For quite some time I was curious as to what was truly out there when it came to good headphones. Being interested in upgrading from my Audio Technica ath-m50 headphones I scoured the web for information on headphones reading numerous reviews and comparisons. The hd600 came up relatively often and was praised for its great value, neutral sound, ability to handle near any genre, and comfort. Seeing it available at $300 down from $400 like new, I convinced myself to go for it.
The wait for it to arrive could not go fast enough and amazingly enough this was the first time I have had a product arrive before the estimated delivery date. Finally it was time to spend some time getting used to my new headphones and sizing them up. What I found was really quite surprising.

The bass was the most obvious difference right off the bat. Coming from the m50's which are supposedly bass heavy and "v shaped" in their sound signature I expected the bass to take a back seat with these headphones. Nearly all comments I have heard on bass about the hd600 described it as light, or neutral, most certainly not the bass-head's headphone. At least for me, the low end sounds very present and well represented. Actually for the first time in some tracks I felt like I could properly hear the previously washed out bass line. If this is what bass neutral sounds like I can only imagine the slam in a bass heavy headphone.

The mid-range is slightly fuller and clearer but I would not say the difference is night and day. As for the treble I notice the least amount of difference. I can say for certain that harsh highs or sibilance are practically non-existent provided the source is not overly so to begin with.

The deciding factor on me choosing an open backed headphone was my desire for a greater sense of space, an effect I so often hear described by reviewers. To my disappointment the hd600 appears to be lacking in this department almost severely. Switching back and forth between my closed pair and these reveals no significant difference in sense of space. I did account for difference in recordings thinking that maybe I am simply not listening to music that demonstrates an impressive soundstage. After listening to some binaural and spacious recordings I have concluded the soundstage is indeed minimal.

With these headphones being open I was concerned about their leaking of sound perhaps to the point of annoying others in the same room. Thankfully it is far less an issue than I anticipated. For an accurate comparison, play your music of choice (a little louder than you would normally listen) on some closed headphones with them off your head and point the cups outward. What you hear will be pretty close to these.

Something odd I discovered is that these headphones actually sound louder than my m50's with the same exact volume level. I have no idea why this is as both the hd600's sensitivity rating and ohm rating are greater than the m50's. I am using these headphones with only my onboard sound on my pc. I was prepared to buy an amplifier to go with them, but I find I get ample volume even with the quietest of tracks. If anyone has any critical comparison experience of these headphones with a stronger amplifier and its effect on the sound I would love to hear about it.

The comfort on these headphones is fairly mediocre. The pads could stand to be much softer and roomier. Unexpanded the headphones are very small, but they expand quite a lot, more than I could ever see someone needing. The clamp is strong out of the box, so much so if you need to move around for some reason while wearing these they will not be going anywhere. The clamp can be lessened by fully extending the bands and bending just the exposed metal. Bending the plastic along with it would probably cause it to break. Speaking of general build quality and aesthetics, these headphones are not bad at all. They do not exude class or luxury like some others in the same price range, but they are well put together and look great in my opinion. The weakest point is the swivel on the cups. They feel loose and not sturdily attached. The cable included is very thin and does not seem to be of very high quality. I like a thin and light cable myself but if you would like an upgrade, the hd650 cable looks much beefier.

I am faced with a dilemma. I do enjoy these headphones, but do I feel they offer $300 worth of improvement, even spread over their lifetime? I would say no. at the full price of $400 I would strongly suggest trying out headphones in person and consider what things are most important to you in a headphone. At this price point, I feel a high end experience can be expected in all aspects of form and function.

In conclusion, the merits of the hd600's are seemingly substantially over exaggerated. This is not to take away from their solid performance, but until these headphones reach a price point of $200-$250 I suspect there are better choices available.

Edit: Due to concerns about me not evaluating the hd600 with proper amplification, please take my comments about sound quality with that in mind.

