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» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Penthouse digital readers (Page 1)

 
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Author Topic: Penthouse digital readers
Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999


 - posted 11-15-2007 05:40 PM      Profile for Frank Angel   Author's Homepage   Email Frank Angel   Send New Private Message       Edit/Delete Post 
We are going to add SRD playback to our Simplex XLs which already have DTS. Anyone have a preference for any particular manufacturer's penthouse reader? BACP DSTR-20 say over Dolby's?

Here is another issue. We already have an Ampex mag penthouse (which has to remain) and a DTS code reader on top of that. Will there be any issue if we stack the SDR reader on top of these two in terms of separating the reader that far from the picture aperture? I know that you can adjust the delay to match, but I was told that the more the delay, the more harsh the sound because there is more digital processing needed when you are at the maximum delay rather than the minimum. True?

If this IS true, would it be better to put the SRD reader on top of the mag penthouse and then the DTS on top of that? I am assuming the DTS has enough leeway to deal with the longer offset.

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004


 - posted 11-15-2007 05:44 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
You can stack the SR-D reader on top of the DTS unit with no problems.. Just change the delay timing for the SR-D unit being on top of the reader...and the manuals should have that timing reference.

Plus, the length of delay setting has no effect on sound issues since it's just picking up data from the film-why of the great variances of delay setting to accomodiate almost any extreme of installation..from minute to extreme.

Actually, it helps the film feed through the DTS with that SRD reader above since that reader has the registry pins on the center sprocket, plus the flywheel to smooth the film speed to the DTS reader...

Plus, BACP units are somewhat more economical to have than the Dolby and still is compatible with the Dolby processor units.

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Al Biers
Film Handler

Posts: 13
From: Speedway, Indiana USA
Registered: Oct 2003


 - posted 11-15-2007 06:19 PM      Profile for Al Biers   Email Al Biers   Send New Private Message       Edit/Delete Post 
Both the Dolby and BACP readers are great but I prefer the BACP for one reason, the ease of changing the LED when it goes bad, Dolby you have to solder a new one in, BACP just remove 2 screws and replace with new.

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Ron Curran
Jedi Master Film Handler

Posts: 504
From: Springwood NSW Australia
Registered: Feb 2006


 - posted 11-15-2007 06:32 PM      Profile for Ron Curran   Author's Homepage   Email Ron Curran   Send New Private Message       Edit/Delete Post 
We have no troubles with the Dolby reader stacked on top of the DTS reader. Of course, we have to lace through both when running Dolby Digital to mainain sync.

The only issue you will have is with some used prints where the DD will often fail, though I am sure you have read this in other posts.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005


 - posted 11-15-2007 06:45 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Why not use a "basement" reader. They work quite well in SH-1000 soundheads. Then you don't have these problems. Louis

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 11-15-2007 08:37 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
In answer to Louis, I was the main proponent of the basement reader idea and helped all the manufacturers design and build the various versions during my time at Dolby Labs.

All else aside, it's a plug and play world and there are not enough techs and patience to sort out SR.D problems when they arise. It's simply easier to let the factory deal with the problem.

The versions that had the most problems IMHO were Christie and then Century, both in large part for internal vibration problems that resulted in vertical jitter the SR.D process could not handle.

In theory, the basement reader is a better and cheaper way to read the bits, but in practice, only Kinoton pulled it off close to perfectly.

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999


 - posted 11-15-2007 08:52 PM      Profile for Tim Reed   Author's Homepage     Send New Private Message       Edit/Delete Post 
Oh, no question... BACP. Sam has a great product and the best value.

(Hi, Al, glad to hear from you!!!! [Big Grin] )

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 11-15-2007 10:56 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
Thanks for the kind words but I did not write in to draw attention, just to get back to original topic.

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999


 - posted 11-15-2007 11:22 PM      Profile for Tim Reed   Author's Homepage     Send New Private Message       Edit/Delete Post 
Oh, I know, Sam. I was just responding to Frank's inquiry.
[Wink]

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 11-16-2007 08:27 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Sam's readers have been the best as for results for us too. Basically zero problems with them.

quote:
Dolby you have to solder a new one in,
Dolby also offers the entire LED head from the CAT 701/2 penthouses as an assembly with the LED pre-aligned. This way its alot less painful in the field to replace them. The proper alignment of the led is done in a jig as are Sam's when they are built up. For field replacement replacing the entire head on either the BACP or CAT 701/2 units is the best and most accurate way to sucess.
BTW: The new Christie belt kit gets rid of all the verticle jitter on the P-35!! BAsement readers will finally work quite good.
Mark

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 11-16-2007 08:42 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Just like Sam has to defend his reader...I must defend my basement readers...Simplex, Century and Kinoton...no instrinsic problems there. AND if you fix the problems causing digital failure, you also fix problems degrading the analog sound.

