I am planning on purchasing the 27 inch iMac. Right now I am able to output video and audio to my a/v reciever and then to my large tv in the next room so I view content. I own a windows computer now with external speakers and I simply split the audio signal so I can listen to audio simultaneously at computer and through a/v receiver. My question is since the speakers are internal on the iMac, do they get muted if you plug in a audio connector into the audio output jack.