I've always wondered why the spl wanders all over the place as well. Even with the meter set to a slow response, the db just bounces up and down, although the test tone does not seam to get louder - by ear.

I've also discovered that the Denon 4311 sets LFE about 10 db lower than the rest of the speakers. The 3808 always got the sub pretty close. I'm totally clueless why the 4311 is setting it so damn low.