[36 Ohms] These headphones are exactly what I was looking for when I purchased them almost 30 days ago. Basically I like everything about them: The sound is perfect for what I do in the studio, that is a sound and video editing very clear and transparent with a lot of detail. I think these are the best headphones I have ever owned. The AKG K812 headphones are very comfortable, well/solid built, and easy to adjust while on your head. I also like very much a stand that comes with these headphones. I purchase the headphones with the AKG HP4E 4-Channel Headphone Amplifier - all works great!

[36 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.

[300 mW] Sounds amazing with Xonar DGX card without EQ. Very fast and natural bass, detailed heights, scene is amazing. The best for long-time listening and gaming, very comfortable.
Cons: not for bass-heads and not-detachable too long cable.

[Open-Back] Bought them, tried them, loving them. Highly Recommended.

[Stereo] I bought these about a month ago and have used them to mix music in my home studio. They are comfortable, lightweight, and the sound is extremely accurate. The flat frequency response is perfect for mixing tracks in a song. I am very pleased with these headphones.

[Open-Back] 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.

[Dynamic] Truly a masterpiece. Extremely good build quality with gorgeous design, I'm glad that the headband system and the entire frame were redesigned from old Denons. Comfort is quite amazing, plush and soft ear-pads, just the right size, perhaps could be a little deeper/tricker but it would impact the sound quality for sure. The headband was a little stiff in the beginning, I was always aware of its presence on my head but it got really comfortable over time the point where I don't even feel it anymore. Also bonus points for a detachable cable!

The drivers are extremely resolving and detailed. They produce very tight and punchy bass like most Denons / Fostex, perhaps here they're slightly more in line with the rest of the spectrum. Highs are polite and never fatiguing at all, definitely not veiled. The midrange sounds very intimate, personal and detailed, slightly forward. The notes have weight to them and feel very realistic. The overall tonality is quite balanced with that extra warmth added to make things enjoyable for long listening sessions. However, the vocals sounded a little too harsh in the beginning but luckily got much smoother after the burn-in period (about 30 hours).

The only gripe I have with it is the stock cable, it's got a strange plastic feeling to it, it's quite microphonic and doesn't want to straighten out even after months. Luckily there are many aftermarket options and I replaced mine with a custom one.

Overall and absolutely stellar product for its asking price so if you loved the older Denon / Fostex sound you should definitely check these out!

[300 mW] 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.

[Stereo] My performance duo purchased 2 of these headphones in Italy last summer. Our sound engineers found them comfortable to wear and musically pleasing. After returning to rhe US we purchased another. Highly recommended!