Strictly speaking, the Pittsburgh New Music Ensemble plays mostly "newer," not "new" music. Like many contemporary music groups, it has a commitment to world premieres, but its core repertoire consists of works that have already been heard somewhere.

That's a good thing. A bias for premieres is as harmful to the development of music as one against them. Imagine if Beethoven's Third or Fifth Symphonies had only received one performance because of public clamoring for newer works.

PNME will pay tribute to Pittsburgh son Billy Strayhorn. Click photo for larger image. Pittsburgh New Music Ensemble Where: City Theatre, South Side. When: 8 p.m. Friday and Saturday. Tickets: $17-$25; 412-431-2489. Listen In The Pittsburgh New Music Ensemble will reprise Kevin Puts' "Einstein on Mercer Street" for its 2007 season. Here are two snippets from the acclaimed work the premiered in 2002. Bass-baritone Timothy Jones sings: From the first movement, Albert Einstein's character sings of how the media focused more on his "floating hair" than his science. Einstein is fascinated at the concepts he is developing on the relationship between space and time.

As it turns out, a highlight of this summer's PNME season -- Fridays and Saturdays from July 6 to Aug. 4 at City Theatre -- happens to be a premiere, a tribute to Billy Strayhorn. But overall, there are far fewer "brand-new" works and more tested and requested ones on the programs.

"We have done over 30 commissions just since I started [in 2000]," said Kevin Noe, the group's artistic director. "I thought maybe this year would be a time to bring back a couple that are just fantastic and that the audience has asked for." Even his most diehard patrons sometimes misunderstand the need to balance premieres with other contemporary music. "I [conduct] a Beethoven symphony a number of times and never feel bad about it, but I bring back a commission and people say I am abandoning my mission," he says.

Among the returning PNME commissions is Kevin Puts' "Einstein on Mercer Street," a brilliant song cycle about the iconic scientist that was a hit among patrons when it premiered in 2002. Puts set poems by Fleda Brown that are a fictional account of Einstein's reflections as an old man. Noe plans to record it on New Dynamic Records. "I think that it is one of the best pieces that PNME has ever commissioned."

Other celebrated non-premieres on the schedule include Mathew Rosenblum's "Under the Rainbow," Kieren MacMillan's "Voices Aside," Thomas Ades' "Catch," Jennifer Higdon's "Zaka," Randolph Woolf's "BYOD" and Reza Vali's "Folk-Song Set No. 9."

One common thread to these requested works is applause, and the season opens tomorrow with a rumination on rituals such as applause.

Albert Einstein is front and center in Kevin Puts' song cycle "Einstein on Mercer Street." Click photo for larger image.

"When people are applauding, everyone is bound by the same purpose," says Noe. "The commonality of humans is manifest in the ritual of clapping."

Steve Reich's "Clapping Music" and Michael Lowenstern's "But Would She Remember You?" incorporate clapping, while Roger Zahab's "Ohio Entelechron" (a premiere) and Puts' "Einstein" examine ritual on a more general level.

The season's second weekend has a more traditional concert format, featuring a premiere by PNME's Jeffrey Nytch, "Personal Affects," for bass clarinet and tape, and Steve Mackey's "Micro-Concerto."

The third weekend is more programmatic: "The whole night [is] constructed to look at surface versus substance -- how easy it is to be false, even to ourselves," says Noe. "It's about the internal games we play with ourselves."

David Cutler's "Superpower" finds two superheroes in costume seated at the piano. "It is the perfect example of disguising what is beneath you and [examining] the difference between what is real and not real," says Noe.

Woolf's "BYOD" examines advertiser's willingness to dissemble and the arts' increasing willingness to accept it. Throughout the concert, "gender illusionist" Eda Bagel will float in and out of the action. "She will become a metaphor for the concept of concert, brought back at different times," says Noe.

Following the fourth weekend of concerts, which bring a David Stock work, "Into the Whirlwind," to the fore, the final concerts are a multidimensional look at Pittsburgh's famed jazz man, Strayhorn.

PNME has long championed Pittsburgh composers, but Noe admits being challenged when a board member charged him to celebrate the life of one outside of the classical realm. Composer David Passmore was chosen for the project on the jazz legend.

"He came up with the perfect idea for a piece: Almost no one called him Billy Strayhorn, even Billy," says Noe. Passmore takes each nickname and Strayhorn's music as points of departure for each of seven movements in combo instrumentation. "Stray," for instance, is a fugue based on Strayhorn's material that "strays off" at one point. "About eight to nine of Strayhorn's tunes worked their way into the piece," says Noe.

Note: PNME has hired two new members this summer: percussionist David Skidmore and violinist Miki Sophia Cloud -- both with a proclivity for composing, says Noe.