I get these as a sad gift - the overall sound quality be quite bad -lrb- when nc - noise cancellaton-is turn off -rrb- . not much low frequency and minimal high frequency content . so purely as headphone - they fall at the bottom of the heap . with nc turn on , there be some amplification of the sound - so it sound louder . the nc effect itself - well - its kind of work , but not much . probably about 20 percent of the noise be take care of . do not even try compare the performance of the bose to these -lrb- I do so - use a co-passenger bose qc3 - and it be a revelation - one work beautifully and this one barely do so -rrb- . I plan to get a pair of Panasonic RPHC300 now -lrb- since I do not have $ 300 to burn -rrb- . I be curious how the nc effect be implement for the left and right earpiece . there be no wire that connect the right side -lrb- with the battery and nc electronics -rrb- with the left earpiece . go figure this one out : -rrb- . I have some idea - but that would mean this be not a stereo headset . too lazy to experiment further with this piece of junk . the good thing be they fold quite well .