Unreal this thread. I find it so odd that people claiming to be scientist resist experimentation so much . Makes me think of my own biases and how they elude myself...
Well. At this point I am pretty sure the Soundpath works to remove vibrations, without personally having tried them. I have a SB-1000 and a SB-2000. The latter really vibrates when movies go off with explosions when close to reference levels. To assert that most vibrations come from sound energy through the air is not having measured the movements of the sb-2000 or a more powerful sub that does not have dual, opposing woofers.
I also find it odd that people cant see a difference in frequency response when testing/measuring close to reference. The vibrations/trattles MAKE SOUNDS, and they ARE NOT SUBTLE. How is it they dont appear in your FR charts?? Are you looking for difference in the actual output of the sub or are you looking for differences in the whole spectrum?
On a side but related note, keep in mind that a few pages after "2+2", things tend to get less precise. It's more about approximation. WOW.