You really don't think acoustics matter?
Have you ever noticed that at away days like Leicester and Chelsea where the away end has a huge roof over it, the noise engulfs the stadium.
However at Tottenham, Arsenal and Wolves where you're on the bottom tier it's much harder to make a lot of noise.
This is down to acoustics as its the same set of fans.
In regards to the Etihad, I think our singing section works harder than almost any others in the league, but it really is positioned in the worst possible part of the ground for making noise.
This is so evident when SS3 gets going. SS3 never give nearly as much effort into singing as SS1 however they make an absolute racket when they do sing.
Where I sit in 232, people don't join in with SS1 cause they can barely hear them, but they do join in with SS3.