Can someone else with a G5 check something for me? I have a set of speakers plugged into the speaker-jack in back of the computer (analog speakers). I was under the assumption that if I took a set of headphones and plugged them into the port on the front of the computer, the computer turn off the regular speakers and only send the signal to the headphones. That isn't happening...the sound plays through both the speakers AND the headphones. Is that what should be happening, or is something wrong with my computer?