Amazing how men can argue forever about things that are so easy to measure

Ok, pink noise on one M60, RS on slow, C-scale

1m 82db
2m 78db
4m 75 db

Result - in a 'typical' room (basement, 18x28x9, carpeted floor, drywall) the sound attenuated at about 3-4db with doubling of the distance at 'typical' listening distances.

Somewhat slower than the open space rule of 6db. This is the room effect that John was talking about.