Audio Input problem

[SmilebotProductions]

Heya so i was wondering how to get a good audio signal to do a demoreel with reso. Would like to use a mix i have on computer and not my mic. So i thought soundsiphon would work to give me an input internally. Have a early mac 2015 . Also would like to get audio signal at shows through my aux jack if possible. Suggestions?! Thanks in advance, Smiley @ SmilebotProductions ATL