I got a set top satellite receiver with both CVI and AV outputs, as well as a coax output. My xbox 360 has CVI and AV outputs, and my TV is an RCA with one coax input, one cvi input, one av input, one side av input and one av output. I am trying to get both the xbox and the set top box run at the same time. I tried a female to female coax, but the picture was grainy. So I've been trying to CVI the xbox with two ports from av for sound, while at the same time AVing the set top box. For some reason though, I cannot get the sound to work properly, such that both speakers work on either CVI or AV modes. Help?