AVS Forum banner

1 - 6 of 6 Posts

·
Banned
Joined
·
5,125 Posts
Discussion Starter #1
Ever wondered where some of the end credits music and lyrics is coming from or even a few sound effects and the odd rare dialogue that has been sent to left and right with equal phase and frequency response, no?


Well here's your chance of rather basic and simple improvement thou not really an improvement merely an extension of blending the common centre phantom signal from left and right and blending it into the centre channel. The diagram is so basic its more or less on the same principles of the Dolby EX process that evolved from the Dolby CP45 cinema processor and was later modified into the Dolby SA10 for Star Wars episode 1: The Phantom Menace and Fight Club (1999).


If you use matching fronts and if you where to add a fourth into the front thou placed above the centre channel and select stereo mode to preamplifier you'll end up with pre Voice of God IMAX approach, thou the IMAX is six-track discrete left centre upper centre right with independent left and right surrounds. The sub bass is diverted from all channels to the 8 subs placed below the centre channel.


If Dolby where to get there act together it would be feasible to encode the original mix onto DVD only a new type of process or approach is needed to or the same principles of bass management to send the six channels to the sub bass. The upper centre would have to be sent to the LFE.1 channel as full spectrum channel and bingo you've got true IMAX six-track in the home, or IMAX 6.0.



Anyway follow the simple diagram along with calibration disc. Use the disc to set-up the LCR fronts or L/C/UC/R (UC = upper centre) depending on set-up and readily available loudspeakers amplifiers.




Once all is connected in the diagram turn off or mute surrounds and LFE.1 sub bass, play (wideband full spectrum pink noise all channels) and re calibrate levels of the main LCR as the Dolby stereo pro-logic decoder will be acting like preamplifier set the levels to match the centre channel that is, you set the levels to the same level as before 75db LCR or what ever you prefer.


Now mute left and right fronts along with the centre channel that is outputting from the main Dolby dts decoder AVR. You can now turn on the Dolby stereo pro-logic decoder while playing (wideband full spectrum pink noise all channels) and monitor the centre phantom signal on the centre channel in the room, and set the level on the Dolby stereo pro-logic decoder via its own level to equal SPL db 75db or what you prefer, just as long as the levels are set to the same SPL db.


Now play some movie program. You can bypass the Dolby stereo pro-logic mode anytime you wish; this will not degrade the soundtrack unless you follow the diagram and instructions.


If you wish you can install EQ between the outputs from Dolby stereo pro-logic decoder and the main centre channel output if you have tone frequency differences and chances are each and everyone of us have few db more on the HF left centre or right and little trim will bring it all into focus, providing the LCR are at the same height level and aiming downwards to the sweet spot.


I'll add the next chapter to this later on.
 

·
Banned
Joined
·
5,125 Posts
Discussion Starter #4
Anyone interested in trying the five-screen experiment? Then hare it is a simple diagram as the original one no longer exists on the main page due to the URL link gone missing? So I've looked over the original and just applied my own, hope its easy to follow and it does require several Dolby stereo Pro-Logic decoders amplifiers and more importantly matching five sets of loudspeakers, preferably JBL.


The original article written by Norm Schneider is quite ingenious and it really does work.



Quote:
Originally Posted by JBLsound4645 /forum/post/14240289



The Search For New Channels
Reproducing SDDS Soundtracks
Norm Schneider


Real Channels


It is interesting that many manufacturers of home theatre processors have derived additional playback channels that are really not there. By adding circuitry to pull infor*mation from sounds that momentarily travel from the screen channels to the surround channels, additional "fill‑in" material can be directed to side wall loudspeakers to give the illusion that the sound is moving from the screen, down one wall, to the left or right surround loudspeaker(s). Since home equipment is designed and built for the pleasure and satisfaction of the buyer, there is nothing wrong with this technology. In professional movie theatres, we cannot get away with these schemes because the movie producer is looking for as accurate a playback as possible. This scheme is simi*lar to the Surround EXT" format where an additional sound channel is matrix encoded between the left and right surround channel on Dolby Digital or DTS Digital Surround soundtracks. The difference is that the cen*ter surround channel is a separate and dis*crete (real) channel added to the digital soundtrack.


There are, however, two real additional channels on many digital sound DVD discs that have gone unnoticed by these same manufacturers. Perhaps they have not dis*covered them or do not feel they add that much to the presentation. Before I tell you where they are and how you can retrieve them, let's talk about how some of the major digital soundtracks are prepared for theatri*cal release.



The Printmaster


The 5.1 digital sound on your DVD comes from the same printmaster used by the movie companies to encode their sound*track into each of the three digital format processes commonly used in professional cinemas. The tracks are encoded into their proprietary format by each company and released to the theatres to play back on their own brand of processors, There is no compatibility between the three professional systems, and none are c compatible with the home versions of their own systems. Dolby and DTS have higher bit rates on their home systems than the professional version so a separate encoding process is required for the DVD digital release from the original stu*dio master recording. The encoded sound printmaster used in the production of a the*atrical film cannot be moved to the home DVD release because of these compatibility issues.

