MacPro Quad 2.66 4gig...Tiger... Every once in a while it does this... I have my headphones and external monitors hooked up to the line out on the back, nothing plugged into the headphone jack on front. I usually have all sound going out the line out. Now for some reason I have audio like music, video, etc coming out the internal speaker and my sound effects coming out the line out. Adjusting volume only controls the line out. Can't adjust or mute the internal speaker. What gives? Ok...more specifically...only audio from safari is going out the internal speaker...everything else going out the line out.