okay, silly question but those that have this sound, are you by any chance using a headset?
When I have a headset connected, it plays the old Blackberry jingle through my headset and plays the tone I selected through the speaker. I think it does this in case you have the volume down but have your headset connected. The BB jingle that comes through the headset is so lound you can hear it even without the headset in and it sounds like it is coming from the device.
Is this what you guys are hearing?