I'm sure that HA is not the best forum for this dicussion but perhaps someone here knows the answer or can point to another forum.

What software do DJs use to take a WAV file (say, Green Day's Blvd Of Broken Dreams for example) and isolate a specific instrument, such as the drums or the vocals in order to lay just this instrument over a different song? I heard some great mash-ups in Vegas and was wondering what software can be used to do this.

Garage Band allows one to lay different instruments together but how do you ge tthem isolated in the 1st place?

you cannot isolate specific instruments from a stereo track (although, sometimes you can isolate vocals, if they are centered in the soundstage). You would have to buy the permission to use the individual recorded tracks for mashing up/remixing tracks.

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