What decibel level do you listen at? What is ideal?

80db+ is typical for me at my listening position which is 12ft from my stacked large Advents.

@audioamy +1  Double Advents!

Flashback to my college days. Great speaker(s).

45 years ago, when I spent a lot of time in movie theaters, our Dolby techs would put a microphone half way back in the seats just to right of center and set center channel at 85dB, left & right at 83dB and the surrounds at 81dB (using pink noise).

I typically set volume to a level that I think approximates as if I were there, listening live.  So yes, depends greatly on genre and setting of the recording.  That often is on the loud side because of my rather large room (and my high school background in percussion).  

I too had Advents in 1975 & then a stacked pair. They were way better than their very reasonable price would suggest. They of course had excellent bass & pretty decent mids & highs if not the most open, extended & detailed in comparison to today’s good speakers. I had Lots of fun w/ them.