Nice writeup, ampair. I wish more comparisons used this table format. I'd be inclined to say that the K550 is even more "bang for the buck" as they have about 90% the soundstage (which is truly impressive for closed design) and about 85% the detail of the Q701. And the K550 doesn't need a beefy amp to truly shine unlike the Q701.
I'd say overall the Q701 may have overall better sq, but not leaps over the K550. The Q701 is much grainier compared to the totally black background of the K550. It is also subjective depending on your musical taste. The Q701/K702 tend to sound somewhat thin, and for at least some genres, can sound oddly artificial (ie not as musical as K550). Genres like pop and newer rock sound much better on the K550 IMO, but genres like electronic music and jazz/classical sound really good on the Q701, where you may want a more analytical and spacious sound signature. The Q701 does sound very good when it comes to stringed instruments.
I've never used the Audinst hud, but if it's comparable to the FiiO E10 it probably won't be enough power for the Q701. They use a ridiculous amount of juice. If you're looking for a budget amp, I do know that the FiiO E09K actually drives them quite well, and can be had for a little more than $100.
If you can, try them both and sell whichever one you like least. They are both great for different situations.
Also the coloration of both are different; the 550's bass is more prominent, the q701 might be a tad on the lean side, the 550 tad on the warm side, both fairly neutral. Two quite similar (AKG) yet dissimilar sound. I could see some prefering the 550; those who prefer bass bit on the warm side, they do feel more 'powerful'.
Thanks for your detailed views (no pun intended).
I certainly do not want to hear bass slam. would like nice textured bass with good decay.
would prefer a neutral presentation but forward mids is ok. also good performance on string instruments is preferred.
I have not heard a clinical headphone before but I guess musicality is important.
Also i think audinst will drive k550 but perhaps i can create a rig around q701. so both are equal in this regard, i guess.
Also will be buying from another country on a short trip so can't listen and choose. am sure will like em both but a little bit maybe can make a difference.
am getting a bit confused.
Thanks in advance.
Edited by vaibhavp - 12/17/13 at 8:51pm