driver - air gap - aluminium housing...
 
As far as I'm aware, the alpha dogs were made by using old drivers out of another headphone and they just improved the reflections and other things around the driver and managed to vastly improve the sound and they are closed back too, so clearly things can be done.  I suppose you can make a non reflective foam more easily than you can make a non reflective magnet structure.

 
Sounds like a reasonable explanation. On the other hand, there are only a few millimeters at best for damping the rear sound waves before they bounce against the rear grill, so a complete absorption before that is impossible. Yes, there are a lot of closed-back headphones that sound passably good, but there's a reason why they are considered a worse design when it comes to audiophile demands and soundstage/imaging, and I absolutely support this attitude from own experience. Think about it: Even «anechoic chambers» arent' free of reflections – the lower the frequencies, the harder the absorption (that's why the acoustic in them has an unnatural signature, in contrast to a free field). Even less possible is a complete absorption in closed headphones (also in view of the concerned wavelengths) – therefore their reputation for being inferior to open designs when it comes to accuracy and realism. The rear sound waves are mixed to the direct sound.
 

I should probably make something clear. Diana is not designed to replace our flagship AB-1266, she is being developed to be a different animal. We're even designing a new driver specifically for her, so acoustic needs differ.

Any surface near the planar driver has a dramatic effect on sound. Magnets are most definitely impactful to sound, being positionally fixed as close as possible to the planar film by design, forcing their effect on the sound, whereas the rear of the headphone is something we have complete control over, including it's position, composition, and design/shape.

Also, and I'Il reiterate, what we are currently showing is not necessarily up to date, nor indicative of the final design.

 
That's certainly true: the closer, the more impactful. The question is: does this equate to «more harmful»? Or the other way round: Is the distance of a few millimeters really less harmful to the sound than one millimeter or less? The larger the distance, the more likely that you're confronted with reflections  audible as such (given the runtime), not just coloration. Holding my hands on the back of my electrostats or the HE1000 provides a good example of this effect. The housings of said electrostats are homegrown, BTW, and one of the improvements I had in mind compared to the Stax originals was massively reduced reflections from the rear grill. The difference is very obvious. HiFiMan has even patented the HE1000's rear grill design which takes care for the very same issue – and it does it very well to my ears.
 
Moreover I'm convinced that you get reflections from the front magnets as well, actually from the membrane interacting with the magnet's facing surfaces, plus from the space between the magnet bars. But the latter is of course inevitable and can't really be criticized (unless you go the HE1000 route). After all your reasoning about close reflections being most harmful sheds some interesting light on the electrostatic driver principle – which is considered as being perfect, whereas its downsides are often overlooked and overheard.

 
So yes, the few millimeters allow for some damping material between driver and rear grill. But I strongly suspect the reflections from the damping material (!) are audible as well. Not as reflections, but as reduced transparency.

 

[Joe Skubinski]

Sounds like you need to build your own headphones, simply for the experience..

 

[Music Alchemist]

Sounds like you need to build your own headphones, simply for the experience..

 
He did.

 

[Joe Skubinski]

Let's see it!

 

[Music Alchemist]

Let's see it!

 
An image of one is linked in his signature. You'll have to ask him for the details of it and the other.

 

[Joe Skubinski]

Thanks for that. Electrostats are a bit of a different animal.

Our original planar designs, tried it both ways and went the way of a single sided design- took lots of theoretical sh.t. for it too, until they hit the market. We have a patent pending on this design.

We also did extensive work with materials and reflections of the planar wave, learned a lot from that.

FYI, that test hole pattern on an initial prototype you commented on, that cut was not designed to listen to, it was made to test the finish after drilling many holes and what we needed to optimize the machine code for a clean appearance. it's about 60% open as shown, the angle of the pix fools the eye. Current side prototypes are running about 85% open, have yet to be optimized for the diaphragm. We do not use damping in the AB-1266, diaphragm is critically damped, just as with your home-made stats.

 

[JaZZ]

I guess I have concentrated too much on acoustics and forgot the portability aspect. A rear grill such as on the HiFiMan HE1000 probably wouldn't be robust enough for that purpose.
 
Apart from that, I'm not criticizing your magnet array, just the grill which seems to contradict its main goal. Every driver principle has its pros and cons anyway.
 
 

  An image of one is linked in his signature. You'll have to ask him for the details of it and the other.

 
Thanks for the hint! Actually both are linked there. You'll also find some ribbon/planar speaker drivers in the photo collection.

 

[Joe Skubinski]

Will we get to see and hear the new baby at RMAF?

Hey, how can I get AB smiley face??? I want it in my signature! 

We may have a private showing you're of course invited to.
I tried placing an image link to the smiley face in the sig code, doesn't work. Would be cool if head-fi added it to their collection.

 

[Music Alchemist]

I tried placing an image link to the smiley face in the sig code, doesn't work. Would be cool if head-fi added it to their collection.

 
Even if they did, it still wouldn't display in signatures. You have to use characters like emoji. (Shared in this post.)