kremit - thats very interesting. I have been in very quiet places, and the lack of noise is deafening! Odd, but very true.
I guess what I was trying to get at in this discussion is that if you vent an attic (which you have to by code) that you'll loose any STC rating of the roof.
So, it stands to reason then, that your true STC rating would come solely from the way you constructed your interior ceiling.
I don't have the measurement mic and meter any more. I rented it.
I started off trying to use this little hand held sound level meter, but going outside every 10 minutes to take and record measurements, got old fast. So I rented a real one that you just set up, and it records data to like an "E-PROM" chip, then you just download the data and import it into a spread sheet where you can graph it. It was expensive, so I only did it for a couple of days, and I chose to do it on the weekend when I expected activity to be at its highest.
Rick - I'm with you on the first 2 paragraphs. Those all seem like good assumptions. You can however ATTEMPT to de-couple the wall from the trusses by resting the trusses on a pad of rubber.
Obviously complete isolation is not possible, and you certianly wouldn't want to sacrifice structural integrity for isolation, but I think doing that would achieve fairly good results.
Resiliant channel on the ceiling. Sounds like a good way to isolate the ceiling, but man, you know how hard it would be to screw drywall into an RC - on the ceiling. I dunno. Sounds tough to me. I'm sure with enough tenacity....
I was hoping mass, dead air space, and insulation would yeild acceptable results.
Remember, we're talking about the live room, the vocal room, and to some extent, the drum room. The Control Room, will truly be a room within a room and have only the floor in common to the rest of the structure. The fill under the slab in the vicinity of the control room is three and a half feet thick too!
I did plan the walls to have a certain STC: brick, air, sheathing, staggered studs, insulation, flake board and 2 layers of sheetrock, puts it somewhere in the upper 40's to low 50's.
So how do you achieve that in the ceiling?
Well, that's sort of what this discussion is all about!
On another note, if my ambient outside noise is peaking at 65db, and I build a structure with an STC rating of, let's say 50, does that mean, in theory of course, that the internal ambient noise of the structure will be at around 15db??
Thanks, everyone for all of your insightful comments.