Paul and/or BHK--BHK-amp coupling-cap high-pass-filter point

First, pls understand that I’m no engineer or technician, I’m just an interested hobbyist trying to learn something, and I’m not trying to 2nd-guess anyone.

You’ve indicated that the coupling caps’ HP-filter point is 0.16 Hz…

  1. Why so low a frequency?. The ‘experts’ I read indicate a more-than-adequate filter point is about three octaves below the lowest-audible frequency one wishes to hear… If the latter is 20Hz, the former is 2.5Hz… If the latter is 10HZ, the former is 1.25Hz… Obviously, 0.16Hz (and 0.15Hz in the Stellars) is WAY below that… Advantages?. Disadvantages?

  2. Does the NFB loop include the frontend and its coupling caps?. Would changing the couplers to, say, 0.1uF for a 1.6Hz HPF be adequate to avoid both most of the energy of infrasonic pulses being passed to the amps’ output sections and hence the speakers and at the same time having no phase errors in the audible band?