Here is a short two cycle test of latest siren, a 1920's Sterling Little Giant. This siren is currently being refurbished and will be installed at the house until the t-bolt is done. It doesn't hit full pitch in this vid, since half the brushes were so worn they were not making contact with the commutator.
http://www.youtube.com/watch?v=--maqZMonTE
I bought a 2t also but will probably wind up selling it since I wasn't that impressed with it, just an odd sounding 2.