Hmm, TC's speaker is one of Voigt's pipe designs shown in his patent, ergo is what I consider a 'Voigt pipe' to be, so are you saying it's not like the seemingly mislabeled LCofN's mass loaded variant?

Even then, I guess one could argue that this variant is one also since his tapered design was meant to be either terminated into a corner to finish the horn's expansion or floor loaded to slot (mass) load it..............

GM