Thanks for the replies everyone. Since there are a few responses here, my main concern is that if you see other performance issues like lag or framerate drops, then the audio is directly tied to those. But if you are only hearing audio issues it will be a little bit trickier to debug what is going on.
For the sake of get as much info as possible, can you please tell me which champion you were playing, did it happen in team fights, or only when one or two other champions were around? only the Announcer, or was it Champion Voices as well? Did it occur as the start of the game, or only Late in the game? And any other detail you might feel are relavent....
Any additional info you can provide will go a long way in helping us get to the bottom of the problem.