[JohnBooty]

It cannot be understated how much better even modest/mediocre speakers can sound when their in-room response is corrected via DSP.

(This is essentially why a lot of consumer electronics sound surprisingly good these days: onboard DSP is cheap and easy to implement. What a blessing!)

Conversely, even "high end" speakers can sound bad if not dialed in correctly, especially if your room is rectangular and there are a lot of reflections.