Larrry

I agree with MCH. "In the end you have to satisfy your ear." I think the SPL is great for setting channel levels with Pink noise and getting the Sub phase correct but not for tuning an entire frequency range. My NHT subs claim to 21Hz but I can't hear that low so it doesn't matter to me. My personal rule of thumb is to get the levels dialed in then pop in your favorite CD and listen at low and high volumes, adjust subs to YOUR liking, enjoy. I can always tell when something is out of whack when after listening to music at fairly high levels for 30 minutes or so it becomes less enjoyable and irritating. Usually I have the sub set to high.

Hint: If the dog vibrates across the floor or the ornaments are falling off the tree set the sub level back just a bit.