This is a sound file to calculate the speed of sound propagation in air. Two microphones 1 meter apart and a movie clapperboard to generate a sharp sound. Follow this tutorial to perform the experiment: lasonotheque.org/education-sonore-f4.html#propagation. UCS Category: TEST. Duration: 00:01.
Cinema projector (35mm Kinoton, FP30) vacuum without fan without lamp: Getting Started, roullage and extinction (Sound: Before mechanism). UCS Category: COMAv. Duration: 00:39.