Ducking
This tutorial references the patcher C9mDucking.maxpat
Sometimes you use one sound to reduce the loudness of another. An example would be the automatic ducking you hear on talk radio. The caller alone sounds loud and clear, but as soon as the host speaks, the caller is turned down. This can be done using the tutorial patcher. It’s just like the keying patcher, but with the control level subtracted from the threshold. The action of the patch is reversed, with the signal getting through the left only on the lack of control. Again, the ratio affects the amount of gain change and the threshold sets the trip point.