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.
Sound of a very large industrial switch. Like that of a shed or a very large room. Like you hear in the movies. This sound was created on a computer, with a switch noise, iron bar and reverb. UCS Category: MECHClik. Duration: 00:03.
Footsteps of a person walking down a wooden building staircase in shoes. Taking his mobile, in the first person. UCS Category: FEETHmn. Duration: 00:29.