Beyerdynamic 483966 DT 990 Premium 600 ohm HiFi HeadphonesI own this headphone AND the DT 990 PRO 250OHM headphone. I really think in my opinion these are the best OPEN CAN headphones for the price range. I bought a bunch of other ones in the price range before and ended up very unsatisfied. Example: Philips Audio Fidelio X2HR, Audio-Technica ATH-AD500X , Sennheiser HD 599. None of those were acceptable to me. My ears just really gravitate to BeyerDynamics GT990 series headphones so why not just buy it again ?I bought this one because I wanted to use it for just dedicated music listening on my hifi stereo. I use the 250ohm "pro" for computer usage for mastering multitrack recordings (note not for actual recording since they leak a LOT due to openback design, but for mastering songs).HEre is my main obvservations between these "premium 600ohm" vs "pro 250ohm":1. These are lighter on the head2. These have straight cord rather than coiled3. The obvious GREY vs black open back look4. These are 600ohm , and require a good headphone amp to drive them -- my stereo has a really good discreet headphone amp and they sound amazing -- without an amp, you will find them somewhat quiet. The 250ohm require less power to drive them and actually can be used direct to phones too5. This 600hm version sounds just a TOUCH crisper than the 250ohm version --- if you dont like clinically crisp sound, then you will not like them.6. To be honest, I find for some reason the "airyness" or "open" "wide" sound stage is better on the 250ohm version (?) It 's likely i have not broken them in enough but at first listen, thats my gutt feel. After a good 50hours maybe i'll feel differently.7. This comes with a very nice caseIf you dont know what the DT900 series sound like in general? I will describe them as extremely open and "airy" , very wide 3D sounding headphones. They are not the flattest response but thats not what i want in music listening. It's an exciting musical headphone, very forward treble crispness. Not heavy bass but very well balanced bass and just enough mid end presence to make vocals sound right up there. Comfort-wise, I've yet to ever complain wearing them for an entire 8hour work day!! NEVER gets hot around the head. Never fatiguing because it is very light. Portability isnt the forte since it doesnt really fold. It's too bad the cord isnt replaceable though.I'm really happy with this and i highly recommend giving this a shot if youre around the ballpark of ~250-350 price range and looking for an openback set.