You may not hear a sound but see the music one is actually listening to. For the music can be heard by the head bopping or knocking which is going on. Smooth sounds usually produce a slow methodical strumming of one’s head while heavy metal produces one that pounds out the notes. In between the clarity might not be as obvious to the untrained eye and everyone has a distinct style but once you careful review the sights then then sound behind is heard as well. In the end you might want to hide what you’re listening to but it will become crystal clear once we look at the notes that your head glides to.