Films that focus on something to do with sound generally interest me - I like it when someone notices something and rewinds a tape to hear something again and 'bing' - some problem is solved, or discovered.
Berberian Sound Studio (2012)
OK the *entire film* is about sound, sound effects and is generally rather eerie so it scores rather highly for me :)
Edit: Just found part 1 (50 minutes) - wonder how long it will last.
Apocalypse now (1979) - interview with Walter Murch in 2000
The sound of Vietnam
How wizard Walter Murch created a soundtrack of horror for Francis Ford Coppola's "Apocalypse Now."
"One more wonderful thing about the way a helicopter sounds is that it has a different articulation as it passes by. You’ll hear five or six different things going on when you get into different spatial relationships to it — sometimes you’ll hear just the rotor, then you’ll hear just the turbine, then you’ll hear just the tail rotor, then you’ll hear some clanking piece of machinery, then you’ll hear low thuds. The helicopter provides you with the sound equivalent of shining a white light through a prism — you get the hidden colors of the rainbow. ... In musical terms, we thought of the helicopters as our string section. ... Small arms fire would be the woodwinds, I guess."
I've noticed this too - a helicopter can be rattling away when it's pointing in one direction and almost silent when it's pointing in another. I'm lucky enough to live in Blackheath / Greenwich and occasionally we get Chinook helicopters passing the heath and they do make a lovely sound.
But of course Stanley Rogers' theme tune for Apocalypse Now is also brilliant, in its own way ;)
http://www.youtube.com/watch?v=Hl_QWkvtCXI#t=03m12s (Smith and Jones).
- A history of creative sound in film (abridged) - Guardian Film Blog (17 July 2008 - assumed, from first comment, couldn't spot the date!)