Hi there, I recently upgraded from an iPhone 4s to the new 5s and installed the backup from the iCloud. Now I have the problem that the lock sound (when you push the sleep button) has a really bad quality, sounding like a bad 32k MP3 file. As I still have the 4s, I can compare the two devices. The 4s has a much clearer sound. I remember that I already had this problem a few months ago (being on iOS 7.0.x), but I don't know how I fixed it. I really don't want to restore the phone and set it up as a new one, so maybe someone has an idea? Thanks in advance!