The One Minus X Node is a simple Node that performs the mathematical 1-x operation. It’s a simplified alternative to using a Subtract Node.
The audio or control signal to subtract from 1. If nothing is connected to this input, it’s the same as if a constant 0 signal was connected, causing the output to be 1.
The input signal subtracted from 1. If there is no signal connected to the Audio/Control Input, this output is always 1.