There is more to "sound" than "frequency".
Otherwise, a cello play a certain note would sound just like a trombone playing that same note. After all, it's the same frequency. Aretha Franklin singing a middle C would sound just like Tom Waits singing that same note. I kind of have a feeling that most people would be able to discern those two.
"SAM" is a buzz word with audio folks, and it applies to speakers, as well. It means "Specs Are Meaningless". There is very little in a spec sheet that will tell you how a speaker sounds. You can learn from its specs if it will be compatible with a given amp, and you can learn how deep the bass goes. A flatter freq resp usually points to better sound, but the exceptions to this rule are many. "SAM".
Case in point, I remember 20 some odd years ago, when I was looking for my first "real" pair of speakers, there was a British company called Rogers that had a box speaker (I can't remember its name, but it seems it had an L, R, 3, and an S - maybe an A). Even though it had atrocious "specs" (seemingly no bottom end, seemingly no top end), reviewers unaminously praised its sound. I never got to hear one, so I can't verify if their rave reviews were justified. But this wasn't just one or two reviewers. It was pretty much across the board (back in the day when there was a wide assortment of audio rags).
Many factors play into a speaker's quality: How a speaker handles transients; how it presents attack/decay; how it responds to sudden dynamic bursts; how it keeps different instruments distinct (as opposed to muddying them up); how it allows itself to disappear; etc. You'll also hear some folks speak of soundstaging and imaging.
Well, you get the picture - I'm just wasting bandwidth at this point.