JDM46 you may be thinking about my post. I said it was as good as the Epik Legend. I did a frequency sweep of the PA 150 and Epik Legend and the graphs were very similar. You are correct that neither of these subs are sub 20 Hz titans, but there response under 25 Hz will definely shake the room. In that sense, it is very usable and makes for a great subs in the under $500 range. I have own a couple of Klipsch subs and in this price range none have been better than the PA 150.
Klipsch RF 7 based HT 7.4, Pioneer SC 35, Acurus Five 200 amp, Chase SS 18.2(2), VS 18.1(2), Samsung BDP F 7500, Asus/My Book Live HPC 4 TB
Yaquin VK 2100 amp, McIntosh XR 5 speakers, Samsung BDP F 7500