In designing its fourth-generation consumer noise-canceling headphones, the QuietComfort 15s, Bose has done something interesting. Instead of coming up with a whole new look for its headphones as it did with the QuietComfort 3s, Bose has left the basic design of its popular QuietComfort 2s intact and simply redesigned them on the inside, adding even more effective noise-canceling circuitry and improving their sound quality.
 

The QuietComfort 15s look identical to the QuietComfort 2s, with the same over-the-ear design, including earcups that swivel and fold flat to fit in a stylish case. (To be clear: the QC15s replace the QC2s, which will no longer be sold.) Bose has redesigned the case so that it's easier to plop the headphones in it and close it up. The resulting package is slightly bigger than a CD wallet, which makes it easier to tote, though it's still not terribly compact. As you'd expect from a set of headphones designed for frequent travelers, Bose throws in a two-prong airline adapter. The 'phones also offer a "high/low" switch, which should prevent your ears getting blasted when the pilot or flight attendant comes over the PA system.
 

As we said about the QuietComfort 2s, even without the noise-canceling engaged, the earcups' deliciously soft cushions effectively sealed off our ears from the noisy environment. While the QuietComfort 2s only had noise-canceling microphones (for detecting the ambient noise) on the inside of the earcups, the QC15s have them on the inside and outside, which is said to increase their effectiveness. Flipping on the noise cancellation--which pumps out "anti-noise" to proactively counteract the environmental sounds--damps down the noise even further.
 

Of course, there's a catch. Like all other noise-canceling headsets we've reviewed, the QuietComfort 15s produce a sense of pressure on the eardrum. Listeners sensitive to this effect may find it anywhere from mildly annoying to distractingly uncomfortable. Most of the former group will tend to forget about it as soon they start playing music or movies. If your experience is more the latter, noise-canceling headphones aren't for you--stick with noise-isolating in-ear headphones instead. (Luckily, Bose offers a 30-day money-back guarantee, so if you don't like the QuietComfort 15s, you can return them.)
 

This reviewer has a very loud air-conditioning system in his office that we use for testing noise-canceling headphones (it isn't quite as loud as the inside of an airline cabin but it's not that far off). The QuietComfort 15s were able to almost completely silence the sound of the rumbling fan. Oddly, the impact of engaging the circuitry may seem a bit weird--it almost feels as if you're at the bottom of a pool, almost completely shut off from the sounds above.
 

As with all of Bose's noise-canceling headphones, you have to engage the noise-canceling to listen to music, and when the battery dies, so does the music. Luckily, battery life is good.

Bose rates it at 35 hours, and the single AAA battery, which resides in the right earcup, was still going strong after we left our tunes in a loop overnight. Those looking for a rechargeable option can either opt for the QuietComfort 3s, or invest in their own third-party battery and charger. On the plus side, sticking with standard alkalines means there's no wall charger or AC cord to worry about when traveling.