Before working out, I hooked up my mp3 player and hit the play button, but no sound came out. There were loud women talking in the gym, so this was extra distressing. I tried several files, just to make sure that I wasn't listening to a quiet or broken file, still no music. I had another pair of headphones handy, so I plugged them in - still nothing. As it turns out, the volume was turned all the way down. Why that was my last guess instead of my first, I don't know.