A -30 dBfs signal per channel will give you 75 dBspl by calibration. However, if there is content recorded at 0 dBfs, you need to play your speakers at 105 dBspl (75 dBSPL plus 30 dB = 105 dBspl theoretical).
Now most normal people do not playback their systems at full calibrated "reference level", so most of the time most people have enough speaker and power to run their systems at their normal playback volumes.
You may have a point there. Never thought of that.
Please any one clarify White House Down and tell me it is awful at reference. "Awful" meaning dialogue mixed lower then the rest of the movie. I notice this at reference level. On most cases can be harsh and hard to make out.
Edited by zero zero seven - 2/14/14 at 12:39pm