No one can deny that the original Beats by Dr. Dre was a revolutionary headphone design. It brought style and pizazz to the headphone market, and turned on a new generation of music lovers to the joys of great sound. The Beats Studio ($350) is still selling like gangbusters, but the Beats line has expanded to include something better, the Beats Pro ($450).

The Studio Beats have a lot of bass, but the Pros have more and distinctly tighter, more visceral bass. The two headphones sound very different; the Pros have a brighter, more forward balance, and the Studio Beats sound relatively laid back. Oh, one other thing, the Studio Beats are battery-powered noise-isolating headphones; the Pro is not, so it doesn't use batteries.

The Pro's build quality is miles ahead of the plastic Beats; the Pro's metal headband and metal earcup holders feel nice and solid. This headphone should stand up to a lot more punishment than the standard Beats, or most audiophile-grade headphones for that matter. The Pros feel like they could last 10 years. The thickly padded ear cushions and headband convey a feeling of luxury, but comfort was only good, not great. These headphones put a fair amount of pressure against your ears, which can get tiresome after a few hours of use. Being a sealed headphone design it blocks outside sounds and noise. The Pro is available in black or white finishes.

The Beats Pro folds for compact storage and comes with a soft carry case. The detachable 1.8-meter Monster headphone cable is coiled at the plug end and the coil extends the cable's length to 2.1 meters. The thick cable has a 3.5mm plug, and you get a beautifully finished, all-metal 6.3 mm adapter plug. The Beat Pro is an extremely efficient design, so it can play really loud with an iPod.

The solidity of the bass was the main thing I noticed as I switched back and forth between the Beats Studio and Beats Pro, but they sound very different overall. I think the Pro will have more audiophile appeal, but that's not to say it sounds like the open-back designs from Grado and Sennheiser. Those two let more sound from your environment through, but the Pro sounds more "canned" than any of the open-back Grados or Sennheisers I've heard. That open quality may (or may not) be something more audiophile oriented listeners crave. The Pro's bass punch totally creams similarly priced Grados and Sennheisers.

On Wilco's "Wilco (The Album)" the Pro sounded spacious and airy; Jeff Tweedy's vocals were clearer and more present on the Pros. The Studio Beats shelved the mix down a notch or two, so everything sounded more vague and diffuse. While rocking out with the White Stripes' "Under Great White Northern Lights" CD, Meg White's drums kicked harder over the Pros, and definition was absolutely superior. And when I played Miles Davis' "Bitches Brew," the Studio Beats clouded over the recording studio's atmosphere; the Pro is the more transparent-sounding headphone.

B & W's P5 headphone looked a little dainty next to the brawny Pro, but the sound of the two headphones on Los Lobos' "Live at the Fillmore" CD was an interesting study in contrasts. This is a very bass-heavy recording, and the P5's low-end gusto was nicely developed, but the Pro further clarified the bass drum's pounding beats. The Pro revealed more of the live recording's "liveliness." The Pro's hard hitting dynamics kicked harder than the P5's, and the Pro just plain sounded better cranked way up loud. The P5 was the winner with acoustic music; the Pro's overly abundant bass was simply too rich (for me), and the treble was too aggressive. Those qualities worked better on electric music.

The Beats Pro sound may not be to everyone's taste, but what is?