The Audio Precision Eight Channel Low Pass Filter, is a passive switching amplifier. Measurement filters are designed to be inserted between the device under test and an analyzer input, to reduce out-of-band switching signal components before measurement. Used for measurement of switching amplifiers, and measurement of analog signals with high amounts of out-of-band noise. Highlights of the (APx581), include: -eight channel, 20 Hz to 20 kHz passband -Passive design for optimal performance -Custom inductors designed for power handling and minimizing low-frequency distortion -Flat response -Small insertion loss -Compatible with both balanced and unbalanced amplifiers and analyzers