44 weeks ago I wrote a comfort & quality review on these headphones and said that I would follow-up with my impressions of how they sound...so here goes.
Before I get into the sound impressions I would like to add a few further comments about the fit and comfort. These headphones are very plasticky for sure but that does keep them light weight, a good thing. However the plastic build is VERY susceptible to creaking and squeaking and this IS a big detriment to this headphone. I really don't like how noisy they are. Even the slightest head movement causes squeaking noise. Finally I had enough and decided to check for some lubricant that could be applied to the swivel portion of the cups as well as the adjustment sliders. I found a spray can of Kleen-flo Kleen Slip that we use to apply to our window sliders which is a silicone greaseless lubricant. I wasn't sure if this would affect the plastic or not but decided I couldn't bear all of that annoying squeaking noise. I gently sprayed this silicone onto a cotton cue tip and applied it to all moving parts of this headphone. I'm happy to report that it definitely did reduce the squeaking noise but not entirely. I'll take it for now. Not sure how long it will last though.
Now for my impressions on how they sound.
First off, I like the K7XX's wide soundscape as compared to my Sennheiser HD650, HD6XX, HD58X. What I don't care for is how hard they are to drive. I have 3 amps (Jotunheim, Lake People G109S and Project Ember) all of which are plenty powerful, however this K7XX requires a good turn of the volume knob in order to get them going. Compared to my 300 ohm HD650 & HD6XX and 150 ohm HD58X I need to adjust the volume slightly further with these AKG's. Kind of puzzling because these phones are only 62 ohm.
Sound wise, they have a decent amount of bass but they don't extend too deeply and come across somewhat muted especially compared to the much more satisfying bass on the HD58X. Although similar to the 650/6XX, I prefer the Sennheiser bass. Mids are good but nowhere as good as the HD650 & HD6XX. The treble is where I'm not impressed at all sounding rolled off making them kind of dull sounding.
I don't know if I'm more accustomed to the Sennheiser house sound which has a narrower and more forward (yet intimate) soundscape than the K7XX, I'm having a hard time spending very much time with these AKG's. The Senn's do get knocked for their veiled sound but after I upgraded my amps to the above-mentioned I have no complaints about the Sennheiser treble whatsoever. In comparison this pair of AKG K7XX's are the most veiled sounding headphones in my collection.
The AKG K7XX's have a fairly hefty material like foam covering the drivers that fire toward your ears which leads me to believe that might be the reason why these headphones sound so dull. I need to turn up the volume several clicks further to volume match the K7XX to the much more difficult to drive Sennheisers.
I stopped using them for music listening and use them exclusively for watching TV because they are so comfortable for extended viewing. Incidentally, after extensive searching I finally found an aftermarket knitted headband cover to protect my bald scalp. I contacted AKG to see if they had a headband cover but they never did reply to my request. I wish I could endorse the AKG K7XX but unfortunately they fall well short of my expectations and I am tempted to sell them. Value wise, for what you get for $200 you can do much better.