For some reason, I was under the impression that surround sound could only be transmitted using HDMI or SPDIF. I've got my cable box hooked up to my sound system with regular RCA cables today, and it sure sounds like the DD5.1 is working. Is that possible?

For some reason, I was under the impression that surround sound could only be transmitted using HDMI or SPDIF. I've got my cable box hooked up to my sound system with regular RCA cables today, and it sure sounds like the DD5.1 is working. Is that possible?
If your cable box is connected via it's R+L analog outputs, then no, you are not getting DD5.1. Most likely your receiver is applying Dolby Pro Logic II (or other DSP) to the 2-channel source.

If it has the capability, and you have connected your cable box via its digital coax output (which is a type of SPDIF), using a single RCA cable, then yes, you can transmit DD5.1 via a digital coax cable connection.

Okay, so the surround sound I was hearing was basically simulated. Thanks, that's pretty-much what I though.