The Hill Audio RPX-3400 is a stereo 2/3-way | mono 4-way active crossover, designed for better sound and protection by multi-amping a sound system. With a flip of the rear side switch, the unit can be configured either in stereo 2/3-way or mono 4-way mode, while the front panel status LEDs visualize which control has which function assigned. The incoming signal is divided into relative frequency bands via precise Linkwitz-Riley filters, which sport seamlessly adjustable crossover frequencies, and offer best driver protection by their steep 24dB/Octave slope. For further protection, 25 Hz Low Cut filters are fitted in both inputs to eliminate inaudible high-energy bass content, and limiters on all outputs are provided with central threshold control. LF driver misalignment is easily accounted for by the adjustable delay control, and the typical roll-off of constant directivity horns can be counteracted with a switchable filter. To make the best use of centrally located subwoofers, the LF outputs can be summed via the “LF SUM” function, making sure that in-phase signals from all subs deliver extra gain. Mute and Phase Invert switches for all outputs make troubleshooting a breeze. Compared to digital loudspeaker management systems, the RPX-3400 is not only more affordable, it also offers greater ease-of-use and a full 20dB signal headroom that only an analog processor can provide.