The Filter FX Loop is a utility pedal used for mixing any external effect with your clean signal while offering filtering, level, and phase controls for further tone shaping. The Filter FX Loop works by splitting your signal into two parallel paths: Clean and Effect. The Clean path has LPF and Level controls (white knobs). The Effect path has HPF, LPF and Level controls (blue knobs) as well as a phase switch. The HPF is placed before the effect, while the LPF, Level, and Phase controls are post effect. The two signals are summed together and sent to the output. The filters can be used to alter the feel and performance of an effect. Experiment with your effects to find new possibilities.