When I removed either of the earphones, I could still here the wobble.  No difference at all actually (except of course the sound being heard in one ear and not the other).  Why is that?
Sounds like your device might be doing some extra processing. Be sure to disable any filters on your device (DTS, surround enhancers, bass boost, etc) as they will interfere with proper audio playback.
TheBittenBullet