I just thought I would share this. This is what I typed with a convo with an audio friend talking about port area recommendations in relationship to box sizes for certain woofers:
I've actually followed chamber size quite closely as I've designed. Two 4 cube chambers will resonate slightly higher than One 8 cube chamber in sealed or a 4th bandpass (any level this works). Why? The raw volume of the chamber matters, regardless of the system. Smaller chambers reach air-compression/vacuum limits earlier than larger chambers, regardless of how many woofers or chambers or sizes. It's always this way, even if all total airspaces are equal.
Like, 2 sealed boxes has 16 internal corners, where a single sealed box has 8 corners. The 2 sealed boxes will have more corners inside of it where pressure will be higher; that's not technically what I'm saying, but that's one way to think about it. The more air you add to air, the more the air can overall compress. Larger chambers have more air that can be compressed further than smaller chambers.
This is just how air itself works. It shows itself in every type of enclosure. The bigger the ported box, generally the slightly less in^2/cube you need to keep the port velocity the same. The bigger the sealed chamber, the lower it resonates vs doing multiple small chambers with the exact same airspace. Larger air volumes have more inherent compression/vacuum "stretching" ability from nature. When air bumps into to air instead of walls, the air has even more cushion to compress more. In a dual chamber vs single chamber, the air is hitting the splitter in the box and raising the pressure, instead of hitting another giant wall of air in a single chamber, where both walls of air are able to compress on each other, instead of getting higher pressure and not being able to compress because it's hitting a wooden chamber split.
Might be a word salad. I tried. You need less box volume and port area in any enclosure as the enclosure gets bigger to keep the same resonances, port speeds, cone movements, etc. It's just a few % points as you double in size, from what I've seen (I've done 16-24 cube chambers multiple times).