At first I was using the THX-optimode test, which wasn't really telling me a lot. I got AVIA a couple of days ago, and have discovered measuring the LFE 20-100 frequency sweep, that the SPL-meter indicator stays at -10 until the sweep reaches 50Hz at which point the SVS causes the indicator to go to +6 this stays on till about 40Hz at which point it goes back to 0. It goes up again, and then dies down after 26Hz. The low frequency performance is without any question, but as I understand, I have a big gap between 100 and 50Hz! That can't be right, can it? The range on the RS-SPL-meter is set to 80, C-weighting, slow response, the volume on the denon avr was set to -25. The sub is a SVS 20-39PCi It was suggested on another post that I should position the sub in my seating position, and walk around to measure the optimum subwoofer location. I'm going to try that next, but I just wanted to check if anyone has another idea to solve this thing. Thanks for any help.