No, not that. It can be ANY type of sound. Say, for example; I'm playing a game and data is being read off of the CD drive... Well, the sound distorts in synchronisation with the CD drive read-light. It will happen outside of games too (on everything), for example; I could be listening to an online radio stream, and if I'm transferring data from my CD drive, whether it be data files or the like, the sound will distort in synchronisation with the CD drive read-light.
I'm wondering whether or not it may be that my secondary IDE channel is on a transfer-type that the drive doesn't necessarily agree with, yet will use if it has to. The current transfer mode is PIO Only.