Sorry for the late reply. When it comes to hooking up your Slingbox PRO-HD there are 2 places to connect your audio cables. If you're connecting your PRO-HD to your set top box using component cables (Red, Blue and Green) then you want to hook up a set of Red and White audio cables as well. You will hook all 5 cables up to the "output" of your set top box to the "input" (top row) of your Slingbox and then another set of the 5 cables from the "output" (bottom row) of your Slingbox to an "Input" on your TV. If you're connected this way, you want to make sure that your red and white audio cables are plugged into the ones that are the closest to the red, blue and green inputs. So on the back of your Slingbox PRO-HD you should see (starting on the far right hand side) a place for a red, green and blue cable. These are for your video. Then you will see a place for an orange cable and then a red and white. Hook your audio cables into the red and white and nothing into the orange.
Now if you're hooking your Slingbox up via composite cables, then you want to hook the red and white audio up to the far left of the Slingbox. So you will hook red, white and yellow from an "output" on your set top box to an "input" on your Slingbox (top row) and another set of red, white and yellow cables from the "output" of your Slingbox to an "input" on your TV.
If you need any further assistance, please feel free to respond to this post and again sorry for the delay!
Sling media Moderation Team