Bass — dirt in parallel, clean low end kept

Distorting a whole bass signal loses the bottom, every time. Split it: the dirty path carries everything above roughly 120 Hz, the clean path keeps the fundamental. The KHDK Abyss does this internally — it is a bi-amp dual-path pedal, which is why it is here rather than a regular overdrive. If you are doing it with captures instead, do the crossover before the drive and check phase where the two paths meet.