"They sound okay, but the noise canceling doesn't work."1.5 starson by bporopat
Pros: Not made in China
Cons: Noise canceling is ineffective, low sound level
Summary: The sound quality on these earbud-type headphones is quite good, except that even with the sound up all the way on both an MP3 player and the headphones themselves, the volume is too low. I have excellent hearing, by the way. I tested them by playing various background sounds on an electronic keyboard while switching the noise canceling on and off. My first impression was that they weren't working at all, but on closer listening I could hear changes in sound at different frequencies. I had the same experience testing them with other continuous loud noise sources. At no time did I perceive these changes as being a reduction in noise.
The changes in sound were consistent with phase canceling, which is how noise canceling headphones are supposed to work. To be effective, however, the headphones need to shift the noise exactly 180 degrees out-of-phase to the sound reaching the eardrum, and match the amplitude as closely as possible to the noise reaching the eardrum externally. I suspect this is where the MDR-NC11 headphones fall down. Certain frequencies actually seemed louder rather than attenuated.
When all is said and done, what you have is a nice but insufficiently loud pair of $70 earbuds. Sony makes pretty good passive earbuds for much less. If someone gives you the MDR-NC11s as a gift and you don't have the receipt, use them without the battery, since the noise canceling doesn't work anyway. Don't buy them!