[Vader]

Josuah,

A single 16-46 PCi sub (ISD driver) was what nearly bottomed (as determined by compression, and loud port chuffing) running 12 dB below reference. After lengthy troubleshooting by Ron and I, we determined that my best bet was a pair of 20-39 PC+ cylinders (12.3 drivers). I have not gotton anywhere near the physical limit of these using the 20Hz tune, and still fear for the safety of my foundation (not to mention the sanity of my dogs). I just know that I will lose a couple of dB headroom in the 16Hz tune, and don't want to bottom these at the same listening levels. I know I am comparing apples and oranges here, as I have upgraded the drivers, amp power, port space, etc., but I am the paranoid type....

Edit: based on everything I've read about the performance of other PC+ subs relative to room size, I am really starting to wonder if I would peel the paint off the neighbors house before bottoming two PC+ drivers in a 3200 ft^3 room. And in another review here on the shack, Wayne Pflughaupt was unable to bottom an single PB10 ISD in a 6200 ft^3 room! Maybe my wife is right; I worry to much, and when I don't have anything to worry about, I usually create something!