Remember the terrific tuba part in Back to the Future? Or that really sweet violin solo about halfway through?

Of course you don't. It's probably safe to assume that no one ever bought a ticket to the movie in 1985 just to hear Alan Silvestri's score. And yet, that's exactly what more than 2,500 did Saturday night at the Mann Center. Okay, maybe not exactly exactly. But having the Pittsburgh Symphony Orchestra with conductor Francesco Lecce-Chong performing the score live while Michael J. Fox time-traveled in his little purple Calvin Kleins raised the experience considerably.

One of the things missing from the movies these days is the joy of societal accord – sitting in a big crowd of absorbed others who aren't talking or texting, but who are hugging the plot ready to burst into a unison cheer at any time. What this trend of live orchestras playing beneath the silver screen will do for orchestras isn't clear, but it's been awfully good for the movies.

The Mann schedule this summer has more orchestra nights with movies than without. Pokémon was set for Sunday night, a Lord of the Rings comes later this month. To what extent people pay attention to what's on stage as opposed to what's hovering over it will vary. But although Back to the Future is no Citizen Kane when it comes to the level of music, it was still a luxury to have Pittsburgh there playing.

The movie itself has aged well. It still manages to span the emotional spectrum from tender to thrill. Today, it brings the added wrinkle of making us feel nostalgic about feeling nostalgic. But the music doesn't have a lot of layers, effective as it is. The main theme is suitably happy-heroic – it deploys a melody that triumphs by dipping into and the now-common harmonic device of a raised fourth – and Silvestri heightens moments of terror in much the same vocabulary he did later when falcon threatens mouse in Stuart Little 2.

Players do sit for long periods with their instruments in their laps, making you wish they had crossed the commonwealth instead for Mahler or Debussy. The Pittsburgh Symphony is a first-rate ensemble, and it's good news that they've become a de facto resident ensemble of the Mann. Here, they brought dashes of romance, magic, tension and perplexity wrapped in an potent ensemble sound managed vividly by their assistant conductor, Lecce-Chong (a Curtis graduate).

More than amply amplified, there were places where it probably didn't matter much that an orchestra of Pittsburgh's caliber was present. But without them, Doc Brown saving the day atop the clock tower in the storm would not have been the tingling climax it was. It was, at the end of the two hours, a lot like taking your DeLorean to the local mall: much more sex and firepower than you really need for the occasion, but when you've got it, sometimes it just feels good to flaunt it.