Are those graphs generated by Audyssey?As you saw in the previous reply, using Audysey full range is unlikely to improve sound quality.. It is generally accepted to limit room correction to the frequencies where the room dominates the response, which is below Schroeder. This is often somewhere around 300 Hz. The vast majority will have a train wreck for a response below this region...certainly nothing approaching high fidelity if that is the goal. With the phone app, you can easily adjust the frequency below which to limit correction.
No, eq won't make a good speaker sound better than a great speaker, imo. Room correction cannot correct directivity errors and poor off axis response.
DEQ will make a drastic difference in sound quality particularly at low listening levels where a flat bass response will result in bass that sounds too weak since we have poor sensitivity to low bass at low volume compared to other frequencies. DEQ does also give a treble boost as well, so not only will bass sound fuller and more balance at low volume, but upper treble will be brought forward some as well to compensate for our lack of sensitivity in this region as well. Also, its easy to push a button to turn it off when you want to. Since all recordings are different, no one setting will make everything ever recorded sound perfect. I like..no, love, having it but do sometimes turn it off.
I have found that Audyseey XT32 does a fantastic job of equalizing bass response to both speakers and subs. Most people do find that they like to turn the subs up a few dB to taste after Audyssey, but I would caution a common mistake, which is turning subs up to taste, then applying DEQ on top of that. This is indeed likely to cause a bloated bass response.
Since pictures are worth a thousand words, here is what Audyssey does for my speakers when run full range without subs(I would never sacrifice sound quality to use them this way, crossing to subs is far superior):
View attachment 3077440
Compare this with the same speaker with no eq:
View attachment 3077441
And finally, the average response across a wide range of seats in my room with dual subs and Audyssey:
View attachment 3077442
No chance of getting anything remotely close to this with two speakers and no subs, regardless of eq or not.