Lower deck in front of a boat. This is the ferry between Royan and the Pointe de Grave. Near Bordeaux, France. UCS Category: BOATShip. Duration: 01:45.
Several beeps of an active sonar. This is a low frequency sonar (long range but low definition). It is a triangular wave of 1030 Hz frequency easy to put in loop. In reality, a military submarine usually has passive sonar, more sonar info: en.wikipedia.org/wiki/Sonar. UCS Category: BOATSub. Duration: 00:31.
This is a sound file to calculate the speed of sound propagation in air. Two microphones 50 centimeters 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.