Dolby 5.1 versus 2 ch surround sound

I just got a DVD player, which I hooked up to my Dolby Pro Logic receiver with the ordinary L and R connections (composite audio). When I play DVDs, they often have the option of “Dolby 5.1” or “Dolby 2 ch” audio. Which should I use? I checked the Dolby web site, and several pages of surround sound explanations, and I understand that 5.1 actually uses six channels and is wonderful if your receiver has a digital decoder yada yada, but when I use this track (sometimes the only option on the DVD) I seem to get good sound. Likewise “2 ch” works fine. (The main difference is that 2 ch is louder than 5.1.) So, is there a difference, and if so, what is it?

Dolby 5.1 is designed for 6 speakers, whereas Dolby 2ch is designed for 2 speakers, which you have. That said, your DVD player is smart enough to know that if you pick 5.1 and only have 2 speakers, it will downmix to 2 channels.

Stll, I would go with the 2ch track, as that accurately reflects your system. I’ve had some trouble playing the 5.1 track trough my 2 channel system with some DVDs (Tora Tora Tora comes to mind).

Also, your Pro Logic system will probably work better with 2 channel audio. Pro Logic is an older surround sound scheme that “faked” suround sound from a normal stereo (2 channel) signal.

Ooops, forgot to mention my speakers. Pro logic, as I understand it, takes a two-channel input and decodes it into four channels: left, right, center, and rear. I have all the speakers connected (two for the rear channel, so 5 speakers in all).

Anyway, racekarl, you seem to be saying that 2 ch is what my Pro Logic receiver expects, but 5.1 will be converted into a Pro-Logic type output that my receiver will be able to decode. Have I got it right?

If you do not have a digital connection between the player and the receiver, you will get best results from using the 2-channel setup. If your player has either optical or digital coax outputs and your receiver has an input that corresponds, you can purchase a cable at Radio Shack that will allow you to use the Dolby Digital connection.

Hope this helps.

Yes FriendBob, thats right. I usually never mess with the audio settings on DVDs, as my DVD player is able to find the right track.

Your DVD player will almost certainly be able to send 2ch stereo to your receiver regardless of what menu option you choose on the DVD.

What I am not sure of is whether you will get the benefits of the Pro Logic surround.

So 99% of the time you can just play the DVD without having to choose. If you have trouble, or have to choose anyway, choose the 2 channel track.