Mine rattles and im pretty sure its with the speaker, something loose, maybe the housing to channel the sound? Anyway thats the only place I could find any vibration coming from. It also seems to be alot more noticable when on speakerphone then when playing audio from the music player. In a few weeks I will pull off the battery cover to take a look inside and then go to the rattle and use a dot of locktight to stop it, or a tiny strip of sticky foam. From the teardown it appears there is no warranty void if removed stickers.