At first glance, the QC 15 doesn't look very different than the QC 2—and there's no real explanation as to why the model number jumped so significantly. The familiar black circumaural (around-the-ear) headphone design with silver ear cups has been emulated by several competitors, and Bose stays true to its iconic look with this pair. As always, the headphones fold flat to save space; they fit into a redesigned, but very similar, sturdy black carrying case. Inside the case: an airplane adapter, a long detachable audio cable, and one AAA battery (there's no rechargeable cell like with the QC 3). A switch on the right ear cup activates the noise-cancellation circuitry, which needs to be on to hear audio. Since the cable is removable, however, you can use them to simply block noise, and there won't be a cable dangling awkwardly from your head. Bose estimates battery life at around 35 hours, but your actual mileage will depend on your usage level and the battery you use.

By far the greatest thing about the QC 15 is its improved noise cancellation. While the QC 2 and QC 3 both offer significant noise attenuation, the Creative Aurvana X-Fi—our previous Editors' Choice in this category—and the Sennheiser PXC 450 NoiseGard both rival Bose's noise-cancellation performance. By adding a second microphone—now there's a mic inside and outside of each ear cup—and by using more advanced materials in the padded seal around the ear, Bose has managed to significantly improve upon its previous technology, lowering noise levels in both higher and lower frequency ranges. Who knows whether it's the extra mic or the ear cups' seal passively reducing noise that's the real game-changer here, but the results are undeniable. Not only is the overall ambient rumble of a train or an airplane engine significantly decreased, but there's no audible high-frequency hiss, like you'll get with some other noise-canceling headphone pairs. In an A-to-B comparison with the QC 3 and the Aurvana X-Fi in a loud room, there was no question; the QC 15 prevailed. The noise-cancellation circuitry is the best you'll find, and that's reason enough to buy the QC 15.

Adding to the allure, however, is improved audio performance over previous QC models, although the QC 15 is not for audiophiles. Noise-canceling headphones rarely deliver flat response, and this pair is no exception. While its frequency response offers better bass response than the QC 2, the pair can be overly bright—at times bringing more clarity to an orchestral recording like Jonny Greenwood's score for There Will Be Blood, but at others adding too much sibilance and punch to vocals and piano hits in pop songs, like Grizzly Bear's Two Weeks. Despite the improved bass response, there's still some distortion at high-to-maximum volumes—the deep bass of The Knife's Silent Shout made the QC 15 rattle when listening levels were pumped up in my tests. Normally this would be a significant knock, but at safe-to-moderately-high listening levels, there's no distortion whatsoever; the bass is full and articulate. And the noise cancellation is so excellent that the QC 15 can afford to be strong-but-not-perfect in the audio department.

If audio quality is your first priority, skip the QC 15 and check out Creative's $300 Aurvana X-Fi, which can deliver audio when in passive mode (that is, when the noise cancellation is not activated and the battery is not being used). The Aurvana X-Fi has no distortion issues, and definitely handles the high frequency range with less exaggeration and a little more grace. That said, I suspect most people looking for noise-canceling headphones want to block out the rumble of a 737's engine or the endless drone of a subway car. In this regard, the QC15 can't be beat. That it also offers high quality, if not astounding, audio performance is a bonus. And let's not forget one other important factor for travelers seeking refuge from noise on long trips: True to its name, the Bose QuietComfort 15 is incredibly comfortable.

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