I'd have to guess Paul ...
So hit me (tap on the shoulder would also be OK) when I have it all wrong;
Of course by now I'm a convict of "large enough woofer area", so this has to be my base. And in case you missed it, please read this :
Re: Bass Issue (Lack thereof);
With that (post behind that link) as the general thought, there's the THD involved and believe me, there is no single way this can be OK when no sufficient woofer surface is present, BUT (!!) at the SPL involved. Also, the lower the frequency the more tough it gets. Also, generally, each woofer rolls off under around 100Hz which is a sort mechanical self-protection (not explicit, but it's just more tough in that area, the lower the more).
THD is the factor of frequency, power applied and mechanical properties of the driver. However, I personally think that those properties are not the most crucial which already comes from them not being easy to interpret in their environment; just too many factors involved. And so :
It is only about the allowed excursion and no matter what driver and what size (like 10" vs 21") when the excursion crosses a limit (like 0.5cm) audible THD is your share. Notice that I gave the 21" as an expample on purpose because it will show you (hopefully) that some properties do matter, like the surface of 21" being too large now, and when not too heavy and slow (the mass) then too weak (but again implying distortion).
So we stick to the excursion, and now it is only a matter of power applied. Why only that ? because the lower the frequency the more power needed to create "your" SPL and thus the more excursion.
Notice : It is somewhat more complicated because I assume "linear power" in your situation which is different from boosting more at the lower frequencies. This is about the mechanical(ly implied) roll off under mentioned 100Hz and when this is not boosted the frequencies are just not there (or less there) and so they also can not distort (haha).
Now finally to the point : The bigger room needs more power to get the same SPL at the listening position.
It will not be so that the lower frequencies will get boosted because of this, but the more excursion implied, the more the lower frequencies will distort. And this is not exactly "more tight". Possibly more deep or low, but tight not.
For a cabinetted speaker it won't even be easy to observe the excursion, or better put : I myself won't be able to tell what is allowed because you will observe less excursion anyway because of the back pressure. But otherwise ? 2mm to one side perhaps for something like 30Hz.
So the difficulty here is that when you observe 1mm it can already be way too much because the driver doesn't move freely, but I can't tell and it will vary per speaker (literal) design.
You may have seen me telling how super surprised I was that with the Orelino already I was able to get out that "concert level bass" and that I could not understand how it kept on working for the room size I have; What I meant there was that I was used to my 1x 15" cabinetted (horn) woofer and there would have been no way to get out that SPL without the room being "full". So my observation was relative to that, and it now is my conclsusion that this is not about rooms getting full at all, but just about the distortion implied, never mind we don't observe it as distortion.
Lastly, the phnomenon "tight bass" I think does not exist any more for me. This is because there's always first that other phenomenon now : do you perceive the individual wave/frequency cycles. Well, you will as long as they don't wobble (are distorted) and it is clear to me that it is that what has all changed. And for something like 30Hz in a more square form this is there at 80dBSPL but just the same at 100dBSPL. But keep in mind : this 100dBSPL is the output of that 30Hz frequency and not something you measure from a voice, that 30Hz being 15dB or so down. So that this can work really seems crazy but it just does.
Long answer eh ?
Peter
