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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » DTS and Dolby Digital with Ultra-stereo

Author Topic: DTS and Dolby Digital with Ultra-stereo
James R. Hammonds, Jr
Jedi Master Film Handler

Posts: 931
From: Houston, TX, USA
Registered: Nov 2000

 - posted 02-14-2001 09:06 PM      Profile for James R. Hammonds, Jr   Email James R. Hammonds, Jr   Send New Private Message       Edit/Delete Post 
I went back to work at one of my old theatres this past weekend, and was faced with a problem.

This particualar theatre uses ultra-stereo js-200 for our stereo processing, and also uses portacle dolby digital and dts units which connect to the ultra-stereo through an interface.

The problem we have is that when we hook up out dts, the ultra-stereo will switch from stereo to digital as soon as something tht is on the disks for that particular feature is read.

The only problem is, when that trailer is over and the next trailer (or one of our snipes) that does not have dts is played, the ultra-stereo switches back to stereo/sr instead of stereo, regardless of how the automation on the projector is set, which results in a theatre with no sound.

To save you the trouble of having to ask the question "why would you want it to go into stereo when almost all prints are encoded with sr?" the answer is i dont know.
the system is set up so that all the analog aound plays through either the stereo or mono buttons, and in the case of dolby digital or dts, the digital button.

So my question is, how do we set it up so that when the dts quits reading for whatever reason, how do we make it default back to stereo instead of sr?

Also, in order to switch the sound to digital for dolby digital, we have to put a cue at the beginning of the feature and set the automation on our projector to do so.
Is it possible to set things up so that the dolby digital kics in automatically and switches back to stereo when a non-dolby digital clip goes through so we can play our trailers in digital when we play films in dolby digital?

I realize that knowing certain makes and models of some of this equipment may help to figure some of this out, so if need be, ill write all of it down when i go back this weekend.

Randy Stankey
Film God

Posts: 6440
From: Erie, Pennsylvania
Registered: Jun 99

 - posted 02-14-2001 09:17 PM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
Take a look at the back of the USL processor. How does the DTS connect to it?

There could be two separate cables going from the DTS to the USL, or there could be one ribbon cable that branches off to two places on the USL.

One of those connectors (be they individual cables or branches of the ribbon cable) goes to the sound input of the processor. The other one goes to the automation inputs. This second one is the one you want to look at.

Is it a single PC board that just screws into the terminals? OR is it a PC board that has wires comming from it which are connected to the automation input terminals on the backplane of the USL?

If you have the second one, you're in luck. Just switch the wire that goes to the "SR" input to the "STEREO" input.

Now for the question: Why does the system go dead when you switch the processor to "SR"? Do you not have a SR card installed into the processor?

John Eickhof
Jedi Master Film Handler

Posts: 587
From: Wendell, ID USA
Registered: Jan 2000

 - posted 02-14-2001 10:58 PM      Profile for John Eickhof   Author's Homepage   Email John Eickhof   Send New Private Message       Edit/Delete Post 
Actually Randy is correct in that the DTS has an interface board for the automation selection on the back of the USL processor, either type has a small 'suitcase' jumper that pre-selects fallback mode from digital to either 'SVA' (Stereo) or 'SR' if the jumper is missing the DTS will switch to SR every time, if you want it to switch to SVA then solder a wire between the two pins that are marked 'SVA' Or you can purchase an SR card from your equipment dealera and be able
to playback SR prints correctly!
As for your second item, at this time there is no other way to pre set the dolby other than manually cuing it to SR-D as you are doing! It is unfortunate that Dolby built in this function in the first place, in fact their unit is the ONLY one that wil not automatically sense and play it's sound without a manual cue at the beginning of the day. (As long as the unit is turned on after the first cue, no additional cues are necessary)

John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258

Randy Stankey
Film God

Posts: 6440
From: Erie, Pennsylvania
Registered: Jun 99

 - posted 02-14-2001 11:15 PM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
I was thinking that since it doesn't seem like he is equipped for SR playback that it might be better to not even use the SR option on the thing to begin with. That's why I said to move the wires. (If it's the kind that has wires)

That way he'll never have to worry about accidentally switching to the wrong sound format.

Brad Miller

Posts: 17695
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

 - posted 02-15-2001 12:47 AM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Dolby's more recent DA20s are being shipped with a card (forget the cat's the last one on the right) that can be set to auto-sense and switch into digital.

Gordon McLeod
Film God

Posts: 9470
From: Toronto Ontario Canada
Registered: Jun 99

 - posted 02-15-2001 08:49 AM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Another solution is to move the nr card to the SR slot since they are intechangeable

Karen Hultgren
Master Film Handler

Posts: 492
From: Agoura Hills, CA, USA
Registered: Mar 2000

 - posted 02-16-2001 03:55 PM      Profile for Karen Hultgren   Author's Homepage   Email Karen Hultgren   Send New Private Message       Edit/Delete Post 

If the DTS is forcing the US to SR and you don't have SR cards, then look at the logic interface board between DTS & US. If you have a DTS-6D (3-drive unit), you should be using the D571. On this board is a jumper that steers the default (to analog) pluse to always go to "A-Type". See DTS-6D manual, page 47 (Sept28, '99). Once set, the US will always default to A-Type **EXCEPT** at show end - the DTS will still pulse the US to nonsync at show end.

Let me know if you have any other questions.

Karen at DTS

Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12295
From: Annapolis, MD
Registered: Dec 1999

 - posted 02-17-2001 02:26 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
The way I'm reading this, we have a fixed JS-2XX system (probably the JS-260) and roll-around or in some way portable digital systems (both DTS and Dolby Digital).

If this is the case, then you are at the mercy of the designer of the portable system. You may not have the DTS logic board to redirect the "SR" pulse to stereo. Futhermore, Dolby ALWAYS reverts to SR. How ever, there should be some sort of interface that does go to the "automation" terminals on the Ultra Stereo and the key is to move the signal to the Stereo terminal and not the SR terminal.

I know on our roll-around systems, we place a switch on the roll-around rack for DTS so the operator can program it for either A or SR fall back (our racks were designed in the day of the DTS-6, not the 6D). For Dolby, our racks had the DA-20 get a pulse on power up to have it look for digital so it would jump in when it had good signal. We also had a hidden switch for "A" fall back, just in case.

BTW, Brad is correct, that the later DA-20s CP interface module has "auto-digital" for those that want it and is programmable to retain the "only give me digital when I want it, DAMN IT!"


"Old projectionists never die, they just changeover!"

Ken Jacquart
Film Handler

Posts: 82
From: San Francisco, CA, USA
Registered: Mar 2000

 - posted 02-17-2001 08:11 PM      Profile for Ken Jacquart   Author's Homepage   Email Ken Jacquart   Send New Private Message       Edit/Delete Post 
You're right Steve, and the card is a Cat611A. You can set it for auto-digital, digital always, or normal pulse control. The older Cat611 can simply be pulsed to Digital once, and then will go back and forth between SR and Digital as necessary.


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