I purchase these headphone when I be write my senior thesis in college to block out all distraction . the sound quality be great , and the noise cancelation be quite impressive . this be the only pair of noise-canceling headphone I have ever use , so I do not have anything to compare they to , but they seem to do a great job cut down on ambient noise . no complaint there . however , after about 4 month of steady use , the speaker in the left ear stop work . if I fiddle with the wire a little bit the sound would come in and out , suggest that a wire have come loose from the speaker . from read other review , this appear to be a common problem , and until Sony address the issue , I would stay away from these headphone . I suppose you sacrifice some durability for the small size , which be too bad . it be important for I to note that I be a incredibly loyal Sony customer , but can not endorse a product that can not stand up to under a year of normal use .