[2.2 N] Bought them, tried them, loving them. Highly Recommended.

[20 Hz to 20 kHz] I tried HD800 HD600 HD650 K240 600ohms(MIA) K701(MIA) K271.... K712(MIA) is the most serious for Mastering!! I use HD650 to enjoy music(HD800 too fake) , Use K712 to Work. K712(MIA) Really for professional!!

[4.9' / 1.5 m] *Clearly of Midrange
*Ultra Low Distortion in high gain
*Bass is Flat ( OMG!)
*High Quality Cable and Nice mini XLR Connector
*Very Confortable
*Thanks a lot AKG

[Male] SOOOOOOOOOOOOOOOOOOOOO amazing cool cool cool cool

[Open] I listen to classical music and acoustic modern jazzy music (97% instrumental). These headphones sound natural and feel comfortable on my head. If you like the K701 then these are much better. NOTE: They are not bassy; i.e. bass is neutral.

[40 mm speaker] 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.

[2.2 N] I took this one around 1.5 years ago. It is the best headphones that I used ever! Great quality of sound (extremely accurate and detailed sound reproduction), ergonomics, and the great feature to connect or disconnect the cable.

But it's important to say you, AKG. One thing that I don't like it is the lack of a solid case. Make it, please.

[40 mm speaker] 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!

[32 ohms] 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

[20 Hz to 20 kHz] 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.