[MillDaKill]

1. How does PLII tell what sounds to put in the front and in the back from a stereo signal in the Music and Movie modes.





2. The nintendo gamecube has special PLII capabilites, when you start the games that support it you get a PLII splash screen even. does that mean that there is a way to encode matieral in PLII, or is it just standard PL? I have never seen any other media that bosted PLII.




3. How many channels does PLII support?

 

[hwc]

There is no such thing as a Pro Logic or Pro Logic II recording. Those are brand names for two of the many decoders that decode Dolby Surround encoded recordings. That's why you will never see a DVD labeled "Dolby Pro Logic". They are labelled Dolby Surround.


Matrix decoders work by analyzing the phase and amplitude relationships of the two stereo channels. When the same signal appears in both front speakers, in phase, it goes to the center channel. When the same signal appears in both front speakers, out of phase, it goes to the surround channels. When a signal appears in just one front speaker, but not the other, it stays where it started.


Obviously, this is very simplified for pure sine waves. Actual recordings are very complex so this decoding is quite dynamic. Variations in how much the signals are moved around under particular circumstances and other steering tricks account for the differences in performance. For example, wide center width on DPLII tends to move less signal to the center channel, narrow center width tends to move more to the center, etc.


Pro Logic II produces somewhere in the gray area between 4 and 5 channels. The basic decoding produces front, right, center, and a mono surround channel. However, steering logic can provide some stereo separation for two surround channels -- depending on the source material, etc. But, fundamentally, Dolby Surround recordings are 4-channels (front, center, right, surround) matrix encoded into 2-channels.


If you have a 6.1 or 7.1 channel, a second matrix decoder (Cirrus Extra Surround, Dolby EX, DTS-ES matrix) works on the two surround channels from the DPLII decoder to derive a third center surround channel in much the same way that Dolby Pro Logic derives a front center channel from the two front channels.

 

[sfogg]

"There is no such thing as a Pro Logic or Pro Logic II recording."


Half right. There is no such thing as Pro Logic *en*coding but there is PLII encoding and has been for awhile but mostly on video games. Dolby just announced PLII encoding for broadcast TV.

http://dolby.com/press/nab/pa_pr_030...Iencoding.html


Shawn

 

[petermwilson]

Hi,

FOX is going tolove that.


Now they can broadcast quasi HD and quasi 5.1.


I'm not putting down DPLII or DTS neo 6, i think there excellent DSP modes in the right circumstances, (personal preferences). Let's not forget my personal latenite lifesaver DOLBYHEADPHONE.


I was watching the Masters all weekend in either 7ch or NEO6 in HD and i eel it added that little extra to the broadcast for me. (my cable doesn't do 5.1)


Peter m.

 

[sdurani]

Quote:

Originally posted by MillDaKill 1. How does PLII tell what sounds to put in the front and in the back from a stereo signal in the Music and Movie modes.

The simple version:


Information that is in phase and recorded equally loud in both channels is extracted from the original stereo signal and sent to the centre channel. Even if you were listening with just two speakers, this information would have imaged in the centre anyway.


Information that is recorded out of phase in both channels is extracted from the original stereo signal and steered to the surround channels. Using certain cues in the other channels, the surround content can be steered towards the left or right surround channel to create stereo surrounds.


After all that extraction, whatever information is still left from the original stereo signal is sent to the main left and right speakers.


And there you have it. The stereo spread is maintained up front; sounds that would have imaged in the centre are stabalized with the centre channel; information that is in the recording (not generated by the processor) is used to create ambience in the surrounds.
Quote:

2. The nintendo gamecube has special PLII capabilites, when you start the games that support it you get a PLII splash screen even. does that mean that there is a way to encode matieral in PLII, or is it just standard PL? I have never seen any other media that bosted PLII.

I think some game players have PL II encoders built in.
Quote:

3. How many channels does PLII support?

For the moment it's only 5 (the sub is used only for bass management purposes). Hopefully, some time in the future Dolby will add on surround-back channel capability (either one or two channels).


Best,

Sanjay

 

[hwc]

Quote:

Originally posted by sfogg "There is no such thing as a Pro Logic or Pro Logic II recording." Half right. There is no such thing as Pro Logic *en*coding but there is PLII encoding and has been for awhile but mostly on video games. Dolby just announced PLII encoding for broadcast TV.

Thanks for the correction. I had not seen that announcement.


Just what the consumer needs...MORE confusion about surround formats! I don't know what Dolby is thinking. With the rapidly advancing onslaught of digital TV, they should be putting all of their marketing dollars into Dolby Digital. It is, insane, IMO, to call Dolby Digtal 2.0 "Dolby Pro Logic II".

