I have the HTD LII sub and I ran the volume of the box and the port sizes through LspCad and the box tuning frequency came out to be 48Hz (50Hz in WinISD)with stuffing at 0% and the driver and amp were not taken consideration, just inputted the 44L as the volume. Actual specs: 10" driver Internal volume: 44L without amp, driver and ports Ports: 2 ports 6"(15.24cm)length 2.75"(6.985cm)diameter, flared on both ends. There is some stuffing in the box. The sub is rated down to 30Hz +/-3dB, is this even possible with a sub tuned at 48/50 Hz? Doesn't a sub freq response drastically fall off after the enclosure tuning frequency? Can someone explain why would HTD or anyone else would tune a sub so high?