原帖由： rdklinc ,
I almost wonder if you speakers are blown, and you're hearing distortion. Do you have another topcase to test with? This may not be relevant, but I've had machines make a sort of popping sound upon bootup that only happens once, and then the sound works fine until you reboot, and that sound occurs once again. It's almost as if the sound is being "turned on", and you're hearing the speakers pop when that happens. In this situation, usually I have found that the sound is all the way up, and if you turn it down to 80% or so, that popping can go away. It sounds like your situation may be a bit different, but I thought I'd through that out there.