Sound test
From Sonic Retro
Sound Test is a function built into the options screen of many video games.
This function was originally meant to test whether the game's music and sounds would function correctly, as well as giving the player the ability to compare samples played in Monaural, Stereophonic and later Surround sound. Nowadays, the Sound Test functions as little more then a jukebox to just listen to the game's music for enjoyment.