FYI in case its applicable : I work in a 5.1 environment (Using pro tools 11 HD) that's acoustically treated (by professionals of course) and my system is calibrated. My room is smaller so I find I have to calibrate to 78 in order for my mixes to come out with a dial norm of -27.
When I'm mixing, and I know the print master is going to be used to make an AC3. Do I need to mix the 5.1 at a level that ensures when the stereo fold down takes place, it doesn't clip the stereo bus? I find that I have to put a limiter at -4.5 on my 5.1 mixes to ensure this. Does this sound right?
If "yes", is a part of putting together deliverables, making an "AC3" version that's slightly quieter, or has less dynamic range?