I read and hear the hype of noise-cancelling headphone and how they will make my life much better . so , i go out and bought\/researched most of the top selling headphone . the Aiwa model -lrb- hp-cn5 -rrb- be the most value price . but , it have a buzz when you turn on the noise-cancellation , and i certainly think that most of the noise-cancellation be be achieve by increase the volume than anything else . also , the battery slot be awkwardly place above the left earpiece , and it thus constantly budge against my head . the Sony mdr-nc11 's be quite uncomfortable , and cost nearly 3 time as much as the Aiwa model . the manual say that the noise-cancellation will work only if the earbud be fitting `` snugly , '' and from my experience it seem that the snugly fit of the earbud be what cancel more noise than the noise cancellation technology . I must say , however , that these be the most stylish , sleek and portable headphone of the lot . sadly , they noise cancellation be nominal , and not worth it for the pain of `` snugly '' fitting earbud for extended period of time .  the third model i try be the Sony mdr-nc20 , which be the most expensive of the lot . it be definitely more comfortable than the previous model , and also have passive noise cancellation due to the closed loop cushion design around the ear . however , it will get uncomfortable when wear for long duration due to the small earcup design .  in Summary , all three of these headphone cancel noise by add a `` buzz '' sound when noise-cancellation be turn on , and by increase the volume of the music if plug to a CD player . I would suggest use you money on a better cd player , and get comfortable headphone without the noise cancellation feature . let I suggest Koss UR-20 or Koss UR-30 for beautiful sound quality and comfort , and the Koss the-plug or Sony Fontopia for ear bud type model . all cost less than 50 buck !  enjoy , and i 'll head to the store to make all the return ! : -lrb-