I've read all the manuals, and the only thing that I can muster is that the audio line out port on the back of my Mac Pro "can be connected to powered speakers". So I connect it to powered speakers, and nothing happens. Is there some setting somewhere that I am missing? I've connected it to the front headphone jack and got sound from the speakers. But I'd prefer to keep the cables at the back out of sight, hence wanting to use the line out port. The same speakers work fine with line level inputs from a Minidisc player, so I'm just wondering if the sound card has a dead port on the back.