With small speakers? Not loud at all. They bottom our very easily on sub-bass where our hearing threshold is extremely high. All my testing is done in an open space with the rest of the family and dogs present. I do not do any testing that is extreme because of that.
Note that when I ran sweeps on speakers indoors at far lower levels, the whole family revolted from my wife and dogs!
It is the mid to high frequencies in the sweep that cause us to run away from loudness. Bass is not that.
Many times when I am sweeping a speaker at first I hear nothing until the frequencies go up. When I test open-back headphones, I start testing levels at 425 Hz which I can clearly hear while the headphone is on the fixture (NOT my head). I then switch to 80 Hz and it is nearly silent a few feet away. This shows the massive differential in our sensitivity based on frequency.
Haven't people run pink noise on their AVRs and listen for loudness difference between the sub and mains?