I got an iMac 27" I have another 23" BenQ monitor I want to hook up as 2nd monitor and as well as a partial PS3 output. That monitor has HDMI and will take the PS3 audio and output in it's headphone output. I have a line which connects the BenQ's headphone output and into the iMac's line-in. I changed the audio setting from the mic to the line-in. I see the blue meter go up when I know there is sound from my PS3 but I don't hear anything on my iMac's headphone. How do I make any audio direction enter into the line-in and directly out to my headphone or is that no possible?