Pachyderm - How to connect Strength/Loudness (G)

Hello, I am using Pachyderm to do an acoustical simulation of a concert hall for my thesis. I want to know what to connect to the Strength/Loudness component. It asks for the Energy Time Curve (ETC) which I have already connected, as well as Source Power (SWL) and Pressure (P/I). What should I connect into the last two?