Edit Part 2: It has been quite awhile but I can now update this review after having purchased an O2 headphone amplifier. My findings are on the unfortunate side, as It seems I can't hear any discernible difference in sound quality using the headphones from my  onboard sound v.s my headphone amplifier. I once again tried using them with my Iphone 4 and compared with the amp, but the results were the same. This goes completely against what I've been told countless times, leading me to believe expectation bias for audio must be incredibly powerful.
For quite some time I was curious as to what was truly out there when it came to good headphones. Being interested in upgrading from my Audio Technica ath-m50 headphones I scoured the web for information on headphones reading numerous reviews and comparisons. The hd600 came up relatively often and was praised for its great value, neutral sound, ability to handle near any genre, and comfort. Seeing it available at $300 down from $400 like new, I convinced myself to go for it. The wait for it to arrive could not go fast enough and amazingly enough this was the first time I have had a product arrive before the estimated delivery date. Finally it was time to spend some time getting used to my new headphones and sizing them up. What I found was really quite surprising. The bass was the most obvious difference right off the bat. Coming from the m50's which are supposedly bass heavy and "v shaped" in their sound signature I expected the bass to take a back seat with these headphones. Nearly all comments I have heard on bass about the hd600 described it as light, or neutral, most certainly not the bass-head's headphone. At least for me, the low end sounds very present and well represented. Actually for the first time in some tracks I felt like I could properly hear the previously washed out bass line. If this is what bass neutral sounds like I can only imagine the slam in a bass heavy headphone. The mid-range is slightly fuller and clearer but I would not say the difference is night and day. As for the treble I notice the least amount of difference. I can say for certain that harsh highs or sibilance are practically non-existent provided the source is not overly so to begin with. The deciding factor on me choosing an open backed headphone was my desire for a greater sense of space, an effect I so often hear described by reviewers. To my disappointment the hd600 appears to be lacking in this department almost severely. Switching back and forth between my closed pair and these reveals no significant difference in sense of space. I did account for difference in recordings thinking that maybe I am simply not listening to music that demonstrates an impressive soundstage. After listening to some binaural and spacious recordings I have concluded the soundstage is indeed minimal. With these headphones being open I was concerned about their leaking of sound perhaps to the point of annoying others in the same room. Thankfully it is far less an issue than I anticipated. For an accurate comparison, play your music of choice (a little louder than you would normally listen) on some closed headphones with them off your head and point the cups outward. What you hear will be pretty close to these. Something odd I discovered is that these headphones actually sound louder than my m50's with the same exact volume level. I have no idea why this is as both the hd600's sensitivity rating and ohm rating are greater than the m50's. I am using these headphones with only my onboard sound on my pc. I was prepared to buy an amplifier to go with them, but I find I get ample volume even with the quietest of tracks. If anyone has any critical comparison experience of these headphones with a stronger amplifier and its effect on the sound I would love to hear about it. The comfort on these headphones is fairly mediocre. The pads could stand to be much softer and roomier. Unexpanded the headphones are very small, but they expand quite a lot, more than I could ever see someone needing. The clamp is strong out of the box, so much so if you need to move around for some reason while wearing these they will not be going anywhere. The clamp can be lessened by fully extending the bands and bending just the exposed metal. Bending the plastic along with it would probably cause it to break. Speaking of general build quality and aesthetics, these headphones are not bad at all. They do not exude class or luxury like some others in the same price range, but they are well put together and look great in my opinion. The weakest point is the swivel on the cups. They feel loose and not sturdily attached. The cable included is very thin and does not seem to be of very high quality. I like a thin and light cable myself but if you would like an upgrade, the hd650 cable looks much beefier. I am faced with a dilemma. I do enjoy these headphones, but do I feel they offer $300 worth of improvement, even spread over their lifetime? I would say no. at the full price of $400 I would strongly suggest trying out headphones in person and consider what things are most important to you in a headphone. At this price point, I feel a high end experience can be expected in all aspects of form and function. In conclusion, the merits of the hd600's are seemingly substantially over exaggerated. This is not to take away from their solid performance, but until these headphones reach a price point of $200-$250 I suspect there are better choices available. Edit: Due to concerns about me not evaluating the hd600 with proper amplification, please take my comments about sound quality with that in mind. Edit Part 2: It has been quite awhile but I can now update this review after having purchased an O2 headphone amplifier. My findings are on the unfortunate side, as It seems I can't hear any discernible difference in sound quality using the headphones from my  onboard sound v. s my headphone amplifier. I once again tried using them with my Iphone 4 and compared with the amp, but the results were the same. This goes completely against what I've been told countless times, leading me to believe expectation bias for audio must be incredibly powerful.