A production of the musical "Les Miserables" can be monumental: the staging of a huge cast, prominent child roles, strong voices required for a half-dozen principal players ... and at Pittsburgh CLO, there's a week to get it all together.

So, if you're musical director Tom Helm, and you've been in that role with "Les Miz" on Broadway and you are acquainted with CLO time, the last thing you want to do is make things more challenging, right?

Well, right isn't always as straightforward as it may seem, as Javert learns in his relentless pursuit of Jean Valjean, the honorable bread thief who is at the heart of Victor Hugo's novel.

Helm and director Barry Ivans are frantically pulling together the show using nearly double the usual musicians in the orchestra while reducing the run time to under three hours. (Anything more means overtime here; "Les Miz" ran 3:15 on Broadway.)

"It's a good challenge in the sense that Pittsburgh has only had the reduced orchestrations that the tours bring through," Helm said. "They eliminate the string sections and put everything on synthesizers, so I'm jazzed about the fact that CLO is letting me use the full, original Broadway orchestration."

There will be 23 musicians, all local, instead of the usual "12 to 14" that Helm estimates were used in previous productions of "Les Miz."

"One of the main reasons I go to CLO every summer and try to do three or four shows there is the orchestra," he said. "There's no better orchestra in the country."

They'll be playing music that's become ingrained in pop culture after a 16-year original Broadway run and a recent moment in the global spotlight. That came courtesy of YouTube sensation Susan Boyle's rendition of Fantine's "I Dreamed a Dream."

"I've been thinking about his because one of my closest friends [Jacquelyn Piro Donovan] is playing Fantine," Helm said. "The other night I ran across 'America's Got Talent' and the whole thing sort of came back to me. ... I can't knock Susan Boyle because she sang the hell out of it; it was glorious. [But], the way she sang, which is to treat it like a heartfelt pop song, it didn't have the whole characterization in it."

His expectation is that the song will soar anew in its intended context. "Jackie's done a lot of shows for CLO, so I think people will enjoy both getting reacquainted with her and the fact that she's an amazing dramatic actress."

Piro Donovan is among the actors Helm has worked with before, and Robert Cuccioli has Broadway history in the role of Javert. One newcomer to the show and the music director is Kate Loprest, who made her CLO debut just last month in "Swing!" The pretty soprano was a comedic dynamo in that show, which would seem to be her comfort zone: She's played in "Hairspray," "Xanadu" and "The Drowsy Chaperone" on Broadway, and her role after "Les Miz" is the fiendish Nellie Olsen in the Paper Mill (N.J.) Playhouse musical of "Little House on the Prairie."

For now, she is CLO's Cosette, ward of Valjean and in love with student rebel Marius. It helps that Marius is played by Matthew Scott, her co-star in "Swing!" and a friend from New York.

"It's a total godsend" to play opposite Scott, she said.

One thing she doesn't find daunting is the short rehearsal time, accustomed as she is to regional theater and Broadway roles as a swing or replacement.

Helm said that not everyone is such a quick study. He told the story of his recent stint with Paper Mill's "The Full Monty," where stage veteran Elaine Stritch "was taken aback that there were three weeks of rehearsal."

Stritch asked Helm about his next show, and when he said "Les Miz," she asked, "How many weeks do you have?" "And I said 'One.' And she said, 'Are you insane?' She almost lost her mind to think that this is the way some theater works."

During the run of "The Full Monty," Loprest called Helm to get acquainted before he arrived in Pittsburgh. "She's just going to be lovely [as Cosette]," he said. "It's night and day, the style of singing [between 'Swing!' and 'Les Miserables']. But when we discovered she can do all this, we were so relieved, because in Pittsburgh, we have to pull some people who can move from one show to the other."

"That's the fun part of being an actor," Loprest said, "to play in all the different mediums. So we're going from this 1940s swing, high energy to this sweeping drama. That's what I live for as an actor."