been reading the posts having to do with the current crop of so called "super 12" cabs (Acme, Barefaced, fEarful, Baer, Thunderchild...etc.) and was wondering if anyone more familiar with the specs of these cabs can tell me which one provides the best SPL/efficiency in a 4ohm model. The reason I ask is that I am looking into adding a 1x12 extension to my beloved Walkabout 12 combo (2nd gen 4ohm silver/black version). I have no problem running it at 2ohms and would rather not mix/match cabs with different resistances with the resulting power draw mismatch. I originally imagined that I would just get a Mesa Scout 12 to go underneath the WA, for tonal and aesthetic consistency, but all this talk of super 12's has peaked my curiosity. Also, is there any fairly easy way to get a list of dimensions for the super 12's. The WA is 16.5in wide and the Scouts are the same width, so I would like to try and find an extension that was close to matching the width of the WA. The reason I am interested in a 4ohm extension is that I have read that the super 12's can tend to have a big appetite for watts (specifically have read this about the fEarful's). The WA will deliver about 500w @ 2ohms which seems plenty for any needs I have, but if the cabs are looking for more to hit design levels, and "open up" I need to consider that too. any opinions/experience to share ?