Christopher Theofanidis is Pittsburgh Symphony Orchestra's composer-of-the-year. Listen in The main theme of composer Christopher Theofanidis' "Rainbow Body" is based on a chant by Hildegard von Bingen: Hildegard von Bingen's "Ave Maria, O auctrix vite." Sequentia, DHM. Theofanidis' "Rainbow Body"; first statement of theme. Atlanta Symphony, Spano, Telarc. One of Theofanidis' favorite techniques is to develop music not in the traditional thematic manner, but by growing in color, intensity and reverberation. More than just getting louder, he creates energy through a complicated process of holding specific notes and orchestrating certain instruments. He calls this "haloing" or creating a "wet acoustic." In "Rainbow Body" the theme stated above expands in each of its subsequent statements using this technique. "Rainbow Body"; second statement of theme. "Rainbow Body"; third statement of theme.

Jimmy Buffett has "Margaritaville," Billy Joel "Piano Man" and Led Zeppelin "Stairway to Heaven." Big hits that still take pole position in encores but also have molded perception of the artists.

Classical music has its hits, too, such as Bach's "Goldberg" Variations or Beethoven's "Moonlight" Sonata. But they aren't all old. One of the latest is Christopher Theofanidis' orchestral work, "Rainbow Body." Theofanidis, 39, wrote it in 2000 for the Houston Symphony. It was the opportunity of which any young composer dreams.

The dream turned even sweeter when Theofanidis entered the piece into the 2003 London Masterprize competition, a contest in which the public helps to vote on the best pieces. The 12-minute "Rainbow Body" not only won, its colorful and lush writing caught the ear of conductors everywhere, catapulting it to more than 80 performances, including one by the PSO in 2005. In these days, when most new pieces get shelved after their premiere, that is an astonishing track record.

Like Buffett, Joel and countless other pop stars, Theofanidis wouldn't be at fault for wanting people to see beyond his big hit to the rest of his musical output, but that's not his style. "I am proud of it; it feels like me," he says.

Now the composer is working hard to make sure he is not a one-hit wonder, with many new commissions on his plate. The PSO has one of those. It named the Greek-American its composer-of-the-year and commissioned a violin concerto, which Sarah Chang will premiere in June.

"We met in person last summer in Cortona, Italy, at festival last summer," he says. "By the end of the summer I had given her all three movements. She has been very vocal, of course in a very polite way, she is very charming. She circled things for me early on that were difficult for her in terms of fingering problems."

It's nice to have problems like that. Growing up in suburban Houston, Theofanidis hardly knew contemporary composers even existed. "[I thought] it was a very burned out art form at that time," he said. He composed some in high school. His first piece was ambitious, for full marching band. "I guess they didn't know the proper thing to do was to write a piece for one instrument first," he says, laughing. And he ended up being a composition major at the University of Houston. He was a very close to matriculating to business school, but decided to give composing one shot by applying to the Eastman School.

		Pittsburgh Symphony Featuring: Peter Oundjian, conductor; Yefim Bronfman, piano What: Theofanidis' 'Rainbow Body'; Beethoven, Piano Concerto No. 1; Mahler, Symphony No. 1. Where: Heinz Hall, Downtown. When: 8 p.m. tomorrow; 2:30 p.m. Sunday. Tickets: $19-$72; 412-392-4900.

"I went up there and had a rough time," he recalls. "[Composer] Samuel Adler was drilling me with ear training until he just broke you down. So I came back thinking -- it is business school! But I got in and I found out it was not a dead art, it was a living art."

"Rainbow Body" may have won the Masterprize, but not because Theofanidis played to the common denominator. Under its attractive shimmering surface, it has depth and sophistication. At its core is an approximation of a melody by Hildegard von Bingen, the 12th-century abbess, author and composer called, "Ave Maria, O auctrix vite (Hail Mary, source of life)."

"Hildegard's melodies have very memorable contours, which set them apart from other [Gregorian] chants of the period," he writes in his notes to the work.

To capture this, Theofanidis created the reverberant ambience that the Hildegard chant might have had in a cathedral, a process he calls "haloing" or creating a "wet acoustic."

"If you are inside a church and you say something, the sound lingers in the air, bouncing off the walls and kept alive longer than its actual life would be because of the acoustics of the room," he explains. Since music halls are drier than this, Theofanidis "builds that effect into the music, not depending on the concert hall to do that for you."

In "Rainbow Body" the Hildegard theme grows using this technique rather than, say, the sort of thematic development that Romantic composers used. At first, some of the accompanying strings "sustain little notes for half a beat or a beat longer than the actual melody itself." This causes the melody to "thicken out" and resound as if the damper pedal were being pressed on a piano.

In later statements of the theme, the composer adds a drone in the winds and more players on the melody itself. Eventually, it expands to orchestration in octaves and brass swells.

When a piece is performed as much as "Rainbow Body," conductors tend to try out different approaches. Peter Oundjin did so with the Baltimore Symphony last year, projecting images of space taken by the Hubble Telescope behind the musicians. The PSO will repeat that when he conducts the work this weekend.

"The link was that the title of 'Rainbow Body' comes from the Zen Buddhist idea that when the body dies of an enlightened being, it doesn't decay, but it gets absorbed back into the universe as energy or light," he says. "When stars die, they are absorbed back into the universe literally as energy and light.

As to the prospect that "Rainbow Body" may be the only thing for which future audiences remember him, Theofanidis is humbled, not annoyed. "It would be a great surprise if that one piece had some legs beyond my lifetime. I would be really happy."