 

[hwc]

Quote:

Originally posted by petermwilson I was watching the Masters all weekend in either 7ch or NEO6 in HD and i eel it added that little extra to the broadcast for me. (my cable doesn't do 5.1)

I wouldn't use the Masters as an example. CBS didn't do much (if anything) with the surround mix. However, there are many examples of TV broadcasts that use Dolby Digital 5.1 and Dolby Surround to great effect, including many CBS shows such as many flavors of CSI.


I am confused though. How is it that you have a set-top box for HDTV that doesn't pass a Dolby Digital 5.1 signal over a digital cable to your receiver? I'm not aware of any HDTV cable boxes or HDTV tuners that don't have a digital audio output with a raw digital bitstream for decoding by the receiver.


Passing the Dolby Digital 5.1 signal from the network does require the local affiliate to upgrade their audio equipment. But, it seems that most stations are making that upgrade as part and parcel of their HDTV upgrades. I know that the Boston affiliates are passing a Dolby Digital 5.1 signal on their HDTV feeds.

 

[sfogg]

"to call Dolby Digtal 2.0 "Dolby Pro Logic II"."


It can definitly get confusing. In that case I assume DD2.0 is the carrier and what it is carrying is PLII encoded.


Shawn

 

[petermwilson]

Hi,

I would agree that programs such as CSI lend themselves more to DPLII or DTS neo6 than the Masters. It was kind of neat though to hear the cardinals's singing in my surround speakers and the announcers coming from the fronts.


My statement about my cable box was poorly phrased. It does provide 5.1 from ABC from time to time which is the only HD network i recieve that broadcasts some programs in 5.1.

It is hit and miss however, if my cable company decides to pass that along.


Generally the best i would recieve would be prologic, but i think the point is moot in that my reciever takes over the digital or analogue signal depending on the group of channels and incurs whatever dsp mode i choose for that particular program. i have both the analogue and digital outputs of the cable box connected to my reciever.


In other words unless it's dd5.1 that the cable company is passing thru i choose whatever sounds best to me based on the limitations of the rteciever. Actually i use 7 channel stereo quite a bit, patriculary for sports.


Peter m.

 

[hwc]

Quote:

Originally posted by petermwilson Hi, I would agree that programs such as CSI lend themselves more to DPLII or DTS neo6 than the Masters. It was kind of neat though to hear the cardinals's singing in my surround speakers and the announcers coming from the fronts.

Ha! The birds chirping during the Masters telecast freaked my cat out. He started stalking around the den in "high alert" attack mode!

 

[cwood]

Quote:

Originally posted by sfogg "to call Dolby Digtal 2.0 "Dolby Pro Logic II"." It can definitly get confusing. In that case I assume DD2.0 is the carrier and what it is carrying is PLII encoded. Shawn

Dolby 2.0 can be stereo only or it can be encoded. Either way PL 2, L7 or Neo 6 will function with it.


C Wood

Fosgate Audionics

 

[petermwilson]

HWC,

It was something like that which caused my cat to attack a wall mounted surround speaker recently which cost me $250cdn for a new woofer after it bounced off a bookcase and then a table..


If i could have gotten it on film i would have tried to sell it as a "speaker ad" to the Totem company.


But i love my cats,


Peter m.

 

[hwc]

Quote:

Originally posted by cwood Dolby 2.0 can be stereo only or it can be encoded. Either way PL 2, L7 or Neo 6 will function with it.

It can also be the downmixed stereo output from a Dolby Digital 5.1 soundtrack. If the 5.1 soundtrack is matered properly, with the surround channels 90 degrees out of phase, the downmixed 2-channel output should be decoded properly by a Pro Logic or Pro Logic II decoder. In the case, the downmix feature of the Dolby Digital decoder is actually serving as the Dolby Surround encoder.

 

[SevenVII]

Quote:

It was something like that which caused my cat to attack a wall mounted surround speaker recently which cost me $250cdn for a new woofer after it bounced off a bookcase and then a table..

Yeah, on the scene where the kids have to pull the mandrake root plants out of the pot in Harry Potter:Chamer of Secrets... my cat made a mad dash towards the front bookshelfs. She paused long enough to alert me to the fact she was getting ready to attack. She was in crouching position right as I got to her and prevented the onslaught to my grill.


I am really worried though when I get the SV sub....it resembles too much the mother of all scratching posts......

 

[petermwilson]

Hi,

This is my last cat thing.

I have those Totem Acoustic Beakes. They look like lage silver suppositories and sit ontop of my fronts which are on stands. They only weigh about 2oz each and i'm constantly having to fish them out from under the couch.


Peter m.