I ordered from Ascend. The date on the sticker says 3/11/2005.
I haven't figured out what it means for a subwoofer to be "tuned". Using DVE frequency sweeps, I can start hearing the sub at around 15hz. The sweeps are too fast to measure well with my Radio Shack SPL.
I don't have any complaint with the sound -- to my ears. It's just curious that the design would change. Now at least I know what they're talking about when they say to "plug one port".
My tape measure says the single port is 4" diameter.
The area of a circle is 2*pi*r^2 or pi*d^2 / 2.
The area of a 4" port is 8*pi; the area of two 3" ports, combined, is 9*pi.
probably also have to consider the diameter of the flare. I thought I read somewhere that the 4" port with flare has the same flow as a dual 3" ports with flares.