Sony Dynamic Digital Sound SDDS


The one system that has no counterpart in home systems is the SDDS digital sound*track. It can carry eight full‑range channels, or nine when the center surround channel is added using analog matrix encoding and decoding. Sony SIDDS eight‑channel sound*tracks have been used in over 100 major movies, including a special mix for Star Wars: Episode I‑The Phantom Menace. A discography of the eight‑channel digital releases can be found on the Widescreen Review subscriber Web site at www.WidescreenReview.com .


Two additional channels are encoded as discrete channels for playback in motion picture theatres that are equipped with the SIDDS digital system. These separate sound channels are especially needed where there are very wide screens to avoid the holes between channels present in systems that have only three stage (screen) channels. The two additional channels are between the left loudspeaker and center, and the right loudspeaker and center. A totally panoramic stereo field is created with sepa*rate material on each of the five channels. Aseparate eight‑channel master is delivered by the studio to the SDDS folks for encod*ing into their process. The 4tudio may deliv*er a mix‑down master to the 5.1 format for use in the Dolby and DTS formats. An eight-*channel master may be sent to the DVD authoring contractor for additional post pro*duction processing by those companies, or the 5.1 mixdown already contains the extra sound material.


When the eight channels are encoded into 5.1 format what happens to the two additional channels? Do they throw them away? No way! The extra channels contain separate material, such as certain instru*ments from the orchestra, sound effects or even dialogue. The additional tracks are commonly spread equally between the left and center channels, and the right and cen*ter channels so that nothing is missing in the playback.


What about cinemas that use the Sony SIDDS digital system that do not have five playback loudspeaker channels on stage? The Sony processor can be programmed to do an internal mix of the extra tracks. This is done during the initial setup of the equip*ment so that the two extra channels are divided one‑third to the center, and two‑third to each of the outside channels. The theatre can use their system in a 5.1 mode without losing any of the original recording.


The use of five full‑range stage channels is not new. The original Todd‑AO magnetic 70mm soundtracks have five full‑range stage channels and one surround channel. It was common practice during the 50's and 60's to also include dialogue on the extra channels. If an actor moved from the center of the screen to full left, while talking, the sound would pass from the center loud*speaker to the left extra, to the left. That is rarely done today. Dialogue is "nailed" to the center channel no matter where the actor is standing in the picture. One reason for adopting a hard center dialogue channel is that cinema systems were not equalized 40 years ago and the characteristics of the voice could change as the actor moved between channels. Also the traveling voice was more difficult to reproduce in auditoriums with less than ideal acoustics. In great movies like Oklahoma, South Pacific, and others, do they throw away these channels in the DVD mix? Not at all! They are simply spread into the lesser 5.1 format stage channels. It is common for old timers to brag about how great the original Todd‑AO format was in movie theatres and wish it would come back. If these channels are really there, how can you retrieve them to play in your home theatre system?

How To Retrieve The SDDS Soundtrack


Several months ago we conducted experiments in our listening room at SMART Theatre Systems using a DTS professional cinema digital processor and the soundtrack of Godzilla originally recorded in the SDDS eight‑channel format. The analog outputs of the 5.1 processor were connected to two of the SMART' CS‑3X Jr. home theatre decoders. One between the center and right channels, and the other between the center and left screen channels. The listeners were completely amazed! Separate and distinct material was coming from the additional loudspeakers that were not duplicated on the main channels. The soundfield was totally panoramic with no gaps between the channels. (Please keep in mind that the outputs of the digital processor are analog, not digital.) At this point, a matrix steering device can detect common "in‑phase" material and direct it to a separate amplifier and loudspeaker.


We next previewed a DTS DVD of The Shadow, which was not recorded in eight-channels. The common mode material was again steered to our extra channels providing a bigger, more panoramic soundfield. Sounds that are panned from one channel to another will also appear momentarily in the new channels as the sound moves across the stage. Other movies also had pleasant surprises. Previously hidden material appeared on our new LE (left extra) and RE (right extra) channels. The sound coincides exactly with the action on the screen. Even though the early Todd‑AO 70mm soundtracks used the five full‑range stage channels, we cannot be sure the DVD author placed the tracks in the same place during mixdown to 5.1 digital. However, it should be fun to go through your library of DVD movies and see how many contain the extra "phantom" channels‑between‑channels.


