Athipaul, I don't see how multiple subs in a small room "would only create nodes (peaks/dips) at mid-bass and higher frequencies".
The subs are not contributing at mid-bass and higher frequencies, so they do not "create nodes". They do smooth the in-room response in the region where they are contributing, as I will explain.
The problem in a small room is not too many room-induced peaks and dips; the problem is too few! In a large room you will have more room-induced peaks and dips bunched up closer together, and the ear tends to average them out across 1/3 octave intervals (called "critical bands) so the individual peaks and dips don't stand out - just the broader trends. In a small room, the room-induced peaks and dips are too far apart for the ear to average them out so they tend to stick out like a sore thumb. But by using multiple subs spread around in a small room (each contributing its own unique peak-and-dip pattern at any given listening position), we approximate the more dense peak-and-dip pattern that exists in a large room, and the ear's smoothing mechanism can work in our favor. I have done some simplifying in this one-paragraph explanation; you might want to take a look at Welti's paper.
Equalization is not necessarily the panacea it seems to be at first glance. Equalization can smooth the response in one listening position, but actually make it worse elsewhere in the room because the peaks and dips move around as the listening position changes, so from a different listening position the equalization may well be boosting a peak and/or cutting a dip. Multiple subs gives a more uniform response throughout the room, so that any equalization still called for will probably be beneficial throughout the room rather than in one location only.
Duke
The subs are not contributing at mid-bass and higher frequencies, so they do not "create nodes". They do smooth the in-room response in the region where they are contributing, as I will explain.
The problem in a small room is not too many room-induced peaks and dips; the problem is too few! In a large room you will have more room-induced peaks and dips bunched up closer together, and the ear tends to average them out across 1/3 octave intervals (called "critical bands) so the individual peaks and dips don't stand out - just the broader trends. In a small room, the room-induced peaks and dips are too far apart for the ear to average them out so they tend to stick out like a sore thumb. But by using multiple subs spread around in a small room (each contributing its own unique peak-and-dip pattern at any given listening position), we approximate the more dense peak-and-dip pattern that exists in a large room, and the ear's smoothing mechanism can work in our favor. I have done some simplifying in this one-paragraph explanation; you might want to take a look at Welti's paper.
Equalization is not necessarily the panacea it seems to be at first glance. Equalization can smooth the response in one listening position, but actually make it worse elsewhere in the room because the peaks and dips move around as the listening position changes, so from a different listening position the equalization may well be boosting a peak and/or cutting a dip. Multiple subs gives a more uniform response throughout the room, so that any equalization still called for will probably be beneficial throughout the room rather than in one location only.
Duke