This Bitwig Grid walkthrough covers how to build a subtractive crossover for multiband distortion, splitting a signal into separate frequency bands so different distortion types can be applied to each. The approach uses a high-pass filter paired with a subtraction module: the high-pass isolates the top end, and subtracting that from the full-bandwidth signal cleanly recovers the low end, giving you two complementary bands that sum back perfectly.
From there, the video shows how to route different shapers to each band independently. A simpler distortion module goes on the lows, while something more aggressive like a wavefolder handles the highs, letting the character of each effect match the frequency range it is treating.
The core idea here transfers well beyond Bitwig: subtracting a filtered copy of a signal from the original is a phase-coherent way to derive the complementary band without a traditional crossover's phase complications. That makes it a cleaner foundation for any multiband processing chain.