Prologic 5.1 Versus All (Natural) Channel 5.1 Please Explain

[EdwardGein]

Would welcome someones clarification here on what exactly prologic is & its use in relation to 5.1 systems & 5.1 TV Broadcasts and 5.1 DVD's. Specifically, for this post only assume you are playing only a 5.1 DVD or listening to a 5.1 digital TV broadcast not a 2 channel stereo broadcast or DVD/CD.

1. Should DVD's be listened to on the all Natural 5.1 mode on your receiver or should they be listened to in the Pro Logic mode? Which gives better sound? Does the Prologic Mode change the way the sound was originally suppose to be heard in 5.1 all natural in regards to DVDs and TV broadcasts?

2. Same thing on TV. Which sounds better Prologic 5.1 or Natural 5.1 Is the Prologic a distortion of the original sound? I have to admit I heard a TV broadcast in Prologic at someone on this forums system & it sounded great but I'm continuing to listen to TV in the all nastural 5.1 mode because I think Prologic changes the way the 5.1 audio was intended but I could be totally wrong & I'd like to know if I am. Thanks for any answers.

[kexodusc]

With a 5.1 source, Pro Logic shouldn't even be an option. Dolby Digital takes over.
5 channel stereo, and other DSP's that use 5-channels are just a receiver's best guess as to what would sound good coming out of 5 speakers. It isn't "natural" at all.
If you get a 5.1 signal, use Dolby Digital or DTS, or Pro Logic IIx or something newer.

[EdwardGein]

With a 5.1 source, Pro Logic shouldn't even be an option. Dolby Digital takes over.
5 channel stereo, and other DSP's that use 5-channels are just a receiver's best guess as to what would sound good coming out of 5 speakers. It isn't "natural" at all.
If you get a 5.1 signal, use Dolby Digital or DTS, or Pro Logic IIx or something newer.

On the Denons, doesn't 5.1 dolby digital take over automatically?

[N. Abstentia]

On the Denons, doesn't 5.1 dolby digital take over automatically?

If you send it a Dolby 5.1 signal then yes it should.

[kexodusc]

Not sure why my reply is up so high...
PL II actually works with 5.1 too, keeps the channels discrete, but matrixes the back channels. I haven't seen anything suggesting it's done any different than the EX option that does the same, but now I wonder...

[EdwardGein]

I'm still a ittle confused what you guys are saying, keeping in mind, I'm only talking about 5.1 DVD's & 5.1 TV broadcasts. Starting with DVD's, the Denons will automatically revert to 5.1 dolby digital unless you put them in DTS. On TV, if its a 5.1 broadcast, to me this means that on the all channel setting it will send the signals to the correct channels & sub as opposed to the Pro Logic which will alter the 5.1 signal. So why should I change from the natural 5.1 setting to the Pro Logic setting for a 5.1 broadcast?

[kexodusc]

On every receiver I've used that can auto-sense the signal, yeah...it takes over. Pro Logic turns 2-channel stereo into a surround sound using information encoded on each of the two stereo channels. Dolby Digital and DTS received 5 dedicated channels not shared with any other.
Pro Logic is okay for TV or old VHS tapes, but for DVD, you shouldn't be using.

Pro Logic II takes these a step further...turns 2-channels into 5, 6 or 7 and sounds much, much more realistic, and better than Pro Logic. It can be used with Dolby Digital and DTS as well to get 6.1 or "7.1" sound. Most decoders also have an EX/ES option on them that adds the 6th and 7th channels as well. I can't hear any benefit to using Pro-Logic II over these if a source is 5.1.

[N. Abstentia]

Yep, listen to Kex.

I'll just add....Dolby ProLogic is not 5.1 at all. Not even close. Dolby Pro Logic II is 2 channel, with matrixed surround and center...which means it takes the 2 channel signal and like Kex said...takes a guess at what the center and surrounds should do. For regular TV I do like Pro Logic II, it works quite well. It's just the opposite of 'natural' which is not a big deal for TV. But for 2 channel music, I don't want to extra artificial stuff in my 2 channel.