Originally Posted by GregLee
I must have been reading too fast. Was there some evidence mentioned telling us about how easy it is to get 105dB peak? What sort of speakers and amplifiers or receiver you must have? Why do you say it's not easy?
According to my own math, and assuming 2 meters listening distance from your speakers (or some of them anyway,) and assuming speakers with 90 dB sensitivity, you will need peak power of over 100 Watts / channel. In loud action scenes, with many or most channels average levels going very high, it would not surprise me if many receivers would clip under those conditions. And many powered sub's probably could not hit the peak 115 dB that is called for.
Just my opinion, because I don't have the gear needed to measure peak power. Too bad receivers don't come with clipping detection.
You may have read the Audioholics article on why all channels driven is not important. There's this idea that all channels are not demanding peak power at the same time, allowing your receiver's power supply some slack.
This is not scientific, but I measured peak levels in the opening scene in Sahara for each speaker (with the others muted.) I was surprised, that in some scenes, every channel was putting out high SPL peaks. So this idea that surround speakers are not very demanding may be a bit overstated. The surround peaks may have been down 2-3 dB which is certainly lower. But they were putting out plenty of sound.
So, depending on the movie, you may be asking a lot of a receiver to produce 102 to 105 dB peak SPL at every channel say during an explosion in the movie. I am pretty sure my Yamaha RX-Z7 can't do it! (And I know my sub can't)