ehhh.....might be the video compression but sounded a bit hollow to me.
I think that was a live version of the song. That might explain a bit of the hollowness. However, I still don't think it was a very good test. A (presumably) live version of Rolling in the Deep, recorded by another camera in a video uploaded through Youtube.
I thought the speaker put out a pretty good volume. I don't listen to music that way, so I'm more interested in how it sounds through a headset or plugged into external speakers. Hopefully it's better than the Beats on my Rezound.