Dolby Pro Logic IIx

[jsteinhauer]

If you have lossless 5.1 sound going from your BD player to your receiver, and you want to take advantage of your rear surround speakers, will applying Pro Logic IIx retain the lossless 5.1 part and generate a rear speaker signal, or will it degrade the sound coming out of the fronts and sides?

[Zaphod]

I believe it is one or the other...lossless or Pro Logic IIx with Dolby Digital being the format that is used for the 7.1 channels.

[MouseRider]

First of all, what DPL IIx does is take a stereo matrixed soundtrack and make it 5.1/7.1, so what you're talking about here won't work.

I think what you're thinking of is the kludge in the early days of 6.1 (Dolby Digital EX/DTS:ES) days where people were taking DPL processors to decode the matrixed rear mono-surround soundtrack that is embedded into the two side channels.

Today, there are many receivers and processors that have systems that will expand a 5.1 source to 7.1 by using various sound steering techniques.

Then when you say "degrade", it depends on what you mean by "degrade".

When you apply any type of post-processing to sound, it changes it.

[jsteinhauer]

What I undstand happens is a Dolby track contains a certain flag that enables a rear signal to be "created". I have no clue how it works and what types of encoded or unencoded sound tracks would be thus flagged. I have have not been able to clarify myself whether this changes any of the 5.1 outputs in the "creation" of the rear outputs. Understandably, Dolby suggests it is most useful for Dolby Digital tracks. It is really only a matter of curiosity. When you have rear surrounds, you would like to be able to use them all of the time, instead of just some of the time.

[MouseRider]

What you're talking about is probably Dolby Digital EX. EX-encoded soundtracks have a mono-rear surround track encoded into the two side tracks. There is an EX flag in Dolby Digital tracks.

If your receiver supports Dolby Digital EX, THX Surround EX or similar, it will decode that information and send it to your rear channels, it will not change the original 5.1 information.

Whether you can use the rear surrounds all the time depends on what you watch, your receiver/processor and what mode you use.

I have a 7.3 system and I use a processing algorithm known as Logic7 or EX/ES modes when the content supports, my rear channels are always in use during movies.