OK I did a search and couldn't find the answer to this question. I am looking to help my brother get a system set up with a digital sound projector. He doesn't want to run wires all over the place so this seems like the best option. Couple of questions. Do you need a reciever with these or do they have a built in amp? If you want to add a sub do you then need a reciever or can you plug it into the sound projector? Finally any recommendations for which ones to get?