Actually, my Salon2’s have changed my thinking on subwoofers a lot. When testing 20hz - 100hz REW sweeps at 100db via my Salon2’s full range, I’ve measured
less distortion from the Salon2’s 6x 8” drivers than from 2x 18” Rythmik subwoofers. It might have been just because the subwoofers were placed closer to a wall and was causing more door/wall rattling issues, but still the results show that you can get amazing results from many smaller drivers - big single drivers are not necessary.
But more than that, I think multiple small drivers in a tower are actually much better than a single large subwoofer driver! And this matches both theory as I understand it, and my observations so far.
To this day, I still have not achieved a more consistent in-room bass response with two subwoofers than with just my two Salon2’s running full range. The Salon2 towers, whether or not their optimal stereo placement is best for bass, still has achieved in every room so far (4 very different rooms) better sounding bass than any 1-2 subwoofer system I’ve heard — more smoothly integrated, more consistent sound between different listening positions, etc.
I suspect this is precisely because of the large vertical range covered from bottom to top — from the bottom port, to all three of the 8” bass drivers per speaker. For approximately the same displacement as a 12” subwoofer per speaker, you cover (between the port and 8” woofers) a far larger region of space, which I understand should have the effect of helping to physically smooth out abrupt nulls or peaks in the room.
I find that abrupt changes in bass frequency response has an effect far more important than just making it sound good to multiple listeners. I don’t know if it’s because I naturally will rotate or move my head to some degree while listening, or the space between ears, or the tactile sensation differences that would result from head to toes, but I find that more consistent bass response in-room is very noticeable even to a single listener in a single position.
TLDR: I think more small bass drivers are better than fewer large bass drivers, since it’s extremely important for bass sound quality that the bass response be as smooth as possible throughout the room. Of course, multiple big bass drivers is even better still
But not everyone could manage the space or aesthetics to fit 4-6 subwoofers in their room. So there is something to be said for towers / line arrays of woofers.