I think I know the answer. AtomicPowered did touch on it, I'm reasonably sure it's the bluetooth connection with your phone. Even if your phone doesn't have an audio app open, the phone will connect with the Volt and open an audio app and start playing it. This happens to me all the time and for me it's a welcome feature. I think if you take AP's suggestion of turning off bluetooth, you will find that the condition you describe won't occur. Let us know of course!