The Mackie Big Knob Passive monitor controller provides switching between two sets of inputs and two sets of studio monitor speakers. Passive circuitry means your audio signal will remain true to its source, while a large volume knob makes it easy to make level adjustments while you're mixing. Handy buttons for Mono, Mute and Dim put necessary monitoring functions at your fingertips. The original Big Knob has been a popular solution at Redone for years, and with upgraded circuitry and a streamlined control set, the Mackie Big Knob Passive is an ideal monitor controller for project studios. Features Passive studio monitor controller Passive electronics for ultra-low noise and maximum signal integrity Connect two sets of inputs and easily switch between them Supports two pairs of studio monitor speakers Large volume knob for easy level adjustments Handy buttons for Mono, Mute, and Dim