Djeeeezus!
I put on a set of Brainwavz HM5 pleather pads on my HE-6 instead of the Audeze "vegan" pads and WOW!
These pads are really what HE-6 needs to get the bass right! Bass is
considerably much more hard hitting and tight - and dynamics are just frightening. On tracks with lots of sub bass, the bass quality is simply staggering and has that character I expect is usually called layered. This is definetely on par with the best quality bass I have ever heard.
When I had my Audeze LCD-2 v2, the only reason to keep it over HE-6 was it's superb bass quality, but now - with the MH5 pleather pads, I am not sure that would have been the case. I don't have the LCD-2 any more, because the HE-6 trumped the LCD-2 in all other areas both in therms of SQ and comfort, so this is of course based on memory, but still - the bass quality out of HE-6 with the HM5 pleather pads is just so much better now, that I suspect they will play bass on at the same quality level.
I thoght that dynamics of HE-6 was among the best possible out there, but the HM5 pads simply lift it to previously unknown hights. Wow! (I know, I said it again - but it's just wow!)
In short, the HM5 pleathers are keepers and the vegan pads are heading for the trash bin (well not really, but you get my drift).
I have put a piece of felt between the hair screen and the pads (not covering the opening of course), and this adjusts the sligthly higher level of upper treble that I got with the HM5 pleathers compared to the vegan's. Also, since the HM5 pads are oval in shape, I have inserted the mounting ring from the old HiFiMan velour pads to make the HM5's fit the cups.
And the second best part: The HM5 pleathers are just a fraction of the price of the Audeze pads...
Edit: The Brainwavz HM5 pads has memory foam (in addition to high quality pleather), and I expect this is the reason why they perform so well.