The only way I can describe this
effect is the
earthquake effect.
Usually found in
Limp Bizkit and
Korn videos and the like, although it has been seen in some
Hip-Hop videos too. The group start jumping up and down or stamping their feet, while at the same time the camera shakes violently. This
visual effect gives you the impression that the
music is literally
tearing the house down. Adding this effect can make the music sound '
harder' than it really is, but it's just your brain associating the
violent shaking with the
music.