I work at a school and am looking for a device that will split the HDMI video and audio coming from our Apple TVs to send the video over HDMI to the HDMI port on the wall plate, and then up to the projector, and split the audio off into either RCA (preferable) or 3.5mm audio so I can hook that to the wall plate and send it to the sound systems. Something around $20-$30 would be most preferable. The teachers' computers already use the 3.5mm jack on the wall plate, but they can either learn to switch them out, or maybe I could use a splitter to send 2 inputs in? Just looking for some advice and product recommendations. Thanks in advance.