It was a big day for Mr. Nézet-Séguin: The Metropolitan Opera had just announced that morning that he would become its music director next season, two years early — a post he will hold in tandem with his job in Philadelphia. But he was all business, going over the “Philadelphia Voices” score and the logistics of how to perform it, asking who would join the orchestra to play Mr. Machover’s digital recordings on the keyboard.
“It’s not rocket science, but you need to be on the money,” Mr. Nézet-Séguin said.
Cutting — and Mixing — the Steak
Before he wrote “Philadelphia Voices,” Mr. Machover spent months making field recordings like the one at Pat’s and collecting a library of 8,000 sounds that Philadelphians submitted to him through a special smartphone app. “I really am committed to listening to every single thing,” he said, estimating that he had collected more than a hundred hours of recorded sounds.
Mr. Machover stands at the intersection of composition and computation — he has been a professor of music and media at the Massachusetts Institute of Technology Media Lab since it was founded in 1985 and was the first director of musical research at the contemporary music center founded for Pierre Boulez in Paris. To help organize his library of Philadelphia sounds, he used software developed at M.I.T. called Constellation, which can analyze hundreds of sound files by volume, frequency and shape, then visually display them.
“Philadelphia Voices” is the latest in a series of Machover symphonies inspired by cities. His Detroit piece, “Symphony in D,” featured the sound of a Henry Ford engine. His work about Lucerne, Switzerland, “A Symphony for Lucerne,” evoked the city’s interconnecting water systems, from the nearby Alps to Lake Lucerne to the Reuss River to the fountains that dot the old town.
For Philadelphia he was trying something new: a big choral work with texts written by young poets about democracy, Philadelphia’s innovations, its struggles, the gerrymandering that dilutes the political power of black residents, the city’s block party traditions and its sometimes arcane parking rituals. It was to be sung by more than 200 people from several choirs with ties to the city and its surroundings: the Westminster Symphonic Choir, the Keystone State Boychoir and Pennsylvania Girlchoir, and the Sister Cities Girlchoir.
Mr. Machover was initially unsure about the cheesesteak.
“In each of these cities, I’ve tried to stay away from the kind of obvious: the bagpipe in Edinburgh or the didgeridoo in Australia,” he said. “But if you find those things with the right angle it’s really important. So when I went home and actually listened to the cheesesteak recordings, I realized how very beautiful they were.”
He decided to give the sandwich a solo, accompanied by percussion.
Cheesesteak, Meet Orchestra
Last Wednesday, the night before the premiere, the orchestra and chouses gathered in the Kimmel Center for a rehearsal.
“We need to fine-tune a few moments,” Mr. Nézet-Séguin told the small invited audience. “The first moment, actually, is about the cheesesteak.”
Mr. Machover looked on from the seats, surrounded by graduate students from the M.I.T. Media Lab who helped bring the piece to life. His edited recording began to play, and a few musicians from the orchestra slowly added textures that mimicked the sounds of Pat’s — with metallic percussion instruments evoking clanking spatulas and a rainstick suggesting the sizzling steak.
Finally, it was time for the premiere on Thursday. The audience listened attentively as the local choirs evoked more than two centuries of their city’s history and struggles. Midway through the piece, the performers grew quiet. A set of 40 loudspeakers brought in for the piece played the final moment of the Philadelphia Eagles’ Super Bowl victory in February. A few members of the audience cheered.
Then the listeners grew silent as a mysterious new sound began to unfurl. As it grew clearer, there were murmurs of recognition and then a few chuckles. The cheesesteak was a hit.