singing lasers?

I was watching my nephew a wile ago and he wanted to watch a dvd called "Animusic", it is a searies of music driven CG videos. One thing in the show realy intreaged me, it had lasers being used as an instrament. So I ponderd if some one playing with powerfull lasers has ever noticed a poping sound coming from the laser heating the air it passis through, like a lightning bolt? If any one has noticed this, that means you could make a laser into a speeker by having the laser pulsate at a given frequincy.

Any ideas?

Don't put your ear too close to it !