Short basic ring sound plays before selected ringtone

[oblivioncth]

For example I have the level one doom theme (what most people think of as the doom theme song) as my ringtone. But when I get a call there is a very quick basic ringing noise for about 1/3 of a second and then it switches to my ringtone as if it went to play a default and then cut it off with mine. This gets very annoying.