Originally Posted by VG1385
I could understand if one was father away from the other, but they were all equal distance from me.
Just a quick comment...
They may be equidistant from you, but another critical factor is whether they are each equidistant from all other boundaries, as those signals sum to create the total soundfield the SPL meter sees.
At this point, if you want more detail you must leave the flatland of simple amplitude (or frequency measurements) and look at the ETC (envelope time curve - available in measurement tools such as RoomEQWizard) response sufficient to examine the more complex nature of the various direct and indirect energy arrivals that sum to create the result that you observe. I suspect you will be a bit surprised at what you learn.
Best of luck.