Hello,
I have been running the 800S for sometime now. The only thing you do hear is the unit pulling in air, even with the silencer, you still hear it pulling air. IMO, I don't think you are going to find a dead silent HOB skimmer. They all are going to make noise, weather it be the air intake or chopping bubbles, or the humming of a pump.
FWIW, the fans on my fixture are just as loud. Everything seems to blend together after awhile...
My setup is in the living room as well. Doesn't bother the misses either!
HTH,
Brad