It sounds like the DVD just didn't get much of a surround effect put on it. For an outstanding music DVD, try one of the Eagles offerings. I have the Farewell Tour from Melbourne and it is a great DVD to show off the surrounds, sub, the entire sytem.
I have the Eagles "Hell Freezes Over" and their "Farewell Tour"
They are brilliant for showcasing surround sound.
I really like Pink Floyd and was looking forward to watching it in all the surround sound glory, but it was very disappointing.
While the concert itself was excellent the sound was just not there. At first I thought I had done something wrong with the settings but it is just the DVD
In regards to the SPL, this is how I used it...
I mounted it to my tripod and placed it on the chair I sit in, Switched it to C Weighted and Slow.
I then started the DVD, which has an AV setup with pink noise. I had the SPL facing the center speaker and starting with the left speaker I set the volume to 80db according to the SPL, then I went to every other speaker and changed the level setting on the AV until they were all around 80db.
The AV setup said to have the Sub about 9db louder than my speakers but I cannot get it that high as it sounds like crap.
I am unsure of the sub and how to set it up, I will take some pics of the subs back panel today, I want to make sure I have it connected correctly as it has to options for connection.