I got some K601 pads in today. They're flat and a little different than Q701 pads. Q701 pads seem harder.
On the Q701 they do seem to make the upper mids and treble a little smoother or reduced a little.
There is a lot less bass and warmth though. No doubt. Not sure how on earth I got less warmth with less treble/upper mids.
I was listening to some tracks and they're really bad on the Q701 with K601 and K400 pads.
One is a crappy recording I found from The Fray called "Syndicate". I would like to hear that on a ruler flat set of studio monitors. On the Q701 with K400/K601 pads it's like listening to a headphone with no bass. Basically thin and tinny sounding.
The Q701 pads add a little warmth and some bass. Sounds OK then. I just wouldn't be able to know how it's really supposed to sound. That track sounded different on all my headphones!
That song is really smooth on the K400 EP, but sounds totally without bass. Sort of like hearing it on an AD700 with rolled off treble
It's interesting that you can't really hear how muffled that track really is on the Q701. I only heard it on the HD-598, HD-650 and DJ100.
I've weeded out all my harsh tracks and theres even some that can be fatiguing even on my HD-650!
TL;DR:
K601 pads on Q701
Smoother treble and upper mids
Less bass/warmth
Smaller soundstage
What the heck?
Low mids less forward
Don't really like at all...