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» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » DTS "glide time" (Page 1)

 
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Author Topic: DTS "glide time"
Mike Olpin
Chop Chop!

Posts: 1852
From: Dallas, TX
Registered: Jan 2002


 - posted 06-22-2003 05:31 PM      Profile for Mike Olpin   Email Mike Olpin   Send New Private Message       Edit/Delete Post 
With all of the bad DTS prints currently in circulation, I was wondering if there is a way to increase the "Glide Time" on a DTS unit. (the amount of time between timecode interuption, and drop out)

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 06:02 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Mike, I don't think it is possible without re-engineering. When the buffers dump, that's it. It is going to default to analog.

I agree with your statement in a different thread. It is a great format. Probably the best. But the reliability problems of disks, prints, and the unit itself (as compared to SRD) I have to admit I am starting to "think twice" about installing more DTS units. As far as hardware is concerned, every one of our units in our small chain (as well as the spin-off of our chain) has had the DTS6-AD (and the DTS6-D) units in for "rework" at least once. Some have been in twice. As far as I am concerned, that is unacceptable.

To give you an idea, I have a CP-55 in "standby" mode in Anacortes, configured with "D" connectors for quick connect in event the 6AD takes a dump. I shouldn't have to go to these extremes. However, I don't have enough CP-55's to place in standby service in the other 5 screens. In Stanwood, they have a "roll-around" DTS-6AD that doesn't work because of drive failures. Whether McRae ever upgraded it, I don't know at this time.

In a favorable note, I have not had any problems with compatibility issues with the DTS-6D when being used with the analog processors such as the JS series Ultra Stereos or the CP-55 and 65 Dolby units.

Now that the bugs have been worked out of the DTS6-AD (those should have been worked out long before the units were released) we are facing quality control issues with the disks and prints. What's next?

I hope Karen and DTS in general take note of these threads. Their very survival could depend on it.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 06-22-2003 06:08 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
There may be one way to do this. That is to run an E175 time code generator instead of reading the TC on the film. Assumming you don't loose any frames of film and there is a shaft encoder on the projector threading at picture start in the gate and then relying on the shaft encoder to drive the E-175 which can output DTS time code it all ought to stay in sync. The E-175 is looking for 240 Pulses Per Revolution of the encoder for every frame of film. Its pretty simple and many Large format theatres run this way. I would think that any theatre could also do this.
Mark @ CLACO

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 06:12 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Mark, If that worked that would be great. But I see more things to fail. [Frown]

I think the best solution is for the personnel involved to "get it right" the first time.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 06-22-2003 06:13 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
quote:
I would think that any theatre could also do this.
For less money than just installing SRD? Know how many SRD units I have seen fail since 1992? None.

The way I see it the format design is very reliable provided dts steps in and ensures that these disc and print issues (obviously done "out of house") are kept under tight standards. That is the key to the format working in my opinion. With the hard drive based system coming out, the only real weak point will be the prints and discs themselves.

Has anyone done my old paper towel trick yet? It involved wrapping a few layers of a thick paper towel behind the main roller to add a drag (but not enough that it prevents the roller from spinning). Many a prints that had timecode popping in and out would play fine with the towel in place. Simply "adding more rollers" or positioning the rollers such that the film wrapped moreso around them does not add enough tension to even bother with, especially when they are all ball-bearing based rollers.

I'll see if I can find a picture of the quick and dirty modification and post it. The best part is that it won't void your warranty, unlike jacking with the lateral adjustment.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 06:15 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
I have seen only one CP-500 fail. Water got into it because of a roof leak.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 06-22-2003 06:26 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
I just took some quick shots from my rental unit to show the drag...

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Normally if you were to give the main roller a spin, it would spin multiple revolutions. With the same spin, the roller only turns maybe 1/2 revolution. (Again, this should NOT prevent the roller from spinning when film is running through it.) This greatly helps to smooth out the bumpiness from a bouncing platter or feed reel as well as projector vibration. Timecode does track better this way. Just be prepared to change out the paper towel once every year or two.

BTW, the thicker the paper towels the better. The best I've found is something UA used to buy called "Value Choice" heavy duty wipes. That is what is shown here (cut down to size, of course).

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 06:29 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Good idea, Brad.

Another thing that helps is the use of the film cleaner. That smoothens it out quite a bit, especially if the platters are the A3's, CFS, or Potts.

Christie AW3 could suffer the same problems if someone removed the impedance spring from the center roller. The film just might bounce all over the place on its way to the projector. Obviously that is not too cool, and it could drive the time code reader nuts.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99


 - posted 06-22-2003 06:55 PM      Profile for Joe Redifer   Author's Homepage   Email Joe Redifer   Send New Private Message       Edit/Delete Post 
I like it when people say that DTS would be a great format if everything that was wrong with it were fixed. What format wouldn't? CDS would rock if everything bad about it was good instead.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 06:59 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Joe, you could bet your butt on that one..... [thumbsup]

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 06-22-2003 07:12 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
I don't like that impedence spring at all. I've found that it requires constant maintenance to keep a smooth payout. So long as your rollers are in good shape, simply removing it provides a nice smooth payout without too much tension.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 06-22-2003 07:20 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
Why is everyone having DTS issues all of a sudden? Aside from bad drives (a problem which is largely gone by now), I've never had any major issues with the format, assuming that the disks arrive with the print. One theatre where I used to work was set up (badly) such that the CP200 wouldn't fault to optical if the DTS unit failed. They ran that way for over a year and never had any problems.

I don't currently work anywhere that has DTS; of the three or so theatres where I currently fill in on a semi-regular basis, two are single-screens with mono (yes, still), and one is a multiplex which has SRD on three of six screens. I love SRD for its huge advantage in title availability and for its single-system design, but I've had no end of troubles with the basement readers in Simplex Five-Star soundheads. Prints which play with moderate error rates (5-6) on the cat. 700 simply won't play at all in SRD in this theatre (yes, the same prints). This theatre has a very good tech, so I don't think it's an alignment issue.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 08:00 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Scott, I think it has more to do with the frequency of the DTS issues, and people like me are getting a little annoyed by it.

I agree with Brad on the impedance spring. But I have noted that it does make a difference in stability if it were intact. Maybe not much, but I have to say it helps the entire issue if the spring was working the way it is supposed to....When I was at Stanwood, I still used them, but it was a pain in the butt sometimes.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 06-22-2003 08:39 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
In theatres with a long travel distance from the platter to the projector I used to get timecode dropouts from the jitter introduced by film sag
I started taking old 4 track penthouses and cutting the front off them and mounting a dts reader where the mag head used to be and let the davis tight loop damp it out
this is a simplex one I did the motiograph works the best

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 06-22-2003 08:44 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Josh, if you are following this thread, I have some Simplex penthouses as you know...and if we get a DTS for your booth, I'll give you one of those to follow Gordon's suggestion. [Smile]

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