2.1.22. Knee width
The knee width parameter allows you to specify the width of the transition regions at source range and target range min and max boundaries. Inside these regions, the compressor’s gain reduction is smoothly transitioned from on to off and vice versa. Adjusting the knee width effectively makes this transition more or less sudden.
The lower knee transition begins at source min and ends at source min minus knee width. The upper transition begins at source max and ends at source max plus knee width.
Note that the target range knee width is implicitly scaled in proportion to the amount of compression/expansion.