Hip-hop band the Roots rehearse at NBC Studios on Thursday in New York. (Charles Sykes/Associated Press)

The Roots are making sandwiches.

The band is holed up in a Manhattan studio, preparing for their new gig as the house band on Late Night With Jimmy Fallon, the NBC show that will take Conan O'Brien's place when O'Brien moves to The Tonight Show.

They're working long days to create 200 "sandwiches" or "beds" — the intros and outros that will buffer each segment on the show.

"Right now, my whole life is this show," said drummer Ahmir Thompson, better known as ?uestlove, in a recent interview as he lazily adjusted his pick in his trademark Afro, slightly exhausted in between rehearsals.

Since forming in Philadelphia in the early 1990s, the Roots have been one of the best-regarded bands in hip hop and music, altogether. They were one of the first hip-hop bands to take up instruments and under the steady pounding of Thompson they've been an acclaimed act for nearly two decades, with respectable (though not huge) album sales.

So when word got out that the Roots would be following in the tradition of Paul Shaffer and Kevin Eubanks, the blogosphere and much of the music world erupted in say-it-ain't-so shock.

Echoing the comments of many, Gawker.com wrote that the band "opening up for Jimmy Fallon every night is the cultural equivalent of Miles Davis playing his horn on the subway platform."

?uestlove has heard the warnings about the Roots becoming a late-show band. He says his friend saxophonist Branford Marsalis — who abruptly quit his gig as Jay Leno's musical foil in the early 1990s — cautioned against the move: "You'll be neutered!"

But ?uestlove said the band's new job has "enabled us to survive.

"This would basically match or surpass what we would make touring 200-plus days out of the year. And, two, this allows us to be home," he said.

It's a welcome respite from the road for a band that has always toured extensively. The band — most in their late 30s — are looking forward to living like "normal men," ?uestlove said.

"Initially I was a little leery," said the Roots' MC, Tariq Trotter, or Black Thought.

"I initially was thinking, 'Is this just going to be ammo for some other rapper to try to dis me for?' Like, 'Your career is so over now. You're a house band for…' You have to be that many steps ahead of whatever move you're going to make."

Performers feel economic squeeze

The idea gradually sunk in, though, Black Thought said, "the further we were sinking into economic disaster." When the economy went into recession, ticket sales — their chief source of income — started to slow. And with album sales tanking and the industry in tatters, acts throughout music are considering different ways to make money.

"It was just sounding better and better as the months went on," said Black Thought. "The pros outweighed the cons."

But the job is already more than the Roots bargained for. NBC isn't paying for publishing rights — not even for the Roots own material — so the band is left having to create a new TV-ready repertoire.

"It's going to be a major challenge," said ?uestlove. "Right now, we're writing about 25 a day. I'm surprised we're not running on fumes."

Fallon, the former Saturday Night Live cast member, has repeatedly touted having "the best band in late-night." The idea came from Fallon's friend Neal Brennan, who had worked with ?uestlove when the latter was music director of Chappelle's Show on Comedy Central.

Fallon described pitching the band while they gathered in the office of Lorne Michaels, the executive producer of Late Night: "Number one, you will raise the bar of what a house band is, because you're the Roots and you're amazing.… No. 2, I don't know who to compare you to. You can play with Tony Bennett and on a separate occasion play with Jay-Z and it works.… Third, you live in Philly, so it's an hour on the Acela train."

There are other upsides, too. The Roots will certainly raise their profile and attract new audiences. They will hold a residency at New York's Highline Ballroom playing weekly shows and will continue working on a new album.

They'll still have 10 weeks off to tour farther afield than the New York metro area. And being based in New York will help ?uestlove, a frequent producer of acts like Al Green, D'Angelo and Common, to get back in the studio.

Genre stretching

Seeing hip hop regularly on a late show will be revolutionary in itself, but the Roots are more than a hip-hop band. Their debut Do You Want More?!!!??! had an obvious jazz influence. The group may be best known for their Grammy-winning collaboration with Erykah Badu, You Got Me. Their hit off their 2002 disc Phrenology, performed with Cody Chesnutt — The Seed (2.0) — is one of the best rock songs of the decade.

They've toured with the Dave Matthews Band, joined The Colbert Report in Philadelphia and played backing band for the concert film Dave Chappelle's Block Party.

"We're going to cover every genre, though I doubt we'll do bluegrass," said ?uestlove. "This is a chance to really show people how diverse we are."

The gig is most awkward for Black Thought, the band's frontman. He'll mostly spit a quick rhyme or sing a couple of lines, but that will be it. And anything that he sings or raps on air — as well as any music played — will immediately be owned by NBC Universal.

"I didn't realize how difficult it was going to be until yesterday," said Black Thought. "It's not the blind cakewalk that I originally foresaw this gig being."

Practising, the band slips easily from one style to the next and appears to be relishing being such sonic chameleons. In one sandwich — a poppy one, or as the band calls it, "a Subway sandwich" — you could close your eyes and think you're listening to a more soulful U2.

One more bumper wrapped and ready for TV's newest sandwich-makers.