I have 4 Pi's with the 2226 woofer, no subwoofers, and there's absolutely no shortage of bass. I drive them with 2A3 tubes, 3.5wpc, and can still rattle the windows. I would like to try Wayne's subwoofers in a my system sometime- I'm sure if Wayne recommends it, they are great, but I don't see them as a necessity for good 2-channel sound. What kind of amp do you have? At 24wpc, does it use 845 tube? with high B+ voltage?