no sure how you have your mic set up ,Cross and Cross DJ doesnt have any setting for a mic ,,this has to be a rmx issue ,,
so a little bit more info as to your set up ,,and how mic is set up ..
in the U-Mix Control Pro 1,2 the mic feature is a hardware ,, in the controller,,doesnt route back thru the software ,,so no setting but what on the controller ,, not sure if it the same on the rmx controller ,,so info on your set up will clear things up