Could I use the built in sound card in my macbook to perform live on a professional sound system?

I've been using Ableton Live lately to DJ and manipulate tracks. When I've seen people preforming laptop sets they usually route sound through an external soundcard. If I plan to to use Live with a professional sound system (i.e. a small club setting), should I invest in an external sound card or would an 1/8th inch to RCA jack directly in to the mixer do the job?

Could I use the built in sound card in my macbook to perform live on a professional sound system?
If you are just starting out though, get the RCA output (it's cheap), then consider an external sound device later. Don't skimp on the cable, and be wary at places like Radio Shack, often times they provide a 1/8th to Mono, and depending on your mixes this may not be optimal.





You may find that the level out from your Macbook is a little low, forcing them to crank the mixer up for the house system, so give yourself extra time the first time around for a decent sound check.