Typically, 0 db on your AVR is used for Reference Level at 83 db on your SPL with proper calibration tones. That is how I calibrate mine. I have seen some people use 77 db and even 75 db for Reference as well.
After experimenting with all three (3) levels, I personally use 83 db for Reference at a 0 db setting on my AVR. This seems to work best overall.
Listening at a a lower volume is fine ... I typically listen to my system at a setting of -10 db to - 5 db on my AVR if I am "engaged" in the film ... which means I am actually watching a seriously good film on Blu-ray.
I watch TV, or chic flick when my GF whines enough about wanting to watch one, at a different level. Typically, this a less engaging type of viewing experience for me, so I set the volume to -15 db to -20 db. I am often just watching something like Top Gear or a Documentary on or some other program on the BBC-HD or Nat Geo HD Channel in a more casual mode.
However, 0 db / 83 db - Reference Level will assure you are within the design limits of your system and avoid any "clipping" or "overdrive" of the pre-amp stage or amp stage of your AVR.
Ideally, for best results and ideal performance, I always try to operate my equipment in the sweet spot of its design parameters. Achieving harmony between the pre-amplification stage and the amplification stage and having just the right amount of drive in each stage can make a difference in sound quality.
Not enough drive or too much drive can affect performance and sound quality of both solid state and tube components. Electronics can be funny that way.
At least that has been my experience over the years ... but I am a constant tweaker / tester of gear ... so I am used to noticing such differences.
Originally Posted by Mr.G
I guess this has not been explained to me, what does setting your AVR to 0 accomplish? I set my Denon master volume -20 and balanced my speakers to 83 dB, the fronts needed a +7 dB boost and the rears +9 dB. If I had started at a master volume of -10 then theoretically I probably would have needed to cut the fronts by -3 dB etc. If I had started at 0 then the trims would have increased to -13 dB etc. so I am not sure what the benefit is. As long as everything in the system is balanced to 83 dB (subwoofer 86 dB) what difference does it make where you start from?