Why not use DPL II to extract the EX rear Center channel? (1 Viewer)

[Roland Wandinger]

I have posted a similar thread some time ago but didn't get a lot of feedback then:
Since DPL II has better channel separation and is overall regarded as the best matrix to achieve surroundsound from 2 channel material why not use it to extract the rear center channel from 5.1 DD-EX and DTS-ES encoded soundtracks?
All THX-EX receivers and processors use plain old DPL to extract the rear channel. DPL has a tendency to collapse to mono which would also be avoided by using DPL II.

 

[Wes]

I posted the same tread months ago,I preformed a search and could not come up with that thread! Roger Dressler with Dolby stated that there would not be too much difference, I even asked if Dolby would take the PL II processing and up grade EX. But Roger said Dolby has no plans to do so. I personally feel it would make a difference, but would it be worth buying a receiver that has PL II to accomplish this?

Since DPL II has better channel separation and is overall regarded as the best matrix to achieve surroundsound from 2 channel material why not use it to extract the rear center channel from 5.1 DD-EX and DTS-ES encoded soundtracks?

Now remember you would not be using the so called "Matrixed" (out of phase surround) part of the PL II processing. The front stage (EX Surrounds in this case)is merely creating a center channel out of Inphase mono info shared by the Right and Left channels. Jim Fosgate does claim however that PL II has improved the front stage as well as split/stereo full range surrounds.
Wes
[Edited last by Wes on October 04, 2001 at 05:39 AM]

 

[Roland Wandinger]

Now remember you would not be using the so called "Matrixed" (out of phase surround) part of the PL II processing.

Actually I'm using the "out of phase" signal in the EX processing! The stereo sourroundsignal form my DD/DTS decoder goes thru an ordinary DPL decoder where it gets PL processing, I send the "out of phase signal" to two speakers which I have placed in the top-back corners of my HT.
The result is a vastly expanded surround stage, you are getting the feeling that your room has doubled its size.
Some might say (and have said) that this processing is just a gimmick like some DSP programs and alters the sound mix.
I for one were very impressed with the result I got, so much that I watch basically all 5.1 DD and DTS movies with this processing engaged.
Now I'm dying to hear how this would sound with the fullrange-stereo processing DPL II provides for the "out of phase" signal?

 

[Jerome Grate]

It works with logic 7. I've tried it and it works, but you have to really calibrate for it. I tried it with Independence Day (VHS) and other active surround movies as well as active t.v. shows. The one I found to very active is Invader Zim on Nickelodeon and you there is clearly a rear center channel and stereo surrounds. This of course is with a Psuedo EX set up.
------------------
If loving Home Theater is
wrong, I don't want to be
right!!!

 

[Roland Wandinger]

Hi Jerome
I'm not sure we are talking about the same thing? I'm not suggesting to distract a Center-back channel from the stereo surroundsignal generated by DPL II (or in your case by Logic 7) from a 2 channel stereo soundtrack (although you seem to have achieved this).
What I'm suggesting is to use DPL II (or even Logic 7) to extract the center-back channel (and even the two "out of phase signal" channels like I use) from the two surround channels of DTS-ES and DD-EX encoded 5.1 soundtracks.

 

[Jerome Grate]

I get what your saying, now, I guess it would depend on the receiver I believe. My HK won't allow me to apply Logic 7 to DD/DTS 5.1 material I think the same holds for DPL II.
------------------
If loving Home Theater is
wrong, I don't want to be
right!!!

 

[Wes]

Actually I'm using the "out of phase" signal in the EX processing! The stereo sourroundsignal form my DD/DTS decoder goes thru an ordinary DPL decoder where it gets PL processing, I send the "out of phase signal" to two speakers which I have placed in the top-back corners of my HT.

If this is in fact what you are doing then it can not be considered EX! EX is inphase mono info that is shared by the surround L/R channels. You would get a better sounding full range EX effect with the correct set up. Have you tried the PL front stage for your DIY EX set up?
Wes

 

[Kevin C Brown]

Wes- I took Roland's comment about using the out-of-phase signal from the DPL processor in the rear to mean that he had *2 extra* speakers back there.
In other words, normal "front" DPL processing for the rear center(s), and then the out-of-phase "rear" DPL processing for 2 extra speakers in the "top back corners" of the room.
Roland? If you *are* only using the out-of-phase signals (the "rears" from the DPL processor), I can't imagine that that would sound any good.
Got to be careful in that all the way around, the "back" becomes the "front" when your doing homebrew THX EX!
------------------

 

[Shade Watson]

Roland,
I think the simple answer is that DPL does a good job creating the front three speakers when the source is properly encoded. DD EX and DTS ES Matrix are properly encoded and work great with DPL processing.
I think DPLII would work a lot better extracting the center rear channel than DPL does from 5.1 sources. The reason that Dolby doesn't feel the need to update DD EX is because the format is not meant to extract a center rear channel from the 5.1 sources.
If you are making a home made 6.1 system using a separate processor to extract the center rear, DPLII would be the way to go when using 5.1 sources. I think you would find very little difference with 6.1 sources.