Film-Tech Forum ARCHIVE: Dolby EX question

This is topic Dolby EX question in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ken Lackner (Member # 1002) on 07-17-2004, 01:24 AM:

This is a question out of pure curiosity. When an auditorium that is equipped for EX is playing a standard 5.1 film, how are the rear wall speakers treated? Are they simply not used? Or are they treated like they are in a conventional 5.1 auditorium, where the one(s) to the left are part of the left surround channel, and the one(s) to the right are part of the right surround? If that is the case, how does the processor do this if the rear speakers are connected to their own amp in an EX configuration?

Posted by Paul Linfesty (Member # 214) on 07-17-2004, 01:33 AM:

The rear speakers are actually attached to two sets of amps (devided up by left and right rear). When in EX mode, the same decoded EX signal is sent to both groups of rear speakers, when in bypass mode, the rear left is sent the same signal the left wall speakers receive, etc.

Posted by Ron Lacheur (Member # 1126) on 07-17-2004, 01:35 AM:

When EX isn't running, the back surrounds just revert back to the standard 5.1 configuration.

Posted by Manny Knowles (Member # 1171) on 07-17-2004, 02:18 AM:

I tried this way back with a CP500 and an SA-10. The adapter had to be manually engaged for either EX playback or bypass and it was possible to play a 5.1 mix with EX decoding enabled. When we had finished the installation, I ran some reels through it to see what would happen if a projectionist left the SA-10 enabled by accident after an EX show had moved on.

As it turned out, there was nothing super-special on those particular surround tracks and I couldn't honestly tell you that I heard anything "interesting" or "different" due to the enabled SA-10. Still, it's probably fair to say that you could get some unintended/unpredictable/undesirable results by playing a 5.1 mix with an SA-10. It would obviously depend on the mix.

My guess is that any identical Ls/Rs effects would suddenly appear to emanate from the back wall. This would be particularly jarring if a single element of a compound-effect was steered away from the mix (and onto the rear wall) as a result of unintended EX "decoding."

With a CP650DX, under ordinary circumstances, it shouldn't be possible to run a Format 10 track in Format 13 since the 650 makes use of EX flag data and "knows" when to switch between 10 and 13.

This seems obvious to me but I'll say it anyway:

In practice, it would be inappropriate to process a 5.1 mix for playback with EX processing enabled, even if said mix seems to be improved by the misapplication of EX processing technology. This would be a matter of personal opinion and would undermine the intent of the filmmakers.

Posted by Ferdinando Innocenti (Member # 2477) on 07-17-2004, 03:23 AM:

If you have a SA-10, and the switch is “Disabled”, you have a normal 5.1. SA10 (and so the CP650 EX board) processes surround signals and directs them to the right amplifiers; if it’s “Enable” signals will have a different treatment and will go in two back amps, if not, signals will pass through back amps too(normal 5.1), but not treated as EX by SA10. The SPL is adjusted during installation both in SA10 internal controls and amplifiers volume
Ciao
Nando

Posted by Antonio Marcheselli (Member # 373) on 07-17-2004, 04:52 AM:

Hi Manny!

With a 650EX you can show a 5.1 in EX using the format 13 selection (usually on U2 button). I believe that it is not possibile to show a EX feature in 5.1, for the auto EX feature...
Bye!
A

Posted by Ferdinando Innocenti (Member # 2477) on 07-18-2004, 05:52 AM:

Antonio,
you can disable the auto surround EX from CP650 menu, if you like, such as for "testing purposes",as Dolby says.

Ciao
Nando

Posted by Gordon McLeod (Member # 33) on 07-18-2004, 10:58 AM:

In many of the older wide theatres with CP200's the mono surround output was wired to the back wall to reduce the pingpong effects of poor coverage in very wide lowceiling theatres

Posted by Antonio Marcheselli (Member # 373) on 07-18-2004, 05:53 PM:

Nando

You're absolutely right, I completely forgot it...

Bye
A

Posted by Oliver Pasch (Member # 1335) on 07-19-2004, 11:40 AM:

Playing 5.1-films in 6.1 by setting a SA-10 manually into EX-mode or a CP-650-EX to format 13 is (well, not really, but let me describe it a little provocatively) called "ProLogicIIx" for home-cinema-gear and there legalized by the manufacturer as a trademark to earn even more money, whereas we poor "reel"-cinema-folks still have to subdue sound-reproduction to a standard, that doesn't exist, which is presenting a movie the way it's pretended to meant to be heard. Or does anybody out there really play at 7.0? Thank you.

The story of the success of "EX" as it's advertised by the manufacturer is a strange one: never before has hardware for a new format been sold faster in large quantities, clearing stocks of a third-world-cinema-processor with a new front panel, but also never before software (that's supposed to mean films or movies) in the new format has been so rare. Actually, my impression is, that there's only one sound-designer left, who supports "EX", and that's Gary Rydstrom (besides some unknown sound engineers in India mixing soundtracks that will stay unknown to the rest of the world). I think there is no need to discuss that films such as "Spiderman 2", "Day after tomorrow", "Van Helsing", "Troy" would have provided wonderful agar for an "EX"- (or even "ES"-)soundmix with no disadvantages for those playing "only" in 5.1.

Compared to that it's remarkable that the home-cinema-world enjoys one EX-remix-release on DVD after another.

Folks, that's not good, because it suggests to audiences that hearing a film at home is better than in our theatres. It's again us exhibitors having paid too much money for worthless equipment: we have three digital formats plus surround-EXtension, never play more than one at the same time (and will now, by the way, be forced to upgrade our good old analog sound with red light to maintain a proper backup-only format, with no benefits for us or our audiences at all).

Posted by Ted Costas (Member # 473) on 07-22-2004, 06:37 PM:

M. Night's latest film, "The Village," is an Surround EX film.
It rocks! I'd love to tell you more but I'd have to kill Brad Miller and John Pytlak, ha, ha.

Yours, Ted

Posted by Steve Guttag (Member # 268) on 07-22-2004, 07:42 PM:

Doing a Cast-n-crew show next week of The Village. I suppose I should set the "EX" button to "on"

Steve

Posted by Steve Kraus (Member # 476) on 07-23-2004, 10:14 AM:

Let's hope it's labeled properly. One shouldn't have to find this out online in order to do the job correctly.

Posted by David Favel (Member # 1125) on 07-25-2004, 06:39 PM:

Shark Tale trailer is in EX, however that means nothing these days. Will wait with "baited" breath.