Cool. Its been very interesting to me too this discussion, and I've definitly learnt from it. Hopefully others have too, if they could be bothered to read something this large :P

I have one other quick thing. As an example, the LAB12 woofer, in a Qtc=0.707 sealed box has resonance at 41Hz (thats where impedance peak is too of course). PiAligned LAB12 has Fb at 21Hz. Both have similar -3db points around 35-40Hz. Does this mean, the resonance overring on the sealed box will ring at 41Hz, and on the vented will ring at 21Hz? That would indicate to me that the vented cabinet has another advantage, because resonance is at the -10db point (about), but on the sealed box for this example, the 41Hz resonance is about the -3db point. That would seem to me the PiAligned resonance overring is at a freq greatly attenuated (by ~10db) but on the sealed box, is only attenuated 3db, which is really nothing. That also means for most music with no below 30Hz content it will be harder to make the PiAligned cab ring than the Qtc=0.707 sealed box, simply because resonance on the vented is way lower. Could this be the reason why you said in another post that a PiAligned cabinet still has less overring than sealed cab with same -3db point?

Thanks!
Adrian