[Folex]

If the headphone is open does it matter how close or how far the driver is from the mesh? If it does what sound would you expect with a driver close to the mesh opening vs far away ?
 
ex. Driver close to the mesh opening.
 

 
Driver further back from the mesh opening.
 

 
And also comparing these 2. The HD800 is tight around the sides of the driver whereas the ad900x is completely open. Does that affect the sound @ all ?

 

[castleofargh]

to me it's just a way to keep the back open but at the same time forbid a genius to touch what he shouldn't.
 
you see it as the mesh further away from the driver, but here I tend to see the driver further away from the ear ^_^.

 

[ieee754]

Length of 10kHz sound wave is about 3.3cm, so mesh distance can create dips in extreme highs range if the length is (n + 1/4) * wavelength (n is some natural number), because of the sound wave reflections. So for example if length from driver is 0.5cm then it can nullify 15kHz (depending on how dense is the mesh).

 

[Folex]

  to me it's just a way to keep the back open but at the same time forbid a genius to touch what he shouldn't.
 
you see it as the mesh further away from the driver, but here I tend to see the driver further away from the ear ^_^.

 
The driver away from the ear I've done extensive research and I feel for my hearing I have the perfect distance, pitch and offset. I've never given much thought to how the driver vs mesh distance affects the sound. I'm looking to create custom cups/baffles and I want to put all the best design features into 1 headphone. I had a perfect idea until I saw the hd800 and wondered how much the driver vs mesh distance affected the sound.
 

  Length of 10kHz sound wave is about 3.3cm, so mesh distance can create dips in extreme highs range if the length is (n + 1/4) * wavelength (n is some natural number), because of the sound wave reflections. So for example if length from driver is 0.5cm then it can nullify 15kHz (depending on how dense is the mesh).

 
So strictly from a driver to mesh distance comparison the ad900x is superior to the hd800 ?

 

[ieee754]

 
So strictly from a driver to mesh distance comparison the ad900x is superior to the hd800 ?

I think that this means that in theory HD800 is better because if there is any dip, it falls into inaudible frequency range. But you would need to do a lot of measurements to objectively say which one is superior (and of course that depends on your definition of "superior").

 

[Roly1650]

I think that this means that in theory HD800 is better because if there is any dip, it falls into inaudible frequency range. But you would need to do a lot of measurements to objectively say which one is superior (and of course that depends on your definition of "superior").

Really dumb question, but isn't the mesh the wrong side of the driver to have any audible effect anyway, unless the ear pads don't seal properly? I would think the mesh is designed to be audibly transparent, it is after all there to keep foreign objects out of the back of the driver. There are as many different configurations of the exterior screens and screen distances as there are headphone manufacturers, anybody is guessing to know one is better than another, some drivers may well benefit from a partial air loading on them, others maybe not. Like you say, it would require a whole heap of measurements to find out and the results may well be surprising or pointless.

 

[MrTechAgent]

Expect the difference to be minuscule.
What matters is baffle retention to membrane...to ensure optimal excursion.