In case folks are finding the AKG QJ 701 on sale and are looking for this kind of input, here's what I posted earlier this year on Amazon:
Recommended, particularly at recent pricing that's below introductory pricing.
I was first attracted to these because of two great names: AKG for headphones and Quincy Jones for producing marvelous-sounding recordings. I didn't always follow QJ's tastes in music genre, but always admired the sound he achieved on disc.
But I didn't buy for fear that there wouldn't be enough distinction between the Q701 and my other fine headphones: Grado RS-1 (open ear pad style) and NAD Viso HP50 (sealed).
Now a friend recently asked me: Why would you need more than one fine headphone? Isn't one better than another, and therefore one best? I gave a nerdy answer but should have answered: a wine connoisseur can answer "Which Chardonnay from 1997 do you find best?" but can't answer "Which wine do you find best?" Different wine varietals are supposed to have different taste profiles, and much of the fun in the hobby is finding a good fit among factors like the flavor of the wine, the mood of the occasion, and the budget. So with headphones.
Thanks to Tyll Hertsens and his InnerFidelity.com site, I chose to buy. Tyll's measurements suggested that the Q701 would be quite distinctive from the NAD and closer, but not the same as, the RS-1. Delightfully, this is the case because the Q701 is distinctive and excellent.
Specifically, the Q701 sound profile tends towards the highly resolving and analytical, exposing lots of detail in the sound. Very "dense" passages from orchestral symphonies or art rock by "Yes" reveal the thread lines of the individual instruments that are contributing to the whole.
The treble and upper midrange are responsible for this sensation of resolution, and the Q701 is definitely "brighter" than the NAD. Have no fear of hiss, sibilance or blare however. The brightness is under control.
The bass is very smooth and nicely extended downwards, going for accuracy and tight bass rather than bombast. Feels right for Classical and acoustic Jazz, but not necessarily as much "fun" for brisk walks in the cool of the evening with Tom Petty in your ears. (Responds well to a slight up-tick on the equalizer at 64Hz.)
Speaking of walks, the Q701 have a higher impedance (62 ohm) than either the Grado or NAD (32 ohm), and so my iPhone 5s does not drive them to more than a "pleasing" volume - loud enough to hear everything fine (with no outside noise), probably good for my hearing health overall, but not loud enough to satisfy my "rock out" or "flood me with symphonic sound" moods. Whereas, powered by my Schiit Asgard 2 headphone amp on my desk, there's more than enough power to satisfy my emotional needs and to bring out all the precision I could ask for in quieter passages. Being open headphones, there's little noise isolation and you'll bother those close by (like your one true love trying to sleep beside your night-owl self).
Ergonomically, the Q701 is a B+, not as impressive as the sound. The best part ergonomically is pulling them down upon your head. The parallel arcs allow the headband on top to slip smoothly into an optimal position, and the ear cups are so large that finding a good place to rest is simple. Less wonderful is the plastic feel of the headband, which so far is stiff. And the ear cups become hot faster than the Grado foam. Reviewers have complained about the "bumps" and I agree that they're noticeable, but any discomfort is more from the material's stiffness than the "bump" design. I'm expecting/hoping that time and wear will remove some of the stiffness from the headband and allow for longer sessions in comfort. (Update after 6 months: as I hoped, more comfy on the headband now, and ear cups softened/molded nicely also.) I wear glasses during most of my listening (if you see me with them off, please - don't speak to me). The foam of the ear cups accommodates my glasses reasonably well. The NAD "molds" itself around glasses for a better seal, which is more important for its sealed design. The Grados are all about open air in any case.
AKG packs two different high-quality cords for the Q701, but neither is "iPod" length. I picked up a shorter cable (1.2 meter) by a third-party manufacturer and it colors the sound a bit (towards bass "bloat") but, as mentioned, it turns out the Q701 won't be my "walkabout" phones anyway.
If you're choosing between the Q701 and the NAD, which are roughly similar in price, the choice based on sound is easy if you know which kind of sound profile you'll (usually) prefer: Q701 for a sense of precision and more "air" in the treble, the NAD for more heart-pound from the bass (while still being an audiophile-accurate headphone). If compatibility with a tablet, smartphone or iPad is key, the NAD is a better choice for loudness and a mic/3-button cable being included. The Grado RS-1 is more than double their pricing and was worth it for me by getting closer to "having it all" in precision, treble air and bass oomph (and the design "cool" factor of wood ear cups). Since I can afford to keep all 3, I am happy to do so. I have a "usage occasion" for each one and expect to have a lot of audiophile "connoisseur" fun "sipping" from each of these wonderful varietals.
