- Another beginner question. I've got a mixer with two aux sends (MONO) and a pair of stereo returns to go with them. I've also got two effects processors that take stereo input and have stereo outputs. From the other "low end" mixers I've seen this seems to be the standard (mono aux send, stereo aux return). Why when most effects take stereo inputs? How do people usually use these? I did rig up to send stereo by sending aux 1 out to the L in of an effect, and aux 2 out to the R, and then fiddling with the return levels to essentially get stereo aux out and in, but is this ok/normal/useful? Any guidance is appreciated. Thanks all