I agree.
Good subwoofage is worth the investment. Polk Subs (and Klipsch, DefTech) are not where it's at.
Multiple Subs, placed smartly in your room, will give you very good SQ across all of your seats and then some. Whether opting for multiples or not, the other benefit of getting a Sub that operates cleanly and with plenty of headroom is that it tends to "clean up" (somewhat) your overall sound.
(Surprisingly, what most people complain about in 'too much' bass is distortion rather than actual bass... distortion is what causes many low level rattles and annoys the sensitive (i.e. significant others
). Good, high quality bass, that which is clean, linear, free from distortion can actually be quite subtle... until you tear down the structure around you!
)
Beyond that, Speakers are the other major point, and frankly THE most important for SQ. Your front 3 should be the most solid you can get. Surrounds can be important, but the importance in most usage is limited (unless you are supremely picky and listening actively/critically to multichannel music such as a discrete 5.1 mix rather than simply upmixing stereo or streamed content).
Your room is large enough that you could possibly employ some Rears so long as you LP is placed properly in the room and not putting you up against the wall and those possible Rears...
However, I would focus first on getting the best quality out of your current set up as possible.
The Polk Sub is the weakest link in your system.
After that, working with positional EQ to maximize everything else can lead to some significant gains in your experience, with zero to minimal expenditure. Positional EQ is making certain that you are correctly placing your Speakers and listening position to maximize their ability.
Some common, and some of the best, advice I can share is to get the best Subwoofer you can allow yourself to afford now. If you can afford two of them, do it. otherwise, save for the second and get that next.
Use free techniques to begin maximizing your room and other current equipment.
Then, and only then, consider expanding to a 7-channel bed-layer, or adding atmos. (I have seen many experienced cats recommend going for a well implemented 5.x.4 system rather than a 7.x.x.
Happy hunting!
