Are these Speakers the BEST on Planet Earth ?...

So many assumptions there, Bobbie!    

Of course they are!    Just ask those that MARKET them.

@teo_audio:  Save your keystrokes!      There are many posers on this site, that think they know something about Science.        All obsessively attempting to categorically prove their side of an argument, with their favorite THEORY.      Classic Dunning-Kruger cases.       Thus far, what Science has taught anyone that’s been paying attention is; there’s another side to this Mobius Strip of a universe we haven’t found, yet.                                                     Occasionally; I feel guilty for picking on them.

Plus one for scale.        When I hear complaints about systems being unable to deliver the dynamics and size of a live orchestra, I guess they’ve never heard any of the IRS Series (even the Beta), with (say) a pair of VTL 300s.               Perhaps some big Wilsons, or- Avantgarde Trios, with some stacked Basshorns.      In the right room, of course.                                 Yeah: scale!

@jmforge- The lowest Bass Guitar note is E2 (82.4 Hz).       There were/are a variety of speaker cabinets, designed to accompany the SVT amp.      Some for practice and some for moving real air, at one (individual) instrument’s primary frequencies.      Is this the one, to which you’re referring? https://www.sweetwater.com/store/detail/SVT810E--ampeg-svt-810e-8x10-inch-800-watt-extension-cabinet

@atmasphere -   Yep, E2’s low note on my guitars.     Standard Bass guitar goes an octave lower.    Conflation (touche')!

And here I thought I was doing at least one thing, in my life, that was, "normal".      ie: https://www.quora.com/What-are-guitar-string-frequencies                 Whatever Mr Cox’s goal; he hit it out of the park, with the SVT.