SubDoctor splits off the sub band with a 24 dB/oct Linkwitz-Riley crossover (no dip or bump where the bands meet) and lets you do everything an 808, kick or bass needs. Sub Enhance boosts or tames the low end by ±12 dB, Saturation thickens it without raising the peaks, and Mono Sub keeps everything below Frequency in the centre — just as clubs and vinyl demand. Harmonics creates overtones from the sub itself (2nd to 5th harmonic): your ear fills in the fundamental, so the 808 comes through on laptops, phones and small speakers. Character picks the colour: Warm (even, warm), Growl (odd, growling) or Full. DC protection, an 18 Hz subsonic filter and the Guard limiter on the output make sure a boosted low end never clips your mix. A high-resolution low-end analyser shows the sub band and the harmonics, and recognises the 808's note.