Mackie Big Knob Passive benefits from a proven, bestselling design to deliver professional level control, plus source and monitor selection for studios of any size. The passive +4dB audio path ensures pristine sonic integrity is maintained throughout your signal chain. More than just a level control solution, Big Knob Passive features the ability to choose between two sources and two monitor pairs. Ideal for simple level control at a home or project studio or for integration in a large studio or group of editing suites, Big Knob Passive is the "Built-Like-A-Tank," affordable monitoring control solution.