Just curious about how the RS SPL meter measures sound. The name would indicate that it is measuring "pressure", but I'm left wondering a few things. Is this pressure the combination of direct sound from the speaker as well as reflected sound from the surroundings? The reason I ask is that when using the SPL meter to calibrate surround settings I'm sometimes left with a perceived imbalance. This imbalanced may well by my hearing ability as opposed to anything else, but it got me thinking.

Due to lack of ideal placement opportunity one of my mains sits with a glass door within 6" or so of the edge the speaker cabinet. This provides a considerable amount of early reflection, especially in the higher frequencies. If I use the SPL meter to level match it with the other main, the speaker in question either sounds too loud, too quiet, or just right depending on the movement of my head within a few inches of center. I assume this is caused by cancellation or reinforcement due to the glass door acting as a wall right next to the speaker. What's odd is that if I try to measue this difference in percieved sound with the RS SPL meter, it doesn't show up.

I know directivity places some role in how the device measure SPL as I've observed it while rotating on it's vertical axis and it can vary by 1-2db if not pointed reasonably straight toward the speakers being tested. Not sure if this has anything to do with my observations. At the end of the day I end up using the SPL meter for initial set-up but invariably tweak slightly during playback to get optimized stereo/surround effect.

I also noticed talk about listening levels of 85db on a few threads. The other day I tried that and concluded that it is far too loud for my taste for more than just a few minutes. Not sure if this is sensitive hearing (which I definitely have), reflected sound not accounted for by the SPL meter, or distortion from playing the system at -20db (manufacturer says it should be fine at this level). Any thoughts?