Leonard Hubbard won't be in the house when the Settlement Music School honors him and 41 other musical luminaries at a Center City gala on Saturday.

Not that Hubbard, who plays bass for the Philadelphia hip-hop band the Roots, doesn't feel humbled to be named one of the Settlement 100 that the Philadelphia school is honoring in anticipation of its 2008 centenary. (The event is sold out.)

Who wouldn't want to be on a list that includes Albert Einstein (who played in a weekly chamber-music group while living in Princeton) and Frank Rizzo (who took clarinet lessons as a child), not to mention blues-rapper G. Love, actor Kevin Bacon and opera singer Wilhelmenia Fernandez?

It's just that Hubbard will be working instead of being feted at the Loews Hotel, playing with what he calls, in a matter-of-fact statement that admits no argument, "the premier hip-hop live band in the world."

As usual.

If it's Saturday, the Roots must be in Perth, Australia. But they could just as easily be at the Tower Theater in Upper Darby, where Hubbard was recently heard doing what he does a couple of hundred nights a year: chewing on his trademark licorice root, and locking in with his drumming cohort Ahmir "?uestlove" Thompson for an unrelenting, musically varied 21/2-hour show.

During which the West Philadelphia native got one extended segment alone on stage, which he used to scat sing and mix graceful melody lines with thumb-picked room-quaking rhythms before bringing the crowd to its feet with the bass line from Queen's "Another One Bites the Dust."

With that, Roots MC Tariq "Black Thought" Trotter reemerged and egged on the crowd with the command "Let's hear it for the bassman!" Hubbard then laid down the groove for "Act Too (The Love of My Life)," in which the rapper proclaims his undying devotion to hip-hop.

Hubbard plays hip-hop for a living. But his musical experience reaches far beyond rap, as he's quick to point out during an interview in the classroom where he studied music theory in the 1970s at Settlement's Seventh and Christian branch.

"I play bass in a hip-hop band," he says. "But my talent is far more diverse than that. I have this whole classical, jazz fusion and composition background." Hubbard, who grew up in the neighborhood around 53d and Girard, began playing bass in fourth grade. Soon, he began studying classical piano as well.

Hubbard got an early education from his older brother Robert's record collection, with Jimi Hendrix and John Coltrane records alphabetically filed in the basement.

Hubbard remembers that another Settlement 100 honoree, bass player Michael Cruse, "had a band called Projection 101, and he lived right around the corner. They played a block party and he had a fretless bass, so I went home and pulled all the frets out of my cheap Japanese bass with pliers," Hubbard recalls. "It was a neighborhood full of musicians. Every Saturday, people would be outside with the congas and drums on the front stoops."

The aspiring musician, who won't give his age but cops to being in his 40s, was in a music magnet program at Overbrook High School. He also studied after school at Settlement, taking private lessons with theory teacher Donald Rappaport. "It was the place where I got my training," Hubbard says, "where I got bass lessons from Eligio Rossi," who also taught jazz bassist Stanley Clarke.

Hubbard studied classical music at Carnegie Mellon University in Pittsburgh and played in jazz, Latin, funk and R & B bands. In 1992, he filled in at a gig at Old City Coffee by a band then known as the Square Roots.

"They didn't know me from Adam," he recalls. "Ahmir told me to take a solo, and when he saw that I was a virtuoso, he was like 'Oh, man, keep playing, keep playing.' "

Since then, Hubbard - who lives in Old City and Germantown when in town - has played on every Roots album, from 1993's Organix to last year's Game Theory. He's one of four core members of the ensemble, with Trotter, Thompson and keyboard player Kamal Grey.

Hubbard has traveled the globe. This year, the Roots will rep the 215 in Beijing and Shanghai. The band, which recently brought the house down with U2's "Pride (In the Name of Love)" at an NAACP tribute to Bono ("Everybody was like, 'Oh, wow, they can play that [stuff], too?") has backed up Bobby Womack and B.B. King, Eminem and Jay-Z.

Rather than play marathon shows, Hubbard jokes, he prefers festivals where "they pull the plug on us, so the other acts can go on." Or TV shows, where the band can put James Brown's "Hit it and quit it" edict into practice.

And he offers insight into how the Roots work, explaining that though Thompson is considered the group's leader, it's Trotter who is ultimately in charge.

"In the hip-hop game, it's the rapper who calls the shots," he says. "Ahmir can bring as many beats as he wants; if Tariq doesn't want to write to it, it doesn't happen. It's like having Frank Sinatra in there. If he doesn't like the music, he's not going to sing to it."

Given his druthers, Hubbard won't listen to hip-hop. He favors Fela Kuti and old James Brown records. And he's working to break into writing music for film. He scored Bertha Bay-Sa Pan's 2002 indie Face, which mixed funk with traditional Chinese music, as well as the 2006 documentary Darfur Diaries: Message From Home. But making a name for yourself is a challenge when you're "literally laying on a different mattress every night of the week," he says.

Does playing in a hip-hop band - even one as expansive as the Roots - feel constricting to a musician like Hubbard, who, as he points out, is as accomplished a keyboard player as a bassist?

"You do what the job requires. If somebody want you to come in and wash the tires, that's all you're going to focus on. The windshield might be dirty, but that's not your job.

"You're on tires," the bass player says, laughing. "So that's what you do, and you do it well."