[11.6 x 9 x 5"] These are just great headphones. I wish they had the detachable cord, like the K702, but overall a spectacular bargain. I don't think they are quite as detailed as the K702, but I find the two close to indistinguishable. I slightly prefer the K612 for computer/television and the K702 for hi-fi, but I've gone back and forth and back and forth. For the price, the K612 is a no-brainer in my estimation.

[62 Ohms] Bought for an open air, expansive sound and wasn't disappointed. One of my most comfortable headphones (out of 12 sets). Love the colorway. I custom made a shorter cable, about 4'.

[Dynamic] I bought these 8 years ago an everytime I put them on I just smile and get all giddy. they sound so amazing. wish real life could sound this good haha but yeah if i had 1 downside id say for the money plastic anywhere isn't cool. but its not like i use them outside. by far best headphones i've ever heard and when playing some games the open back makes pin pointing foot steps in first person shooters almost fell like your cheating. 8 years now an i just put them on smiled again an looked them up to write this review. if you even thinking about them just do it and thank me later

[Stereo] I absolutely love these headphones, they're phenomenal. BUT, for comfort, for your next K series headphone PLEASE make the earpads a little bit thicker while using the same materials. This way people's ears wont touch the driver! That way it would be a perfect headphone!

[Dynamic] I have auditioned a lot of the current TOTL headphones on the market. In that price range, AKG K812 is the headphone to sought after if you want something that is very pure, very revealing, while at the same time very holographic and very musical. Great for both engineers and audiophiles, though some audiophiles will crave for a balanced option.

One small con is that, as it is so revealing, you will not want to listen to your poorly mastered tracks anymore. Also, in some days when you want a soft and mellow sound for your ears, these headphones will sound a bit too sharp and too tizzy.

The reason why I only give 4 stars to the durability is because the screws near the ear cup of the headphone will loosen or tighten on normal use. Though they can be readjusted using a simple screwdriver, this is something not desirable.

[Open-Back] Detailed, engaging sound signature with good spacial imaging. Good base response. The K712s need a good Headphone Amp and DAC to perform at their best. Very comfortable.

[Open-Back] Listening to classical music and opera with the K 712 has become a truly exciting experience reveiling superb dynamic range,definition,transient response and nuances,never heard before with other premium headphones.Highly recommended for music enthusiasts and recording engineers.These headphones also sound excellent on Sony Walkman CD players.

[62 Ohms] When I first started my headphone journey over a dozen years ago, my first serious one was the K702, which I enjoyed foe several years before trying other company’s offerings, both open backed and closed models, and each brought its own pluses and minuses, but as time passed I gravitated to the AKG K712, which was a nice balance of improved, deeper bass and the huge, open and detailed I was craving. I enjoyed the 712 but then moved up to several different flagship headphones which resulted in me selling my K712. Several more years few by and I was still missing the AKG sound but wanted a more refined version. I hit the jackpot when I discovered the K812. I ordered these direct from the company, and after having throughly enjoyed them for more than a week, I feel that I finally found the flagship headphone sound I’ve been looking for. Everything sounds incredible. Classical and jazz really come to life. Vocals are spot on. I’ve also been using them instead of my stereo system for movies, and they really shine. Crystal clear dialogue and huge, crisp reproduction of the movie soundtracks and effects.
These are great all rounders that really deliver the goods. Highly recommended.

[62 Ohms] SOOOOOOOOOOOOOOOOOOOOO amazing cool cool cool cool

[2.15 lb] I had an older version of very much loved AKG reference headphones from the early '90s that were destroyed by my son... after many years of service, many of the plastic elements were held by mini bulldog clamps so good timing for an upgrade, thanks, son!

After listening to a lot of alternatives, many costlier, (although for the listening pleasure I have put cost on a low priority criteria scale) the K712 PRO was the right choice: better sound than my previous ones and still the same neutral yet accurate and true experience for my mostly classical and jazz listening. Paired with a SHIIT Bifrost DAC and Valhalla tube amp stack, every instrument is clearly distinct and spatially identifiable. You feel you are in the space with the musicians, be it in a studio or concert hall.

Also own a Grado PS500e - a warmer experience perhaps that I enjoy with a more "mobile" red Dragonfly DAC/Amp when working, but I find the AKG's neutrality better for the orchestral music I often listen to. And the comfort fit bears no comparison between them: I can wear the AKGs for hours - not so for the Grados

The open back was a must for me as I usually don't like (or need) to feel isolated. In the rare condition I need to withdraw from the surroundings I reluctantly use a Meze 99 classic walnut pair that match the comfort of the AKGs with an enjoyable sound stage but not close in accuracy to my preferred cans.

Minor detail: I replaced the velvet cushions with fabric covered AKG ones. Found the sound stage to be even more detailed.
The only criticism I would have is the elastic threads holding the headband. After a few years they show signs of fatigue and I don't know how easy it is to replace them. Not a big concern as the excellent comfort does not appear to be affected.

Headphone choice is a personal affair. Every ear is different, everyone's sound processing, taste and pleasure seeking is different. The K712 PRO are perfect for me.