In our tests, the first thing we noticed about the P5s is that they aren't overly aggressive and lean to the warmer side, with dynamic, well-balanced sound, full bass, and good clarity.
Steve Guttenberg, who reviews home theater speakers and high-end headphones for CNET, liked how the P5s sounded, too. However, he noted that the P5s, when he listened to Peter Gabriel's "Scratch My Back" album, had a more "upfront/closer perspective" than his mellow-sounding (and now discontinued) Sennheiser HD 580 headphones, which have an open-back design. "Some of that difference can be attributed to the P5s' brighter tonal balance," Guttenberg said, "and Gabriel's vocals and the orchestra's low strings seemed more immediate over the P5s." He also noted that the P5s are clearly the better headphones on rock (their bass is more powerful and dynamically alive than the HD 580's bass). Treble is very present--not too bright or soft.
Guttenberg, like a lot of audiophiles, prefers headphones with an "open-back" design because the music sounds less stuck inside your head and more airy. However, open-back headphones leak sound and don't do a good job of shutting out external noise.
This reviewer spent some time comparing the P5s with the Bose QuietComfort 3s, which retail for $50 more, have a similar on-ear design, and are targeted at a customer that B&W would presumably like to tap into: business travelers who don't mind paying $300 for headphones.
In terms of comfort, we gave the nod to the Bose headphones, but the B&W's feel better made overall (read: sturdier). The P5s delivered slightly more clarity and tighter, punchier bass. We notice, however, that the P5s needed more volume to drive them, which also held true when we put the P5s up against the Monster Beats by Dr Dre Studio headphones. Editor Justin Yu has a pair and had this to say: "I preferred the Monsters for pop, hip-hop, and other genres that rely on electronic instruments, thumping bass, and heavy mixing. But the B&Ws sound better with jazz and more 'natural'-sounding tunes."
In the end, we came away liking these B&W headphones a lot. They offer very good sound and comfort, and a tight seal that blocks out a lot of external sound and prevent sound from leaking out. The inclusion of an in-line mic and volume control is a nice bonus for iPhone users and we found the P5s excellent for having phone conversations. Callers said they could hear us fine and we could hear them quite well because the headphones, as noted, do a good job of muffling external sounds.
Aside from their somewhat hefty $300 price tag, the B&W P5s' biggest drawback quite simply is that while they're more compact than bigger over-the-ear headphones like the Monster Beats--and don't make you look quite as goofy wearing them around the streets--these guys really do heat up your ears. That may be a good thing in winter in colder spots of the world, but on warmer days, they're going to get pretty uncomfortable pretty quickly. If you can live with that--and plan on using them more indoors than outside--we have no problem recommending them.
Freelancer Steve Guttenberg and Associate Editor Justin Yu contributed to this review.