Mixing on calibrated monitors should always be preferred, but when you do not have that option the NDH 30 is an excellent alternative that translates very well to other systems. They don't sound "nice" at all, but the moment your mix sounds great on them you know it will sound great anywhere, which is exactly what this tool is meant to do. It is also an excellent secondary tool to listen to exact panning of tracks, or to use for difficult editing where the smallest details must be cut inaudibly.
Mechanically it is a fine product, with good fit on at least my head, but the earpads tend to slip a bit towards coming off their shells. I wish they would stay exactly where they are fixed, but their rubber "skirt" tends to work itself a bit out of the rim in which it is holding.
Some people have reported frequency changes with these headphones when moving them back and forth on their head, but I have not found this problem with how my ears are shaped and positioned. The sound is pretty much the same whether I move them back or forth. So, clearly your mileage may vary. You'll probably have to try for this aspect yourself.
I have a lot of other headphones that I can reference these to (also twice the price), but the NDH 30 gives me the best translation of all of them. I do not use any form of playback EQ and I mix and master very finicky classical music most of the time.