Obviously we used our own CS‑3X Jr. matrix decoders that employ the patented Circle Surround *process. This product is very similar to the model we manufacture for movie theatres and is marketed to home theatre customers to produce the center surround channel in their playback system. It is, in fact, a full 5.1 analog matrix decoder and is ideal for decoding the PCM LT (left total) and RT (right total) outputs of your DVD player (for those of you who do not have a digital decoder). Another fine matrix decoder using Circle Surround is manufactured by Parasound. We do not believe you will get satisfactory results using products that incorporate a Dolby Pro Logic8 matrix decoder due to the well‑known and widely published quirks of that type of system. Since this experiment is all for fun anyway, you may want to play with various matrix decoders to hear the results.

It Takes TWO To Tango!



You must have two matrix decoder boxes that can be connected to your digital sound decoder. The first matrix is connected to the outputs of the left and center channels of your digital decoder or processor. This will produce a NEW left extra channel when material is present on the soundtrack. The matrix box has two inputs, but multiple outputs. The labeling may be confusing on the CS‑3X Jr. because the product is marketed to extract a center surround channel. Really, it is a high‑quality matrix decoder that may be used for several applications. Please refer to the wiring diagram for connection ideas.


If you wish to experiment with inexpensive matrix decoders, you will soon discover that you wind up with two center channel outputs, one from each box. (Pick either one to feed the center channel in your system; they are the same material.)


Now that the "cat is out of the bag," you may see future home theatre processors that can retrieve the extra channels. But for now a simple matrix decoder will give you the same thrill. This could be of some benefit if you have a large screen in your home theatre, or you are sitting close to the screen and can hear the "holes" in the 5.1 playback.


If you enjoy experimenting, play some of the original Todd‑AO movies (Around The World In 80 Days, Sound Of Music, Mad, Mad, Mad World), all the Cinerama movies, and many other early 70mm titles. The practice of using five full‑range stage channels was stopped in the late 1970s when the left extra and right extra channels were used only to add extra bass to the sound presentation. Since it is possible to modulate a magnetic channel to only 100 percent, you need to add more bass‑only channels to get more acoustic bass in the room during loud sound passages. This technique was affectionately called "Baby Boom." The digital soundtracks of today have a separate low frequency effects subwoofer channel to supplement the bass.


DVD's that were mixed from an eight-channel source will definitely contain the extra sound channels. Can you count on the mixer of the DVD digital soundtrack to put the additional channels equally between the left and center or right and center channels? Not always, but it is fun to find these little "gems" in many commercially released DVD's. If you are a home theatre experimenter, this could be a lot of fun. Big hint‑U‑571.


Norm Schneider is President of SMART Theatre Systems.


Circle Surround is a registered trademark of SRS Labs, Santa Ana, California.


Pro Logic and Surround EX are trademarks of Dolby Laboratories, San Francisco, California.


Reprinted with permission from WIDESCREEN REVIEW Magazine - ISSUE 59













Dialogue spoken in My Fair Lady (1964-1994) has Mrs. Pearce and Pickering voices heard more or less in-between left and centre while Higgins voice I walk over everybody is heard in the centre front, at present with the current set-up.


With the camera moving from different positions the continuity of sound and image is nicely placed






Here are a few that I have collected on the DVD and laserdisc format


1 The King and I (1956) DVD

2 Forbidden Planet (1956) DVD

3 South Pacific (1958) DVD

4 Spartacus (1960) DVD

5 West Side Story (1961) laserdisc DVD

6 Lawrence of Arabia (1962) DVD

7 My Fair Lady DVD (1964)

8 Doctor Zhivago DVD

9 The Sound of Music (1965) DVD

10 2001: A Space Odyssey (1968) laserdisc and DVD

11 Ice Station Zebra (1968) DVD

12 The Towering Inferno (1974) DVD

13 The Spy Who Loved Me (1977) DVD remixed for DVD

14 Close Encounters of the Third Kind (1977) laserdisc DVD

15 Superman the movie (1978) first edition VHS PAL transferred to DVD-RW

16 Alien (1979) laserdisc DVD

17 Indiana Jones and the Temple of Doom (1984) laserdisc DVD

18 Willow (1988) DVD

19 Indiana Jones and the Last Crusade (1989) laserdisc DVD

20 The Abyss (1989) DVD

21 Star Trek V: The Final Frontier (1989)

22 Terminator 2: Judgment Day (1991) laserdisc DVD

23 Backdraft 1991DVD

24 Hook (1991) DVD

25 Toy Story (1995) laserdisc

26 Mission to Mars (2000) DVD

27 Monster's Inc (2001) DVD

28 Flight Plan (2005) DVD
 

·
Banned
Joined
·
5,125 Posts
Discussion Starter #5
It's quite feasible to toy around with primary five channels once you know how they work or interact with each other and what you can achieve for your own home entertainment use only, something with different twist something that is going wow you or your friends.


