Check this out!
http://media.putfile.com/electro-pneuma ... ello-suite
Yes, that is a siren playing a MIDI file. Read more about it here:
http://www.hornwhistleboard.com/viewtop ... f=21&t=502
That is the coolest thing I've ever seen! I think someone has you beat Eric!
BTW, someone else on that board built their own pneumatic siren http://www.hornwhistleboard.com/viewtop ... f=21&t=405