Ed, I am somewhat confused as to the relative ratings of the Craigsub scale over at AVS. For reference, I have posted them below: Specifically, my questions concern the performance ratings of the SVS PB12-NSD, SVS PB12-Plus/2, SVS PB12-Ultra, and the Hsu VTF-3 HO. The way I understand the scale, each point represents roughly a 15% increase in performance, and that a single percent can be considered roughly equivalent. So, my confusion is as follows: 1) The PB12-NSD (single NSD driver) and SVS PB12-Plus/2 (dual 12.3 drivers) both have the same performance? The only way I can see that is if the ratings are based partly on low SPL requirements. 2) In the thread, Craig estimated the performance of an SVS Ultra/2 as being 3 points higher than the Ultra. That would put it on par with the Hsu VTF-3 HO. Same question as #1: How is it that a single driver sub can outgun a dual driver one? For that matter, how is it that the HO outguns the Plus/2 by the same reasoning? I am assuming that the Turbo's only reason for living is to provide additional extension, not SPL. so, if the Plus/2 is running in the native tune of 25Hz, and the HO runs at 16Hz (or even 22Hz), I can see where that might tip the scale a bit, assuming that part of the ratings are base on extension, and not SPL. 3) Given what you said about the advantage below 30Hz that dual (single driver) Plus subs would have over a single Plus/2 dual driver configuration, where would you say that duals would fit in this list? Craig estimates that an Ultra/2 would be roughly 3 points higher in performance that the Ultra. That says the dual driver Ultra only represents a mere 15% increase in performance over the Ultra/2...? By extension (no pun intended), is it reasonable to say that dual Plus subs would be about a 15% advantage over the Plus/2 (meaning 90 points on the above scale, equal to a single driver Ultra?). Somewhere I read that the 12.3 driver has about 90% the performance of the (current) Ultra, but by the above scale the Ultra/2 (93 points) would have a 30% edge on the Plus/2 (87 points, presumaby in it's native tune). How does that follow? Am I all wet here? Thanx again for your expertise, and for taking the time to share your talents!