The DU30 is a must for any small club, restaurant, store etc., whenever paging is needed over bakcground music. It has stereo RCA inputs for the music, and an XLR and RCA input for the paging microphone or signal to have ducked under. The microphone input has phantom power available and a pad switch in case you've got a high output mic. The sensitivity control sets the threshold at which the mic will duck the music, and a Mic Level controls the volume of the Mic Input.