Model that replaces the pro550, the membrane was changed the response is not at all the same: it is good! the 550 was a failure, that's a good value for money. to the mix is ​​far from being fairly flat course, but to use record, instrument or even a good media is good. level defects, it lacks a little serious, and eventually do some harm to the ears to listen long (it depends also ears ...). I regret a little my AKG K44 that made the soul but he's still has replaced honorably.