You know better than that doc. The LFE channel goes above 80Hz and crossovers aren’t brick walls. A sub shouldn’t be wheezing above 80Hz like the PB16 does, and the PB17 fixes that.
I know that, and that you can set the crossover higher than 80 Hz. However once you do that you are getting into a more critical area of human hearing, and then you entering territory where a custom designed crossover is mandatory and not a receiver or AVP generic crossover. When I blend in my BSC to the long pipe drivers it is via an active crossover I have customized, just like I would for any other speaker I design.
I think it is generally accepted that the last two octaves are sub territory. I really don't like the term mid bass. As far as I'm concerned anything below 400 Hz is bass period. I would not argue if you want to extend the definition to 500 Hz. From there on out to around 4 KHz it is midrange, with the speech discrimination band being 400 Hz to somewhere between 400 Hz and somewhere between 3,500 Hz and 4000 Hz. Certainly anyone who has hearing deficits below 3,500 Hz becomes increasingly symptomatic with speech recognition becoming increasingly impaired below that, and profound at 1500 Hz and below. The ear is most critical of aberrations in and around the speech discrimination band, and that is the area where speaker FR irregularities are most objectionable and is the area that needs the greatest attention and care of the speaker designer.
In speaker design keeping the power demands across the frequency spectrum is absolutely crucial and generally not given nearly enough attention. I have the impression that this sub obsession has made matters worse, with increasing neglect of the frequency spectrum where power resources need to be devoted to.
In the UK there is now a return to basics of old, and some of the good classic drivers of even 60 years ago, being manufactured again. Good designs of those days are being dusted off and updated. One of the things that has been lacking is good large dome midrange drivers. The Dynaudio D 76 has been long NLA and the ATC dome mid kept proprietary. I am glad to report that Volt are now producing a range of really good high power dome mids. They are available in the US now from Madisound.
The reason these larger dome mids have higher power handling and deliver high Spl. is because the VC is much larger diameter than in a cone type mid. The problem is, that they are much harder to manufacture than cone type mids.