Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Mine is fine for most songs, but some have a little distortion. I just use sound check to set them all at the same level to "fix" that problem.
 
For what it is, my speaker is just fine. I will use it for games, but if I want any significant fidelity I listen through earphones or lug into my car/home stereo system.

You need to listen to the speakers of other iPhones before you can ask if your experience differs from the majority. Of all the features of the iPhone, I don't get too hung up on such an insignificant feature like the speakers. I don't like the speakers in my MacPro, but that was not a deal-breaker for me in purchasing a desktop system. You have work-arounds - use them.
 
The speaker on my iPhone sounds extremely bad at high volume too.

I wonder if I should exchange it for a new one, if possible.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.