Film-Tech Forum ARCHIVE: DTS switching problems

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Posted by Monte L Fullmer (Member # 2797) on 11-01-2006, 06:11 PM:

I have an interesting problem, or situation acting up that I would like to have help on this area and to see if anybody out there is having the same issues flaring up with their older players.

I have both the DTS-6 and 6D units (both have been upgraded to v.1.46 with new drives), each tapping into USL JS-1000 series of processors. Automation are the STRONG SPA-7 dinosaurs in STRONG X-90 consoles with PR-1050's hanging out onto the front of the consoles.

Film starts and the automation pulses the JS-1000 to head to optical at dowser open. First trailer is in optical..no problems there. Next two trailers are in DTS (with data on the feature disc-no trailer disc are being used..) DTS unit pulses the JS-1000 to swing to digital, no problems there as well. BUT, after the last trailer, the JS-1000 unit pulses back to optical and when feature timecode is picked up by the DTS units, the pulse from the DTS unit will not pulse the JS-1000 back to digital. Thus the JS units have to be manually punched back into digital - and sometimes will drop out of digital and will not swing back into digital until manually pressing the digital button on the format card. I first thought it was the format card, thus switched cards with the other JS unit, but the problem didn't follow over to the other processor. I've checked automation cables from the players to processor if I have any connection problems there as well (since the 6 unit uses a large ribbon cable and the 6D uses a parallel cable..) but these are okey.

The LEDs in the readers are okey since I pass a credit card inbetween film and camera. I pass the card in front, JS-1000 pulses to optical after the data cache was depleted in the player. Remove the card and the DTS unit pulses the JS-1000 unit back to digital and begins to play back in digital as it should be.

Any help on this would be great, for it's a buggy one for sure.

thx-Monte

Posted by Tom Springer (Member # 1225) on 11-01-2006, 08:12 PM:

Monte,

I think you are switching out of DTS and then right back into digital due to the unit is still reading the timecode - DTS came out with an change quite some time ago to stop autoswitching during a small part of the end of the film(maybe five minutes)- most people solve this by using a piece of black leader at the end which has no time code.

Posted by Gordon McLeod (Member # 33) on 11-01-2006, 10:09 PM:

The odds are that the feature foil is pulsing the automation to sr or a type at the exact moment that the dts is also pulsing digital

Posted by Mark Gulbrandsen (Member # 72) on 11-02-2006, 07:34 AM:

No, its not a foil, automation, or cue related problem.... I have a unit doing exactly the same thing that I will be looking at tommrrow. What its doing is that during a string of trailers the first will play back in DTS from the trailer disk and then if the second trailer's sound is not on the disk it defaults to analog ok but then assuming the next trailer's sound is on the disk or if the feature comes up the player green light comes on but the analog processor does not get cued back to digital by the player. The operator then pushes the digital format button on the processor and everything else including reversion works fine for the entire feature. I think I had this problem once a long time ago and it was a failure of a component inside the player but can't remember exactly.

Mark

Posted by Darryl Spicer (Member # 711) on 11-02-2006, 10:31 AM:

Is this something that just started out of the blue or has been going on for a while? Is there a non-DTS in use trailer between the feature and the two DTS trailers that had working time code on them? Are both units doing it? I would suspect an internal problem with the DTS player if only one of them were doing it.

What I found in my experience with the DTS units is that with the JS-series processors you do not want a cue pulse from the automation telling the processor to pulse to stereo at the feature cue. You either need the ability in your automation set up to send a to digital cue at the feature lights down cue or if your automation does not support that selection you need to either move the wire used for the stereo pulse from automation to the digital point on the processor or just remove it since the automation pulses to stereo at the dowser open.

If the js-processor is in digital and there is still active time code being read during that feature cue the processor will switch back to stereo and will not pulse back until either 4 seconds of non active time code is read or you push the digital button on the processor.

If there is a non digital in use trailer before the feature there should not be a problem with it going to digital when active time code is read so long as the feature cue is not read at the same time as the active time code is picked up.

I have also found that the js-processors needs a good solid pulse from the DTS unit.

quote: Tom Springer
I think you are switching out of DTS and then right back into digital due to the unit is still reading the timecode - DTS came out with an change quite some time ago to stop autoswitching during a small part of the end of the film(maybe five minutes)- most people solve this by using a piece of black leader at the end which has no time code.

That's a different problem. The solution that DTS came up with I found only worked on the DTS 6D and later units. The problem still occured on the DTS-6 units. The easy solution there was to place a second end feature cue 4 seconds or more past the last readable time code.

Posted by Monte L Fullmer (Member # 2797) on 11-02-2006, 03:15 PM:

THX bunches for all the help.

Told the operator there to move the feature cue up the trailer pak where the end credits begins on the last trailer, (he is to put the feature cue there and get it away from the splice, or the lab printer join if no splice is there) an take it from there and he'll report back to me on the outcome of this, If this doesn't work, then back to square one on other suggestions that were posted then I'll post it here for future reference.

thx-Monte

Posted by Brad Miller (Member # 2) on 11-02-2006, 03:50 PM:

Just take your "mono/trailers" wire from the automation and connect it to your "SR" of the Ultra Stereo. Then disconnect the "stereo/feature" wire from the automation completely.

At that point once the douser opens the processor will be pulsed into SR and the DTS will have full uninterrupted control for the rest of the show.

There IS a catch! If by chance the first trailer picks up dts timecode BEFORE the automation pulses the processor...and EVERY trailer has dts timecode with appropriate trailer data on the discs...you could end up running your entire show in SR.

A quick fix to this is to simply splice in half a dozen feet of black leader (without timecode) between the last trailer and the feature. That way worst case senario the trailers run in SR (something I prefer anyway) and then after the timecode dropout from the black leader the dts will kick the processor back into digital no matter what. Every Technicolor lab print has this already in place. You would only have to slug in black on Deluxe lab prints.

The alternate fix if you are not running start timers and don't want to hassle with the black slug before the feature is to make sure the operator looks at the dts unit and if the green light is on to make sure that the digital button on the processor is punched up. This does still require that "stereo/feature" wire to the processor to be removed.

Posted by Steve Guttag (Member # 268) on 11-02-2006, 04:47 PM:

Once upon a time....

When we were doing the roll-around digital rack thing since the studios only supported 1 or maybe two of the digitals...

I had an interface board for the CP55/65 and CP500 that would also monitor the held digital line from DTS...it would activate 4 dip relays or MUX chips (depending on the board and revsion). What the circuit did was have all automation pulses, except non-sync, connect to "digital" if the DTS believed it was in digital...when the DTS player released its latched line then the relays allowed the automation to pulse things normally. The DTS player was also blocked from pulsing the processor digital if non-sync was the current format (used the LED status lines on the CP55/65 and the "id bits" on the CP500 to know if Non-Sync was the current format.

Steve

Posted by Monte L Fullmer (Member # 2797) on 11-02-2006, 09:43 PM:

Once again, thx for all the info. Good to know of additional tips for one to use in the future.

Talked to the operator who followed my instructions and he replaced the feature cue to where it's up to the beginning of the trailer credits in the last trailer and the problem was taken care of.

Got away from the arguments between processor and player.

thx again - Monte

Posted by Demetris Thoupis (Member # 833) on 11-03-2006, 07:35 AM:

This is a common problem with momentary and maintained relay pulses. Most probably the automation was giving a latched contact to pulse your processor into the SR feature and since it was latched, nothing else could pulse it elsewhere since probably it was using the First In First Out method. So when DTS was shooting a momentary pulse to kick your processor into DTS, the processor did not follow up the Last command since the previous command was already in place and still latched.
Demetris