I only noticed this when Apple updated its Safari web browser last week, and I immediately noticed that the sound of MP3's playing back on the updated browser sounded significantly different than MP3's playing back on any of the earlier versions of Safari I had been using since the browser first came out. Basically, MP3's playing back on the new Safari sound crappy. I also noticed that Safari was no longer using a Quicktime plug-in to play back MP3's, as apparently that functionality had been integrated into the code of the browser. I then went to Google's Chrome browser and listened back to the same MP3 file I had on my web server, and Chrome sounded even worse with its built-in MP3 playback functionality. I then went to the Firefox browser, and noticed that browser was still using the Quicktime plug-in, and playback from that browser returned me to the good sound quality I have enjoyed before. I have since decided to switch from Safari as my main browser to Firefox, solely because of this issue, though there will probably be perks to this switch because I use Thunderbird for my e-mail.
End rant.
Nicholas