I've recently setup a new Sonos Amp and noticed that loudness was on by default (as someone has already noted here in a review), and also that the sub was turned on in advanced audio/sub settings despite no sub being connected.
I wonder if having loudness on by default is the best option, given that it's possible many users will have relatively high-quality speakers attached to the amp?
I also wonder if having the sub setting activated makes a difference to the sound if no sub is connected? I would have thought this setting would be disabled when no sub is connected. At the moment it is possible to toggle this setting. I haven't got around to a listening test to see if it actually makes a difference.