I've had a couple hours of listening with the NAD HP50 now. For initial listening I had CDs, bluray player, eastern electric DAC, and an Audio by Van Alstine fet valve ultra preamp (using headphone output).
I assume they'll get a little better after more break in, but overall I can't imagine anything better for $150.
I'd say that in general they have a warm sound and wouldn't really classify them as neutral, but this makes them easy to listen to. It's been a long time since I was able to just relax and enjoy the music.
Bass and low notes seem balanced, and aren't overbearing like some other headphones I've experienced. Only criticism of the bass is that on some music it's a little punchy, which I'd describe as a thump sound.
Midbass seems slightly exaggerated and gives an overall warm sound.
Mids seem fairly accurate, but slightly overshadowed by the midbass
I can hear all the details of the highs, and honestly I heard some things I've never heard on my salks before. While all the high sounds are present, they are a little rolled off. For something that I plan to use in my office for hours at a time, I think this is a positive thing that will result in less fatigue.
Soundstage is fairly big, and it's easy to place all the vocals and instruments. Ray Charles - Genius Loves Company was a lot of fun to listen to. The music just had a big sound and the instruments were distinguishable.
I thought I was hearing some sort of distortion, but it's possible it's the "Roomfeel" technology. It could also be the tubes in my preamp. I plan to do some experimenting to figure this out. Not really a negative or major issue, just thought I might have heard a little reverberation or break up on some songs.
The headphones are very comfortable.
Another interesting thing was the tube / solid state button on my DAC. With the push of a button, you can switch between tube and solid state. With various speakers in the past, it was very difficult to hear much of a difference. With the headphones, it was fairly dramatic.
Overall very happy with the headphones. Not neutral and I wouldn't recommend them for critical listening, but I think they'd be great for anyone wanting quality sound that's easy to listen to. I'm still somewhat shocked at the sound considering the pricepoint. I'm very interested in seeing what some of the more exotic headphones have to offer now
At the office now. 160GB Ipod with lossless files, Nuforce Icon Ido DAC/Amp and the NAD HP50.
Sound isn't quite as warm as it was at home and is a little more forward. Bass isn't quite as present either. Still very pleasant to listen to though.
The sound is balanced at low volumes.
I've found that placement around the ears can make a huge difference. If the pads don't form much of a seal, the sound becomes thin sounding.
Isolation isn't nearly as good as the IEMs I was using. In an office environment, and have coworkers who really enjoy talking loudly, crunching ice, and smacking while eating :p