spl

[KenMasters]

Ken,will that be a std on all AVR's?

In my experience it is.

EDIT: "Movies are mixed in rooms calibrated for film reference.  To achieve the same reference level in a home theater system each speaker level must be adjusted so that –30 dBFS band-limited (500 Hz – 2000 Hz) pink noise produces 75 dB sound pressure level at the listening position.  A home theater system automatically calibrated by Audyssey MultEQ will play at reference level when the master volume control is set to the 0 dB position.  At that level you can hear the mix at the same level the mixers heard it."

https://audyssey.zendesk.com/entries/73283-dynamic-eq-and-reference-level

[Rodney_gold]

 A +10 db increase in SPL is percieved as being double as loud , every additional 3 db spl requires a doubling of power , so you basically need a bit more than 8x the power to make the music sound twice as loud.
Its only at the 1khz range that we are very sensitive to changes in loudness and it's those mids that can hurt your hearing , 120db at 1khz at listening position is earsplitting loud , yet 120db at 30hz is unlikely to do nearly as much damage or sound as loud or make you cringe...

[MorneDJ]

Read a bit on the net. Remember that the 83 dB(C) reference level is the level as used most theaters as the correct equivalent level (sound meter on C-weight and on slow time setting). However, due to room gain it is recommended that you drop the reference level for home theater with approximately 6 dB due to the typical home listening room does not being able to accommodate high SPLs and the same wide dynamic range interference typically available to a large and treated movie theater.

If you really want to know more about optimal levels get software that can analyse your audio system. With audio system I refer to your hi-fi (speakers and amplifier) and the room itself as a separate but extremely important component. I use ARTA and XTZ, but I have heard that REW is brilliant.

Once you have that you can see how much your room "interfere" with your sound. Once you see that you will be surprised how much your room screws your audio experience.