Macbook to TV - No Sound

I have the 13" Black Macbook set up to go to my 32" Samsung. I was able to connect it fine to the TV through an HDMI cable however I am unable to get any sound through the TV. Instead the sound is coming from the MacBook. Now I bought a 3.5mm Stereo Plug/2 RCA Plug cable for the sound. I plug the 3.5mm into the headphone jack and the RCA cables into the TV, but no sound comes out. I am wondering if I got the wrong size cables. And if anyone know what the cause could be? When I plug the Xbox or the DVD player into the TV I get sound from those systems. When I plug Headphones into the laptop I hear sound coming from the computer. I believe it is the cable which is the issue, but was hoping I was just missing a setting on the laptop maybe to set up the sound.

The problem likely is on the TV's end. Have you told the TV to look for the audio coming in through the analog port, and which port it would be? It may be set up to expect the audio over HDMI.

I had the same problem with a Sony TV. Will try that out and report back!

Thank you. The problem was I have two HDMI slots. I took what you said and tried the other HDMI slot and then plugged the RCA cables into the DVI audio in ports and the sound came in crystal. Thank you very much.