My current setup(pictured below) is that I have my rMBP and my PS4 connected to my TV. I dual screen the rMBP, but both the rMBP and PS4 use the TV speakers for sound (when one or the other is in use). What I was considering doing was getting some external speakers, but figured I would need a some sort of device that could accept two sources (digital and analog) and connect them to speakers. Am I even in the right ballpark with what I am looking for? If so, or if not, what should I be looking at? Thanks in advance.