Come hear Uncle John's orchestra (AP)

BALTIMORE - When the Baltimore Symphony Orchestra warms up a week from Friday, the musicians will be clad in their usual summer attire: White dinner jackets and bow ties for the men, white tops and black skirts or slacks for the women.

Tie-dye might be more appropriate.

On the day Jerry Garcia would have turned 66, the venerable orchestra will welcome more than 2,000 Deadheads to the Meyerhoff Symphony Hall for the world premiere performance of "Dead Symphony No. 6," the first orchestral work inspired by the music of the Grateful Dead.

Patrons will be greeted by a display of rare Dead photos in the lobby, and the approximately 50-minute performance will include a psychedelic light display.

The idea for the unusual show came from Toby Blumenthal, the BSO's manager of facility sales and a certified Deadhead, who came across a copy of the "Dead Symphony" CD and thought it would be a perfect fit for the adventurous orchestra.

"The BSO, in my opinion, can rock," Blumenthal said.

The orchestra has performed with Elvis Costello, Allison Krauss, Ben Folds and the Decemberists. The night after "Dead Symphony," it will play the music of Led Zeppelin.

But "Dead Symphony" is more than just pop songs arranged for an orchestra -- it's an honest-to-goodness, 12-movement symphony by a respected classical composer that twists the Dead songs it's inspired by in adventurous directions.

The symphony had a gestation period that inevitably recalls that most quoted of Dead lyrics: "What a long, strange trip it's been." Atlanta recording studio owner Mike Adams first got the idea after a Dead show in 1974. He began pursuing it in earnest after Garcia died in 1995 and got in touch with composer Lee Johnson, who's also from the Atlanta area.

Johnson wasn't a Deadhead before he took on the project. He likes to immerse himself in a subject before he starts writing, so he amassed a huge collection of Dead CDs that he carried around in a paper grocery bag. He ended up spending nearly 10 years composing his sixth symphony -- he has since written two more.

"I absolutely refused to rush the process," Johnson said. "This is and was a massive cultural movement. There was plenty to learn."

The Russian National Orchestra recorded the symphony in 2005, and a CD was released in 2007. But Friday, Aug. 1 will be the first time it has been performed live. Lucas Richman, music director of the Knoxville Symphony, will conduct; BSO director Marin Alsop is busy running the Cabrillo Festival of Contemporary Music in Santa Cruz, Calif.

Nevertheless, "Dead Symphony" fits in with the accessible, audience-friendly and sometimes off-the-wall programming the BSO has emphasized under Alsop's leadership. Her tenure has coincided with a rise in subscriptions and improvement of the orchestra's previously shaky finances.

Just three years ago, the orchestra had to use $27 million of its then-$90 million endowment to pay off outstanding debts. But in 2006-07, Alsop's first season as music director, the orchestra balanced its budget for the first time in five years.

In the 2007-08 season, average attendance at the cavernous Meyerhoff Symphony Hall -- which seats 2,443 -- was up from 59 percent to 70 percent. (The orchestra also plays at the Music Center at Strathmore in Bethesda, where attendance averaged 80 percent.) Paul Meecham, president and CEO of the orchestra, credits the boost to Alsop's star power and lower ticket prices -- subscriptions were made available for $25 a show.

Johnson tried to be innovative with "Dead Symphony," too. He didn't feel pressure to include the band's concert staples or its few radio hits -- he just went with the music that inspired him. The first song that struck his fancy was the strange and haunting "China Doll," which became the 11th movement of the symphony. He also includes "If I Had the World to Give," a gentle ballad that the Dead performed in concert just three times.

"That's just a classy, classy tune," Johnson said. "It didn't need much adaptation."

Surviving members of the Dead have had little to say about the project, although Bob Weir has expressed his support, and Garcia's second wife, Carolyn "Mountain Girl" Adams, is expected to attend the premiere. Dead bassist Phil Lesh, a classically trained musician who is said to be working on his own symphony, did not respond to an interview request.

"I honestly am looking forward to what Phil does," Johnson said. "I hope that his would be a triumphant eclipsing of my effort."

As for the Deadheads in attendance -- the BSO expects the concert to sell out -- Johnson thinks they'll respond well to his complex arrangements.

"A Grateful Dead listener is used to the transformation of themes, rhythms, chord progressions, every element of a song you can extract," Johnson said. "A Grateful Dead fan is listening actively. ... I expect the listener to stay on the horse and not fall off."