KDB - Kick Da Bass
This combinator acts as a filter to your bass and allows you to lower the volume of this bass using the audio signal of a kick drum, like a sidechained compressor, but only for low frequencies and with no compression. So this lets pass "high frequencies" of your bass without any modification.
This will let pass the low frequencies of your kick drum over your bass while preserving high frequencies of your bass.
To use it you need these free rack extensions :
Let Reason plug the KDB combinator as a filter for your bass.
First click on "Show devices"button and hit the tab touch to show back side, then plug your kick audio parallel output to the MClass Stereo Imager audio input named "KICK SIDECHAIN INPUT".
Now use rotaries to control how the kick will lower your bass like any sidechain compressor will.
You can show more controllers when you show devices, like the range (how much the volume will be lowered) and the well-known dry/wet to simulate parallel compression.