I am setting up a Connect and came upon the "Source level" setting. It wasn't immediately obvious to me how to interpret this but the most literal interpretation would be that "Source level" refers to the source level, i.e. one would set "Source level" low for a source producing low-amplitude signals (causing Sonos to preamplify the signal more) and set "Source level" high for a source producing high-amplitude signals. A second possible interpretation would be that "Source level" actually refers to the amplification to be applied to the incoming signal. The documentation does not resolve this ambiguity; I had to resort to experimentation. It turns out that the second interpretation is correct. This wasn't too difficult to work out but it was inconvenient. I would request that the name of the control be changed to "Source amplification" and/or that the information be added to the documentation that this setting controls the amount of amplification.