Ridthaler – From the inventor of the RiPol bass loading comes this active subwoofer crossover [€1'550]. It's a dual-mono purely analog device with 41 corner frequencies for its hi/low pass. Those filters operate between 50-250Hz on a 4th-order 24dB/octave slope and add a subsonic option. That may be combined with an infrasonic EQ that itself is ±6dB adjustable in 1Hz steps between 1-40Hz. There's selectable RiPol correction as a notch filter to combat chamber resonances and the entire circuity can run fully symmetrical via the mono XLR input. Over RCA the device can feed two subs. The high-pass operates at unity gain, the central pot controls the sub's relative volume. A 24VDC power supply is external. The crossover box measures 22x7x29cm WxHxD and weighs 1.9kg. RMS list as co-developer for its circuitry and this precision active analog filter obviously isn't limited to RiPol/dipole subs but may be used with subwoofers of any type and stripe.