I was riding a pretty loud Spinergy Xaero freewheel hub for a while, but a crack in the rim put me back into my old Alex 295's. The Alex freewheel is so quiet I can barely hear it. It was kind of strange at first but now I like it.
Most high quality freewheel hubs seems to be reported as being pretty loud. Which good hubs/wheels are quiet too? I am considering buying new wheels in the $500 price range.
This also brings out the question, why are many freewheels so loud anyway?