I bought these to compliment my Beyer DT770's which I've always enjoyed the sound of, even if they don't have the most balanced sound signature compared to my other "reference" headphones, such as the Sennheiser HD600 or Roland RH-A30. I find them to be very capable in their own right and even I'd say the balance between the bass, mids and treble is very tasteful and workable for most material.

So the idea of an open back DT770 with some additional treble sounded great to me. Unfortunately my impressions, both at first and after some weeks, have been the same; they sound like how people will exaggerate the DT770's sound signature. You have extremely high amounts of bass and forward treble, but the mids are left alone. They make my DT770's sound like Sennheiser's in comparison.

It's not that I'm against the V sound signature—I used Sony headphones for years! But the DT990 has been coloured to such an extent that certain instruments will sound wrong. I have a few tests, such as tracking specific sounds and listening to certain kinds of music, where these fail completely; distorted electric guitars that have very forward, aggressive mids will sound like they're mid-scooped like it's the 1980's heavy metal scene all over again. There are certain genres that this headphone just cannot reproduce with accuracy.

Beyer claimed that these headphones are for mixing, but I don't even think I could use these for any sort of tracking with how extreme they colour the sound signature.

For positives, it's built wonderfully and I've had no worries in terms of how long they will last. They're also extremely comfortable, just as expected as a DT770 owner and I really like the way they look.

And while the sound signature is not to my taste at all, they do sound very detailed with no blurring or noticable gaps in the frequency range. I even enjoy the treble these have. I just wish they had more forward mid range, which has made me realize that I already have that... the DT770. I ended up selling them because of that.

In terms of preference, I'd actually say that these headphones hit a sound signature that I personally really did enjoy for listening to music. They have quite a relaxed, airy sound that isn't lacking in details either and they made certain genres of music really shine, namely jazz, country and orchestral. Less so for rock and electronic music, but still a decent sound.

The issues I fell into was mainly about that mid-bass boost that gives specific instruments a resonsant, boxy sound that can cause you to make bad decisions when tracking and editing. A snare drum that sounds balanced on these could end up sounding hollow and distant on any other sound source. For that reason I couldn't keep using them because I had to constantly compensate and work around that issue. It also means it tends to over-inflate music that already sounds quite compressed, like pop and metal.

They remind me of the sound you can get when you have decent monitor speakers set up in a less-than-ideal room; you still having an over-all pleasing sound... just keep in mind the room is messing up that low end.

I spent a long while with these headphones but was never able to click with them before moving on. They are built very nicely, appear to be quite reliable and are one of the most comfortable headphones that I've used.

I'd generally describe the sound as relatively consistent as you have no drastic sudden peaks or dips, which makes it quite easy to leave a neutral impression and to also get used to their sound signature. They make music sound fine and by all accounts they're a decent pair of headphones.

The issue I have is that while the sound signature is consistent, it is skewed towards clamping down on the mids and having treble that, while can be quite smooth, lacks detail. Again, there's no obvious bad aspects of this headphone to me once you're used to it, but it can be quite a night-and-day difference when you switch to a headphone such as the HD600, K371 or DT990 and realize how much aggression and forwardness is not present in the X2HR.

The combination of a recessed mid-range combined with a lack of detailed treble veils instruments which gives an artificial sound-stage. It all culminates in a headphone that gives the impression of a neutral sound but doesn't perform as I would hope for anything more than general music listening.

I bought these as they were recommended to me as a neutral closed back headphone that I could use while monitoring and as a back-up for reference. The version that I recieved was the latest MKIII revision with the detachable cable.

I'm not a fan of the over-the-top packaging that AKG provides but the headphones themselves are definitely built well and a lot less stressful to handle than AKG's own K371, which has noticable points of potential failure. I wouldn't be surprised if the AKG K550's last for a long while if they're treated reasonably well.

My initial issues with this headphones is that it has poor clamping and doesn't grip to your head very well, instead it mainly just presses on your ears. Any sort of movement or adjustment can change the bass response quite drastically. There's a few rough DIY tricks such as bending the metal headband to make them fit tighter, but I found that it doesn't really help the situation and just ruins the support and comfort you get from the headband.

In positive terms, I'd describe the sound as bright and forward with good enough detail in the upper mids and treble, with a lean but smooth low bass that isn't bloated. For real world use they are good at catching clicks, sibilance and for tuning harsh frequencies in productions, and would probably work nicely as a monitor style headphone.

In negative terms, and the reason why I did not stick with them, is that I can only describe the upper bass and lower mids as scooped. Instruments with a lot of low-mid energy such as guitars, acoustic basses, pianos, snare drums and cellos sound brittle and thin; snare drums and pianos lack weight, an orchestra sounds distanced and hollow, balanced guitar tones sound scooped like it's the 1980's again. It was just difficult to enjoy them because they did not represent what I knew was actually happening.