Design and features:The headphones work with or without the noise-canceling feature turned on. You can use the noise-canceling feature without listening to music, and the audio cable is detachable when it's being used only for noise reduction. The headphones have medium-high sensitivity when the noise-cancellation feature is turned on, so they can provide satisfying volume levels when used even with lower-powered portable audio devices. When the noise-cancellation feature is turned off, the headphones have medium sensitivity, so they should work fine with all but the lowest-powered portable audio devices. The QuietComfort 25 has an inline volume control that works with iPads and some iPod and iPhone models, plus an integrated microphone and player function controls that are compatible with iPads, some iPods, and some iPhones and some other cellphones. The call connect/disconnect button can be used with some iPhones and some other cellphones. These headphones may not operate properly with some non-Apple/non-Android mobile devices or other audio equipment. This model has earcups that fold and swivel for travel or storage, and comes with an attenuating mini-plug-to-airplane-jack adapter and a carrying case.
Sound quality: We found the QuietComfort 25 provides excellent active noise reduction and with the noise cancellation feature turned on it delivers sound quality that falls in the excellent range; while no headphone is perfect, the shortcomings of this model are minor. In noise cancelling mode the overall sound can best be summarized as generally smooth but slightly bassy. Bass (as in bass drums, bass guitars, stand-up bass, etc.) has good impact and goes deep, but is slightly prominent and boomy. The midrange (voices, guitars, horns, etc.) is fairly even and smooth, but slightly soft with a hint of an edge in the upper midrange. The treble (cymbals, the upper range of violins, etc.) is fairly extended, but is somewhat subdued and the upper treble is muted. While the sound has a good sense of liveliness it is slightly closed-in -- sound-wise it is a bit noticeable that you have something covering up your ears. The sound is similar sound to the Bose Quiet Comfort 35 noise cancelling Bluetooth wireless model when it is used with the noise cancelling feature turned on, but the Quiet Comfort 25's bass is a touch more prominent and boomy, the midrange is a touch warmer and softer, the treble is somewhat subdued, and the overall sound is somewhat closed in and slightly full. With the noise canceling feature turned off the sound drops to good; the overall sound is muffled and the midrange has a noticeable plastic resonance (something like what you would hear if you talked into a semi-rigid plastic cup). These headphone provide excellent noise reduction overall and is similar to the Quiet Comfort 35. When the noise is coming from the front noise reduction is fairly even across the entire frequency range, when the noise comes from the sides or rear the low frequencies are reduced somewhat more than the high frequencies. When the noise canceling feature is turned on there is a very faint hiss that can be heard in quiet environments when there is no audio program material to mask it; in some situations some users might feel like their ears are a little stuffed up, and if these headphones are connected to AC powered audio equipment there may be an increase in background hiss.
Comfort: We found that these headphones produce a light sense of pressure around ears. As typical of over-ear models the ear pads might feel hot and/or sticky after prolonged use. When wearing this model while walking the vibrations from each foot step can be heard through the headphones.
