Sennheiser's $150 PXC250 noise-canceling headphones are among the best of the breed. Although this model uses an over-the-ear design, its ear cups are the most compact we've seen. Still, the soft, leatherlike cushions seal out ambient noise while the padded headband provides long-term comfort. First-rate sound quality rounds out the equation with extended bass and detailed midrange.
The 250s' ability to provide a hushed quiet over a broad spectrum of frequencies--bass to midrange--was equaled by only that of the twice-as-expensive Bose QuietComfort 2. Its noise-quashing powers are evident on planes, trains, and noisy city streets. We did note that turning on the noise-canceling function added a small amount of hiss, but it was inaudible in the busier environments where the feature would likely be activated.
The noise-canceling circuitry and a pair of AAA batteries are housed in a separate tube, which, at 5.5 inches, is a bit cumbersome to deal with (the only real downside here), but at least it sports a sturdy belt clip. To save space while traveling, the headphone folds up into a tiny bundle. A two-pronged adapter for in-flight movies and a two-year warranty are included.
Admittedly, the sound wasn't as rich as it was with the Bose, but we preferred the 250s' more present midrange and treble frequencies, although this is very much an issue of personal taste. Hooked up to an 15GB iPod, the 250s produced higher-resolution sound on jazz, rock, and classical music. A session with the new Led Zeppelin DVD also left us impressed--and not just by Jimmy Page's killer fretwork; the 250s treated the high-quality audio signal with respect.
One caveat: The PXC250, like many other noise-canceling headphones, produces a slight sense of pressure on the eardrums. Listeners sensitive to this effect may find it mildly uncomfortable.