@almarg
Al, remember that there are two speakers, not one (+3dB). Room gain adds +3dB (or more) and I'm sitting at about 3m from the speakers equal to loss of a little more than 6dB (9.5dB?). Rule of thumb has -3.5dB error here, but works perfectly for 2m listening distance. Almost constant loudness in my room is likely because of listening angle to the speaker. When I get close to one of them the other is at an angle and when I get closer to front wall between the speakers both are at angle.
Al, remember that there are two speakers, not one (+3dB). Room gain adds +3dB (or more) and I'm sitting at about 3m from the speakers equal to loss of a little more than 6dB (9.5dB?). Rule of thumb has -3.5dB error here, but works perfectly for 2m listening distance. Almost constant loudness in my room is likely because of listening angle to the speaker. When I get close to one of them the other is at an angle and when I get closer to front wall between the speakers both are at angle.