Music problem.

[chiko]

Has anyone had two or more music tracks playing at one time? I was playing a game and I had changed Eras and the background was playing the music from the prevous Era and the current Era at the same time. I know that you can have more than one track playing with different players, but this is weird.
Also it does it with the movies(?), like the main menu and the intro of a new game at the same time. Is this a problem with the game or is it a computer(sound card) problem?