The Dekoni ferenstrated lambskin pads also helps address the the treble region peak that the SDR & my Senn "S"mod foam addresses.
The drawback is slightly less bass.
I believe this is a design choice that Dekoni made on that pad base.
The plastic base does not have the "membrane" on bottom that stock pads have to retain bass..
Yet the other Dekoni pad choices were not as "open" sounding.
This is very important to me.
My approach is not using anything that is less open sounding than stock.
That is why in this thread, there is no selection or mention of ANYTHING that would reduce soundstage.
So no use of internal rug liners, or creatology foams, or really anything that would decrease the effective
internal volume.
This is also why I am switching to Dekoni ferenstrated lambskin pads, regardless of bass issues...
Stock pads reduce internal volume as they are already shallow, and get more shallow as they get old...
It is my opinion that the HD800 driver design benifits from more internal volume.
My studying of it leads me to believe that the larger volume better propagates the soundfield wave pattern, like what a horn speaker does.
Also any room speaker does similar, by projecting outward the image, and as it disperse, it fills the room getting larger..
I feel the planars & electrostatics have the advantage of a way more flat sound wave pattern to travel to the ear, but the wave is already "large", so the ear is already immersed in a large sound wave, and the ear's localization cues detect a large image.
So, my opinion is that the HD800 basket frame helps the driver simulate a larger spaced image.