I knocked up a rough mix for a band I recorded the other day that sounded pretty decent in the control room but suckkkked once I got out to the car... It dawned on my that I have an aux input on my car stereo and that I could easily hook up my laptop and mix in there 
I'm away for business for 2 weeks so I can't give it a shot but I'm curious if anyone else has ever tried. I think it would be sort of fun

I'm away for business for 2 weeks so I can't give it a shot but I'm curious if anyone else has ever tried. I think it would be sort of fun