It was a standard part of the 70mm, reserved-seat, roadshow engagement experience of the ’50s and ’60s to play an overture before the film began. When the film went into wide release on 35mm prints the overture was often (typically?) dropped. But some films used another kind of musical prelude, a kind of mini-overture that was included on all prints, even wide-distribution versions. Here’s one example on Criterion’s Bluray of The Innocents. (Sorry for the imperfect framing.) I remember attending a commercial screening of William Friedkin‘s Sorcerer in ’77 that included a Tangerine Dream mini-overture, but for some reason this wasn’t include in the restored Bluray. Michael Bay used a mini-overture for the very beginning of Pearl Harbor. Hans Zimmer‘s theme played for maybe 8 or 10 seconds on a black screen before the film began. I asked Bay about this during a Honolulu press conference in early May 2001, and he said he was proud of it but had to fight for it.