What is an isolated soundtrack
 

I guess this is kind of a newbie questions. I did try to search for this topic - as I'm sure it's been discussed before - but, I had no luck. I was watching SLC Punk, last night, and in the Audio Setup portion it has the option to turn "Isolated Soundtrack" on and off. I was wondering what exactly this was.

I think that it just plays the isolated sound track along with the movie, leaving out dialogue and etc., at least that is the way it works on the blade II dvd I have

Just what it says...the music without any sound effects or dialogue. Some isolated soundtracks include commentary from the composer during the silent segments.

thanks.
 

Thanks alot for the responses.