shady, thank you for posting the charts and also providing an analysis. I would like to better understand how to read the charts. From what I understand you were comparing MAX PASS SPL levels at different frequency points. Here the criteria seems 'the higher the better', with 6 dB being a doubling is perceived loudness. Correct so far? What else is of importance? What about the color coding?
I would greatly appreciate if you could provide a bit more insight here.
My SVS Ultras have the earlier BASH amps. I believe they have some 700 W or maybe 800 W, not 1000 W, what Ricci measured. Is there a way to assess in what way this would reflect in above charts?
You are correct about higher numbers being better, and 6 dB being a doubling of loudness. Regarding the color coding, green means the sub stays relatively clean at it's highest output level. Yellow means that is the output level the sub can reach before distortion goes over permitted CEA2010 levels standards. Red is simply how loud a sub can get when trying to play back a certain frequency including any distortion.
One thing I should add is that to fully double the loudness of a sub by adding another (basically adding 6 dB), you have to co-locate the subs, by that I mean you have to place them together, either right next to each other or right on top of each other. The further apart they are placed, the less their total output will be summed at your listening position, until the second sub can only contribute 3 dB. Spacing the subs does bring other advantages though. The room acoustics can cause peaks and nulls in the frequency response, and by co-locating the subs, you are reinforcing the peaks and nulls. Spacing them apart can tame the peaks and shore up the nulls, which is many cases is better than simply increasing total output. You have to take care of where you place the subs for the optimal placement though, they can't simply be set apart for the best result on the frequency response. Each placement has to be measured.
As for the SVS subs, there wouldn't be a tremendous difference between the BASH amps and the Sledge amps. Maybe a couple dB here and there, but the comparison between them and the sealed 18"s would still hold.