I think where you are looking for more explanation is if it is important for room size to be around the wavelength of the schroeder freq… let me try to explain it one more time.
lets say 100 hz is the crossover freq, you have an alto flute player and a bass flute at one end of the room.
one thing though I want to clarify, its not so much as the room size as opposed to distances to different types of surfaces, materials etc. These vary based on room to room. The “room size” itself is a generic term that relates to “unhindered space” really.
wavelength of 100hz is around 1130/100 = 11.3 ft lets say roughly 12
there are vibrating surfaces located at 3ft at 45 degrees, resonating surfaces located around 9ft relatively perpendicular
the waves from the bass flute are going to hit those surfaces with partial collisions , partial collisions generate in-harmonic and odd overtones. Some overtones are pleasant , some are problematic. That is what I was referring to.
Now if there were no obstacles in an ideal world, if the room had around 12-14 feet of unobstructed passage, the collisions would generate even harmonics. It would still generate some inharmonics but overall result is a bit pleasant.
Now if the room were to be treated properly, room size would become immaterial (and room ratios with a minimum size contingency come into play more) and yes in that sense you are correct. But an ideal treatment is unlikely, budget restrictions etc.
I should have worded my premise a little differently. To add to this, I started the topic at a much more basic level , geared towards those who are totally unfamiliar with it, hence I talked about very basic stuff first. Different priorities and different orders.
As the article is developed, I will evolve it so both a beginner and an expert level of knowledge would be able to relate to it.