Contrarians by nature and innovators to their core, the Roots are always zigging while the rest of hip-hop zags. Best-selling rappers toast their good looks and their Bentleys; the Roots worry in rhyme about drugs, crime and poverty. The standard concert gear for MCs has always been a turntable (or two) and a microphone; the Roots have always been a band, and the sort of band that nimbly darts over the lines that separate rap from every other genre.

The aversion to formats and formulas has won Philly's best-known rap collective a couple of Grammys, steady critical huzzahs and sales just strong enough to keep them in the VIP section of the underground rap world. And they never seem too cunning about any of it. The Roots built this niche -- the socially conscious hip-hop artists, with instruments -- and they luxuriate in it. On a few occasions, they have stumbled, which is the sign of a group assured enough to find the outermost edge of whatever direction they are heading.

"The Tipping Point," the band's seventh album, doesn't lack for nerve, but that doesn't necessarily make it good -- or even particularly interesting. "Point" is the most conventional rap album the Roots have ever made, which is to say that the bandness of this act -- the sense of it as a living thing, in a room, playing -- is hardly in evidence here.

That's no accident. "Tipping" was created in two parts. First, the musicians in the band -- drummer ?uestlove (Ahmir Thompson), bassist Hub (Leon Hubbard) and keyboardist Kamal (Jimmy Gray) -- jammed for a few weeks in a studio. Second, the band sifted for the best grooves, splicing the material into verse-length pieces. Those pieces were then looped together into three- and four-minute tunes and lead vocalist Black Thought (Tariq Trotter) rapped over the results.

The Roots get points for boldness -- they are attempting to bridge whatever is left of the gap between canned rap music and live rock ambiance -- but they get those points at a price. The music on much of "Tipping" is inert, and on tracks such as "I Don't Care" and "Somebody's Gotta Do It" it feels generic.

That puts the burden of "Tipping" squarely on the shoulders of Black Thought. This really is his album, the musical equivalent of a movie in which he is featured in every scene, and he delivers a fierce and tirelessly thought-provoking performance. He's occasionally funny (in a riff about street cred on "Star," the opener, he invokes the name of the highly unthreatening "American Idol" winner, Ruben Studdard) and he can be boastful ("The rebel and a renegade out on a quest / the Super Black Man runnin' with an S on his chest" on "Duck Down!"). Shots are taken at the Bush administration and the war in Iraq, followed closely by lamentations about black-on-black crime. The chorus of the first single, "Don't Say Nuthin'," sounds like the mumbled orders of a drugged-up mugger in the middle of a robbery.

But Thought is a player in an ensemble cast in which the rest of the ensemble barely registers. It's a job that overwhelms, particularly given the seriousness of so much of the material here. You realize what's missing when you reach a pair of hidden cuts planted after a stretch of silence at the end of the last track. One is "The Mic," a scrappy, gloriously unhinged cut with cameos by comedian Dave Chappelle and rapper Ol' Dirty Bastard. Then ?uestlove does a version of an old B-boy favorite, "Din Daa Daa," turning it into a five-minute drum jam. It makes you appreciate what "The Tipping Point" is: a middling production with a butt-kicking afterparty.

The Roots will appear July 30 at Nissan Pavilion.

On "The Tipping Point," the Roots get points for boldness, but those points come at the price of an album that sounds inert.