Bests & Worsts Reviews from Amazon

I bought these as well as the Beyerdynamic DT 1990 Pro to compare the two. The latter lost, easily. The HD 660 S is incredible. No frequencies pop out like the Beyerdynamics (too harsh in the high end), everything is very even. Excellent in the mid-range for sure, unlike many headphones that try to push the higher frequencies to come across as "super pro." It's natural for our brains to go "ooh" when we hear bass, or crisp highs, but you don't want these things when judging a mix! Bass is quite good (but not ear-rumbling), about as good as my Shure SRH1540's. If you want a good pair to judge bass and sub-bass, definitely grab the Audio-Technica ATH-M50x in addition to the HD 660 S, and prepare to be amazed—I've never heard such good subs in a pro level headphone. Don't get the ATH-M50x as your sole pair of headphones, they're problematic in the mids and mid-highs. Some things to keep in mind with the HD 660 S: - These are pro level open-back headphones meant for studio use, so you must be in a quiet environment to use them properly. Also, don't wear them in public because external noise will ruin it for you, and you'll annoy people around you because they'll be able to hear everything. - Headphones sound a little better after a brief burn-in period (48-72 hrs). Plug them in, put them on your ears, and fire up some heavy rock or electronica at a volume that's loud, but not painful. Then remove the headphones and let them sit for a few days. This loosens up the material around the drivers. Some people think this is a myth, but some of the best mix engineers in Hollywood disagree. In short: get these headphones, they're incredible!