Gena, the meaning isn't clear, but it appears to arise out of an overestimation of amplifier power and speaker sound output needed in big rooms. Taken literally, of course there has to be some sound level in all parts of the room, so in that sense it's "filled". But the desired sound level at the listener's position is the relevant consideration and this can be at least roughly calculated. In addition, your own recent tests have put good numbers out and showed that even for your large room the actual power required at your 4 meter listening position was only a bit more than a fourth of what the inverse square law would require if only direct sound was considered.