Providing the surrounds are stereo otherwise it's not going to be quite affective if the surrounds are monaural (mono) you might be able to get shift or repositioning of certain sounds but they will only be moving from rear back to sidewall or centre wall surround. Yes I just make up these new names until someone patents it. LOL


It may sound complex, in fact it's almost over my head with the concept of the design but I'm certain the idea is sound, and will work, but like all new or untried concepts it's all trail and error and playful experimentation. The idea came to me several years ago and as still remained undone in practice.


Place the same Dolby stereo pro-logic decoders on each side with left front passing into the decoders right input and with right output feeding back into the amplifier for normal operation or special event DVD titles.


The right rear surround place the input into the left channel input with output feeding back into the amplifier to drive the rear or sidewall combinations attached to the sidewalls.


The centre channel output from the Dolby stereo pro-logic decoder feed it off to in one of two ways.


1 is to place a dedicated matched sidewall surround as seen in the basic diagram and send it directly to the middle.


2 is to keep all the sidewall surrounds playing the same signal but with near independent amplifiers driving the each sidewall arrays and with an audio mixer assigned to do a few simple mixing techniques of running the sidewall surrounds and several mixers will be needed you can blend the centre phantom signal once the decoder detects a signal that has near to the same frequency response it will be divided, subtracted from part of the left front and rear left and sent to the middle.


It's simpler to go with first concept because I can only see the second concept confusing most.


Now I've been working on the idea to use centre rear with this idea, and I'll leave that until I've evaluate the idea a bit further in theory.


If you try this idea out and send all channel pink noise and then engage the Dolby stereo pro-logic decoder to ON it will subtract some of the pink noise from left front and right front and rear left and right. But you will need at least two decoders for this to work. Once its all playing in stereo there should be a more realistic movement as its been shifted along the sidewalls and rear.


There might be some strange musical moments as well since the decoder will be looking at signal passing into it. most films don't often have this equal level of sound and few now and then in six-track Dolby stereo digital process may not have any surrounds present because the mixing engineer re-recoding mixer has placed all the sound over LCR.


Few films that often have this type of effect that spring to mind are, Far and Away (1991) Forrest Gump (1994) and Black Rain (1989).


The few films that I have discovered with the side middle wall surround effects are Saving Private Ryan E..T the extra-terrestrial (1982-2002) Flight Plan (2005) and I believe Goldeneye (1995).


One moment to listen for on Flight Plan is chapter 3 where the passengers are placing carry luggage in the overhead compartments, you'll hear the sound at the fronts left and right at different intervals while hearing the sound on the surrounds left and right. So if you use the decoders to centralize the sound to the middle sidewall it should open up a bit of space in front and on the rear as well.

 

·
Banned
Joined
·
5,125 Posts
Discussion Starter #6
The newest find to add to the sidewall centre middle surround is The Mummy (1999)


In chapter 5 The Magi Strike Evelyn Carnahan (Rachel Weisz) is grabbed and trust against the wall and questioned about a (map and a key) she looks puzzled and her eyes move towards a table in her cabin, the Magi looks at the table just when Richard 'Rick' O'Connell (Brendan Fraser) yells out Evelyn that's sounded on the front left and rear left at the same time, thou rather disorienting with its foggy localization. It does make me turn my head to the left thou with two sources of sound coming from different locations spaced out along the left side does make it difficult.


There is logical Mummy solution one that has been around for quite some time now and this little black box of magic can eliminate the issue thou it would take a bit of practice to finesse it.


Using several good ole Dolby matrix decoders placed between the (rear left and front left) and (rear right front right) will be looking for anything that is placed in-between. Unless its positioned left front with no other identical sound thou there might be a sound effect or part of the music that will be placed in centre middle wall creating not a real centre sidewall effect but rather a matrix sidewall effect.


This will still work with centre back and like I said several decoders would be needed for special installations due to cost which is no more than burning it all on AVR that will be obstacle within a few mouths down the road. This is should be treated as a custom set-up and not open for arguments, this is mealy a discovery to see how many film soundtracks will feature, sidewall centre middle effects.


What will happen once connected up and calibrated for equal timber balance, you should notice part of the left front signal and rear left signal diverted to the middle centre sidewall surround. Same applies to the opposite side.


Please be aware this is backward capable so if you what to bypass this mode then select the Dolby pro-logic mode to off or on which ever.


I'm looking into the possibly of getting the centre back surround to integrate with the re-plugging configuration as it would drive most nuts! LOL




Chapter 10 The Bringer of Death 62 minutes 41seconds had another centre middle surround effect, so there are plenty of effects in this film that can surround you from multiple of positions.


When Evelyn gets separated from the others Jonathan calls out Evy! that is heard on left front and rear left at the same time, and yet slightly foggy, but it's still heard, but foggy.


So now that I have come across so many of these type of mixing effects I know the concept would work.










 
1 - 6 of 6 Posts
Top