Hi! I want to help my father hooking up a set of 5.1 speakers to his iMac. The speakers have these 3 plugs Orange, Lime and Black. Model: This is the iMac model This is the back of the iMac. I assume I need some sort of adapter, but didn't find anything where I could plug those 3 plugs into. - Any products you would recommend? Regards, DMTWorld.