A sentiment I see repeated over and over here is a lot of folks that don't use subs state that their tower speakers provide "enough" bass and they don't need more, so there is no reason for subs.
Although it has been repeated many times, subs aren't about "more" bass, its about "better" bass, and hence better sound quality. It's very easy to glance at any of the in room responses of the speakers Amir has measured.....in room response is horrible below a certain frequency. +/-10 dB swings in response does not produce good sound quality. A pair of well placed subs along with eq on both the speakers and subs provides substantially higher sound quality than two speakers without subs can ever produce.
Yes, in addition to higher fidelity, subs provide drastically better capability and the ability to boost lower frequencies to compensate for our lack of sensitivity to bass at low volumes through the use of DEQ. Also, for dual purpose systems in which folks want to both watch movies and listen to music, a good pair of subs is necessary for accurate playback, which is the intention.
Yes, subwoofer advocates have been saying this for years and years so I'm aware of the arguments. I've also heard many systems with subwoofers (by people who have put a lot of effort in to the set up) and have never come home to my own system feeling I really need subs because my system just doesn't sound good compared to that system. In fact I tend to be made even happier with my system, which usually sounds to me more effortlessly coherent and integrated top to bottom.
I also went down the sub "rabbit hold" and bought JL 110E subs and the JL crossover. I have not, at this point (which is preliminary) felt the subs added enough to my system to justify the added expense, cables, speakers, hassle, and lowered aesthetics (I frankly hate subwoofers, aesthetically). I haven't fully decided not to use them as I could devote more time to integrating them even better. But that's one of the off-putting issues I (and others) have with subwoofers. When you read the literature from subwoofer advocates, it's amazing how much time and effort they have often put in to dialing in their subs to finally get perfect integration and room response. Tweak, tweak, tweak...it rarely seems to end.
I'm just not that motivated because the sound without subwoofers in my system is so damned good.
Many of us are in this hobby with a focus on sound quality.
I'm afraid a sentence like that comes off as sort of audiophile-virtue signaling:
"Those of US who use subwoofers care about sound quality; by implication those without subwoofers don't."
I'm pretty sure all of us here care about sound quality. I think I have an inkling myself. ;-) I find my system to have beautiful, smooth, evenly balanced sound, tight bass, the whole shebang. Could it be even better? Sure, few systems couldn't be improved to some degree, at least objectively. But is it "low fidelity" sound owned by someon who has no focus on sound quality? Not by a long shot. It sounds fantastic (not just in my opinion, but in that of a number of people who work in pro sound - I'm in the industry - who have heard the system).
Subs provide much better sound quality than two channel.
Sure. For you. (Note "much better sound quality" has a subjective valuation component).
I have no argument against integrating subwoofers. The theory is certainly sound, and insofar as someone achieves beautiful integration in practice, that's great. But I've heard enough subwoofer set ups to infer that integration...to the degree I find good enough...is not easy to achieve.
And then the results, in the sense of the user's subjective experience, are subjectively evaluated. A bass node or resonance may look bad in objective measurements, but may either be subjectively less so, or may be excited only occasionally given the musical material, and not be a "big deal" for a user. So we may disagree on "how much better" subs make one or another system sound.
I plan to give my subs another whirl, but it's more out of interest and playing with the system, vs feeling any dramatic need for "more/better" bass.