Song of robin, a garden bird. He cries from a tree, spacing his songs for 2 to 3 seconds, then stops, changes his tree and starts again a few dozen times and so on around his territory. UCS Category: BIRDSong. Duration: 00:03.
Telephone tone when the phone rings in Europe. This is a sound wave frequency of 440 Hz sinusoidal. This sound is easy to loop. UCS Category: COMTelph. Duration: 00:40.
Several beeps of an active sonar. This is a low frequency sonar (long range but low definition). It is a sine wave of 1040 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: 00:21.
Beep used to censor. This sound was made on a computer. It is a half-second sine wave with a frequency of 1000 Hz. UCS Category: BEEP. Duration: 00:01.