The attached mixer has 6 inputs: 2 mono inputs comprised of a combination input connector, MIC/LINE selector, Treble and Bass controls, Reverb and channel volume controls. The 4 stereo inputs are where you can connect all of the microphones, musical instruments and external sound sources (like MP3 or CD players). The stereo inputs labeled “CH 3/4” offer the option of using RCA with a volume control. The input labeled “CH5/6” is a 3.5 mm stereo input of the type typically found on personal music players. The “Monitor Out” enables sourcing to recording devices, additional powered speakers or mixers via RCA connectors.