Mixer offers fixed I/O, pre-configured architecture, full stereo or mono operation, flexible routing and control of multiple audio sources. The CSM-21 features two stereo music inputs with gain control and clip LEDs, and one stereo output with an active crossover and a dedicated subwoofer output. A Zone Remote port facilitates connection of the CSR wall controllers, which can provide source selection and/or volume control. Source select, music level, and mic level can also be controlled on the front panel. For additional control, two logic inputs facilitate page steering and music muting via contact closure.