Good thread. Having just moved to a condo with (sad to find this out AFTER buying) paper walls, I find that 70 - 75 dB is about as loud as I can go without being a nuisance to others. This is not nearly as loud as I would like to have it.
Saturday, my neighbor downstairs who constantly complains about the "noise" (this is a guy who bangs on the ceiling when I'm playing Beethoven Cello sonatas at 75 dB at 8:30 PM. Nice guy, huh?) decided to drown me out with his stereo. I turned my stereo off, and got out the radio shack SPL meter. His stereo was playing at 75 dB in MY house. I wonder what the level was in his house?
Audiophiles, a word of advice. Do WHATEVER YOU CAN to find out the sound insulation efficiency of any multi-unit dwelling BEFORE you buy.
Cheers.