Wilson's new speaker the Sasha is coming.

In reference to Mariv26 -- X material is a phenolic composite (not the same as an epoxy resin). X material is indeed extraordinarily rigid and very hard -- much stiffer and harder than aluminum. The waterfall graphs are but one type of scientific research Wilson does on materials -- but these graphs (despite your assertion) are very revealing of certain aspects of a material's acoustical performance. Wilson correlates these tests with blind-test listening comparisons. Certainly for Wilson, this test alone would indeed eliminate aluminum as a serious contender for speaker enclosures. But there are several other tests that reveal that aluminum is not a particularly good material for speaker enclosures. At least if the goal is to build enclosures that have the least sonic contribution to music. And the answer to the straw-man rhetorical question "why do you not see airplanes built from epoxy?" Again, X is not epoxy, but the simple and obvious answer is mass (weight). X is much, much more massive than aluminum and therefore would be unsuitable for the construction of airplanes -- where low mass is critical.

Disclosure -- I am an employee of Wilson Audio

Wilson employs a post-grad mechanical engineer, along with an electrical and acoustical engineer -- again, both post-grad degrees. I can assure you that neither of these credentialed engineers are "mortified" about revealing this aspect (just one of several) of Wilson's science. You are absolutely correct: a loudspeaker enclosure needs to be as quiet and rigid ass possible. X-material does these two things in combination far better than any tested material to date. The science indeed clearly supports this claim.