I didn't use my HFI 580 anymore so I thought I'd play with it some. I always found the highs to be too prominent and piercing.
I didn't really understand the bass monster reputation these cans have, since I'm already deafened by the treble when I turn up the volume to try to hear any significant bass impact.
So I opened them up to see if I could improve the sound some.
This is how they look stock (note the DJ1 marking on the solder terminal):
Then I proceded to apply some dynamat extreme to the inside of the cup, the magnet, and baffle:
In order to smooth out the treble, I applied some cotton wool to the dynamat on the cups. The edition 9 also seems to have this damping in their cups so I thought it could only improve the sound:
Whoa what a different beast!
Not only is the treble way more smooth and more in balance with the rest of the spectrum, the whole sound has stepped up a league. The sound is way more controlled and refined. Mids are more forward, vocals are now way more intimate, lifelike and without sibilance, awesome! Detail seems to have increased due to the faster decay. They lost that artificial metallic sound and have more natural timbre.
I highly recommend this mod. Just be careful, since the cables are very delicate. I wouldn't attempt this if you can't handle a soldering iron, in case you mess it up.
Edited by Aizura - 7/1/14 at 8:06am