There are 3 selections for the center speaker output: music only, microphone only or music plus microphone audio output. [12]Microphone Effect Volume Control- To control the effect volume of microphone. [13]Master Microphone Volume - To control the master volume of microphone inputs. 456101112971683181714131215192021 [14]Master Music Volume- To control the master volume of the music. [15]Microphone inputs #1,#2 and #3 [16]Input Selector- To manul select input sources amount BGM,VCR,DVD,AUX, and