But the MS 309i sub does not spec the -3db range of its freq but instead just mentions 35 Hz to 200 Hz which could jolly well be its overall freq resp. BTW, the Polk DSW 500 goes down to 30 Hz (lower -3db limit) and upto 160 Hz (upper -3db limit). Its overall freq response is 23 Hz to 160 Hz.
I bought the DSW PRO500 in Feb-2008. During the U-571 depth charge scene, the Polk sub repeatedly shook the ProFX listening room!! That apart, it's musicality was very good when I played my Dave Brubeck CDs (Blue Ronda a la Turk and Take Five). Ditto with my Clapton unplugged CD too.