Hello i am currently using a samsung Tv Mohls6187wxixaa it's a 62 inch, i'm currently using direct Tv and have a small direct tv hd receiver which is connected to the tv via hdmi, which is fine however i have an older set of coby surround sound theatre system speakers and subwoofer id like to use, the model is csp86, it's older and only has RCA hook ups, i would like to use the HDMI for Video only, and use my subwoofer + speakers for sound. Do i need a digital cable to RCA or an 3.5 mm to RCA cord to set this up? please help, thank you