I currently have my system using a Pioneer VSX-405 receiver and a pair of JBL HLS410 and I am using a JBL SUB135. I tried using the JBL S26 with sub but tooooo much bass and made it sound too boomy. So I decided to use the JBL HLS410 which really worked well with the sub. The sub goes low as 40hz and I tried to test it in 35hz but when the tone is at 35hz it is not that powerful since its -6db at 35hz on my sub. But at 40hz its only -3db so that's why I can hear it well on that freq. Of cource when it's 45hz I can hear that freq very loud compaired to 40hz or 35hz since at 45hz it's -0db so that's very cool. I have a program called TrueRTA so that's how I know what db is in what freq. :cool: