Musician-Arrangers Spencer Blevins and Ray Shaw rehearse “The Worst Pies In London” with Nina Osegueda as Mrs. Lovett for Landless Theatre Company’s production of Sweeney Todd. (Courtesy Landless Theatre Company)

The progressive metal arrangements are ready for “Sweeney Todd,” the throat-slitting musical thriller that’s getting a headbanging musical arrangement this month by D.C.’s Landless Theatre Company.

And yes, Stephen Sondheim has given Landless permission to get loud with what may be his best-known and most operatic show.

“When he sends an e-mail, it’s like the Bible,” says Landless artistic director Andrew Baughman. “Every word means so much. He doesn’t say a lot.”

Landless got permission last winter to create new musical arrangements for the 1979 best musical Tony winner, a show that many theater buffs rate near (or at) the very top of the form. The Landless gang has tailored “Sweeney’s” score for two guitars, two keyboards, bass and drums thanks to a group of seven musicians the company calls the Fleet Street Collective.

The adapters split up the score, taking a handful of songs each. “I’ve served as the assignment editor,” says Baughman, who will be playing the title role when the show begins performances Aug. 7 at the Warehouse Theatre on Seventh Street NW. “I was surprised that he was open to as many changes as we proposed.”

The arrangers used the 2007 Tim Burton-Johnny Depp movie as a rough barometer for what alterations might or might not fly with Sondheim, who is famously exacting — yet whose revered musicals have sometimes been surprisingly revived in recent years. The John Doyle-directed “Sweeney” and “Company” are examples, with the actors doubling as the orchestra and playing their own instruments in both of those Broadway productions.

“We tended to find there were changes in the movie he wasn’t open to at all, and some that weren’t in the movie that he was open to,” Baughman says. “He’s so interested in telling the story. Every note of his score is there to tell a story.”

According to music director Charles Johnson, Landless has been able to massage harmonies and meter, but not the tunes. “The only thing he was worried about was some places where we went off course with the melodic lines,” Johnson says.

Does telling “Sweeney” through prog metal mean a wholesale change?

“I don’t think so,” contends Baughman, whose scrappy Landless troupe has produced rock operas in small spaces for years. “Most of us who are on board love ‘Sweeney Todd’ so much to begin with that we’ve got the feel of the piece.”

The auditions, says director Melissa Baughman, were “not traditional in any sense.” Landless started by requesting videos or sound files from actors to weed out who did and didn’t have the platinum pipes to belt along with metal. The cast of 20 ended up being a mix of theater vets alongside a few singers who front local metal bands.

“They’re either going to be able to sing rock, or they’re not,” the director says. (The two Baughmans are married.) “People who auditioned were very serious about it. When you say you’re doing a prog metal ‘Sweeney Todd,’ the lily-livered chicken out.”

She defines prog metal: “It’s really technical metal. It borrows from a lot of genres; it can go from weird jazz fusion to piano work to straight up guitar solos. It’s a thinking man’s metal. I would liken it to a classical genre — very orchestrated, very technical. Which kind of matches up with what Sondheim does.”

Johnson has worked on several traditional Sondheim productions before, but he was a stranger to the heavy crunch of prog until he worked with Landless on the metal opera “Richard Campbell’s Frankenstein” last year.

“Of all the musicals that would lend themselves to prog metal, ‘Sweeney Todd’ is the one,” Johnson says. “It’s got the mixed meters and the disguising of the beat. The subject matter is very prog metal. It was already partially there.”

Part of Johnson’s job is connecting the arrangements, a particular challenge since the score has been retooled and amped up by six different musicians. He also has to gage whether the heavy metal will annihilate the singers.

“That is one of the things Sondheim mentioned,” Johnson acknowledges, noting the complications of using amplified instruments in a small-ish space like the Warehouse, where the sound designer will play a pivotal role. “He pointed out a couple places where he was worried the orchestration would cover the lyrics.”

For Melissa Baughman, who is directing her first Sondheim show, this project is “both of my worlds coming together, finally.” The first musical she ever saw was the original Broadway “Into the Woods,” and she has dreamed of putting metal on a theatrical stage since she was a kid.

“The fact that Stephen Sondheim is so supportive means maybe I have a chance to really spread my love of metal out to the theater world,” the director says.

Johnson likewise sounds like an acolyte on a tightrope: “I want to be true to prog metal. But I don’t want to disrespect Sondheim in any way.”

Sweeney Todd

By Stephen Sondheim. Aug. 7-31 at the Warehouse Theater, 645 New York Ave. NW. Tickets $25. Visit