I can't tell you how many times I've come into a penthouse booth where there is zero tension on the tension rollers and the digital is in a failed state. Penthouses are no guarantee to perfect tracking...people can still screw it up. My theory is that they will be threading the analog soundhead anyway; there is no extra stuff.

But back on topic...between Dolby and BACP..performance wise, I see no difference. Cost wise BACP is a clear winner. LED changeout, BACP is a clear winner if you are doing it yourself...since it is plug and play. I've changed LEDs on a great many readers of many different brands so the thought of soldering one in the field doesn't bother me...Ernemann does require an RX LED bracket...since their's is glued in (we can remove the glue and install a new LED but given the solvents and cure time...not really field practical.

So add up the points and I think the BACP reader comes out on top (pun partially intended).

Steve

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Mark J. Marshall
Film God

Posts: 3188
From: New Castle, DE, USA
Registered: Aug 2002


 - posted 11-16-2007 11:06 AM      Profile for Mark J. Marshall     Send New Private Message       Edit/Delete Post 
For what it's worth, our CP650 / CAT 702 setup still warbles. I think we're going on three years now. So do the two down the street. We tried switching the CAT 702 to be under the SDDS reader hoping that the SDDS reader would smooth out the motion in the SRD reader enough to make the warbling go away, but it didn't. It still wows badly when a splice goes through, or cue tape goes through.

The tension is fine in the readers, and our engineers can't do anything more with them. They say that they talked to Dolby and the response was "It's supposed to do that." I'd love to see it work like the 10+ year old CP65 / DA20 / CAT 699 setups down the street which both work perfectly. I've always been a big fan of Dolby, but I've given up on this particular setup. Everything in that house runs in SDDS or SR. A basement reader might help our problem, but I'm not sure.

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 11-16-2007 11:32 AM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
Apart from refuting Steve's saying I'm defending my reader, I agree mostly with Steve. It's easier that way.

If we had all Steve and Mark clones dogmatically servicing cinemas, we would all be better off but we don't. I'm just stating the obvious when I say we live in a plug and play world.

Basement readers are definitely better when it comes to wow caused by the platter jerking on the film. This was one of the inherent advantages that caused Dolby to go in this direction. The penthouses were mostly intended for the short term. The idea was we would be out of the sprocket business in a few years. Didn't happen.

As to Christie's new belt kit, let's wait and see. This may finally be the magic bullet that make the projector work properly , but time as in a year or more, is the true test here.

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Brad Miller
Administrator

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


 - posted 11-16-2007 11:42 AM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
The only thing I don't like about basement readers which hasn't been brought up is that you are putting all of your eggs in one basket. It is only for this reason I prefer penthouse readers. As far as the tracking ability goes, nothing beats a Kinoton basement reader. However I've not had problems with any other types of projectors running basement readers in them.

As much as I love to defend and support Dolby, I also agree that the BACP reader is a superior machine. The fact that it is cheaper and easier to change the led on just makes it even more attractive.

Don't worry about stacking a bunch of penthouse readers on your projector. It does NOT degrade the audio quality. Whoever told you that has no business anywhere near a booth.

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Lyle Romer
Phenomenal Film Handler

Posts: 1400
From: Davie, FL, USA
Registered: May 2002


 - posted 11-16-2007 01:18 PM      Profile for Lyle Romer   Email Lyle Romer   Send New Private Message       Edit/Delete Post 
quote: Frank Angel
I know that you can adjust the delay to match, but I was told that the more the delay, the more harsh the sound because there is more digital processing needed when you are at the maximum delay rather than the minimum. True?
Completely false. The data just gets delayed not processed in any way. Think of it as pausing a live show on a tivo. Hit pause then play and it's the same data just delayed. The only difference is Tivo is on a hard drive and on the digital sound systems it is RAM.

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