I'll agree with your suggestion to adjust speakers' levels with the same frequency by the SPL meter. You can get an idea on subs, but definately listen and set it more by ear. I adjusted my sub according to the meter and it produced more low bass than I wanted so I had to cut it back a bit. Music sounded off and DVD's had long spells of just rumbling bass way in excess of what should be. Instead of adding feeling to the effect it just distracted from it. Turning the sub down about 3-4 db below what was measured on the meter seemed to give a more realistic measurement. I'm probably going to move my sub from it's corner location and redo the calibration test. I think it's not the best placement for midbass. The lowest frequencies may be getting too much of a boost in the corner. In any case, there is a strong need to adjust the sub's level by ear because of the large difference in perception of LFE's and room placement.