Reply to S4 and Electronic Drum Kit through live input

Hey guys me and a buddy are looking to make re edits of hip hop tracks with an electronic drum kit. Would it work to put the output from the drums through the inputs on the back of the s4 and just record straight from the S4 Recorder. What would be the best input settings. Also what we've noticed when our stuff is hooked up to the same speakers is that his kicks sort of cancel out, as if my song is washing his sound out. Would this happen in the case of the drums being hooked up to the S4.