TheZhe has released TheSplit, a free multimode splitter plug-in, in VST3/AU format for macOS (M1 Apple Silicon supported) and Windows.
TheSplit splits a signal into two complementary outputs via four modes:
1.) C&S: "Center & Sides" mode uses a mid-side algorithm to split audio in the spatial domain.
2.) L&H: "Low & High" mode uses a crossover to split audio in the frequency domain.
3.) A&S: "Attack & Sustain" mode uses a transient splitter to split audio in the time domain.
4.) L&S: "Loud & Soft" mode uses a gate to split audio in the amplitude domain.
Price: Free.