The AthM50s are fantastic set of closed headphones! I have not owned any other so good headphones.
The Ath-M50 S bass is really great. The bass extension is actually incredible and there is lots of influence, sounds wonderful. The AthM50s highs are extraordinary, and also the mids are good, although recessed. This V shaped sound signature in fine for more contemporary styles of music.
Overall, ATH-M50s have an excellent sound. They keep away a surprising level of outside noise and do not leak in any way. Really Comfortable. My only complaint is the fact that they are created out of all plastic, however the plastic appears very durable and strong so that is not actually a problem. Wonderful headphone, especially for this price tag!