I used a 20hz test tone yesterday which got my spl meter up to 91 db. The sub didn't bottom or anything, it just started to sound a little strained if I tried to go louder than 91. With movies, the highest I have seen on my meter is 107db (monsters inc, toy story). I thought that I had reached 112 back when I first bought the sub last year, but I must have been mistaken because no matter how loud I turned up the sub volume (using receivers volume control or the master volume on the receiver) I could get no higher than 107 db. My room is 18 x 23 x 8 with no openings to other rooms. I used a radio shack meter using the c slow settings, and all of the other speakers were on during the movie, and turned off during the 20 hz test tone. I measured from the listening position which is about 13 feet from the sub (sub is in the front right corner. My sub is a 20-39pci, and I am wondering if I should be capable of more output for both 20 hz test tone and during movies. I love how it sounds, and it is capable of some very low loud bass. However, I have had it for close to a year and I am wondering if I should add another.