Ideal room dimensions - have I read this wrong?-Acoustics Forum-Acoustic Fields Forum

hi Dennis et al,
in the research/planning stages of a new listening room build, I’ve got a fair amount of flat ground to use so size won’t really be a problem however I don’t want to go too big, want to keep the building+fitout costs inside what I can afford, and also since I don’t have huge speakers.

I recognise that the final setup/sound management will depend on materials used etc. but on reading up on the “ideal” dimensions as a good place to start I’ve come across the advice about the Bonello graph and ideal room sizes
https://www.acousticfields.com…..llo-graph/
That discussion puts forward an ideal size of 10ftH : 17ftW : 23ftL
These numbers can work fine for me but they’re on the edge of the Bonello graph so I’m assuming they’re suggested as best based on practical experience/results?

But then I found the section on low-frequency absorption
https://www.acousticfields.com…..-materials
which suggests a bunch of ideal ratios that deliver almost square rooms as being the best sizes for minimising issues in low frequencies. But the chart suggests the numbers as best for all frequencies, and the ratios are way outside the Bonello graph advice. Which has me confused as to why they’re put forward.

The question I have is whether I’m reading/interpreting the numbers incorrectly? Am I missing the reason why the Bonello ratios and the absorption page ratios are different?

thanks
Frank