Surround Sound and Left/Right analog RCA connections

[charwell]

Hi forum readers/moderators:

I'm in a bit of an arguement here at work over surround sound (5.1, etc.).

The premise concerns a basic connection; imagine wiring your audio run from a DVD player to a 5.1 surround processor using just 2 unbalanced RCAs (one from the left line out and the other from the right line out on the DVD player), connected to the Left/Right RCA audio inputs on the 5.1 receiver.

My question is this: Is there any encoded surround information containing 5 separate channels of audio when you use the Left/Right analog RCA connections? Or are the rear surround and center speakers simply a duplication of the front left/right channels? Assume that the media is recorded with 5.1 encoded track, that the DVD player is 5.1 complient, as is the receiver.

Let's see what the world thinks.

Thanks.

 

[markw]

The premise concerns a basic connection; imagine wiring your audio run from a DVD player to a 5.1 surround processor using just 2 unbalanced RCAs (one from the left line out and the other from the right line out on the DVD player), connected to the Left/Right RCA audio inputs on the 5.1 receiver.

OK, you're running a two channel analog signal from the DVD player to the receiver. The best you will be able to get out of this is DPL or some other matrixed system. this "derives" additional channels from the two you sent it.

My question is this: Is there any encoded surround information containing 5 separate channels of audio when you use the Left/Right analog RCA connections? Or are the rear surround and center speakers simply a duplication of the front left/right channels? Assume that the media is recorded with 5.1 encoded track, that the DVD player is 5.1 complient, as is the receiver.

None of the above. There are only two separate channels. The rears are not merely duplicates of the fronts. The additional channels (aside from the front R/L) are mathematically derived from the original two. IOW, they don't exist in the real world. FWIW, this works wonders on VHS HiFi tapes.

If you want the five (or six) separate channels (plus a LFE) you need to feed a digital signal (via either a digital coax feed or toslink) from the player to a receiver capable of decoding these, usiing either Dolby digital or DTS. Ain't no way to get these via those through that red/white analog connection.

 

[j_garcia]

Dolby Surround is what you can get with a stereo analog connection - some material that is encoded with Dolby Surround or ProLogic2, will play back in 5.1 channels, but the sound is not true surround, it is matrixed as MarkW mentioned - the center and surrounds ARE encoded into the stereo signal, but they are bandwidth limited and they are not discrete. Regular stereo material may or may not give you a good surround effect, as the ProLogic data is not present.

You can get true, discrete surround either via digital as mentioned OR via a DVD player that has 6ch analog output and built in decoding connected to a receiver that has a 6ch analog input.