macbook pops when system audio turns on/off

dreeder's icon

Apologies if this is off-topic.

Macbook; OS X 10.5.8.

System audio generates a popping sound before and after sound events. This happens with anything, Max, iTunes, ... Perhaps when the audio system turns on/off?

I generate sound, after a minute or so it pops. Then again, when generating sound after a respite. I did not notice this on macbook with 10.4.*.

??

thx,
david