Interesting, I will compare when I get home. However, I currently have ringtones on my phone that were made this way, and they still sound different when used as a ringtone vs text alert.Yes, if you're using Garageband DON'T send to Itunes as Ringtone. Send to itunes as a song and manually change the file extension to M4R and move it to tones. Otherwise the process of garageband converting the song distorts the sound.
So, what you are describing seems to be a different, unrelated issue.