I posted a ? about a sub upgrade a few days back ,btw thanks for all the repleys,I have paradigm ps 1000 ,i was going to get a better sub or try running two, some one suggested i get a sound meter and do some testing 1st before i do anything. That sounded good to me so i got a sound meter,now hear is what im going to do , i am going to set the volume on my denon 4800 receiver at -18 and the sub gain level at +4 that is my normal listening level, on the sub it self i will have the volume at about half and the cross over at 80 , i got 10 feet of extra sub cable so i can move the sub around my listening area, im going to use u571 movie for a test disc,now what do i do, move the sub around till i find the loudest out put at the same volume level and leave it there, or are there other things to look for like where it dont rattle windows and things like that , thank you for your time