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Author Topic: Aligning Sound Heads
Andrew Bangs
Expert Film Handler

Posts: 148
From: Kerrville, Texas, United States
Registered: Sep 2008


 - posted 09-10-2008 12:52 AM      Profile for Andrew Bangs   Author's Homepage   Email Andrew Bangs   Send New Private Message       Edit/Delete Post 
Is their a special tool used for Aligning Sound heads accurately or is it done by eye and ear? I have a Dolby CP650 unit. in a Horizon Projector. Here is a rough picture of what it looks like. the top eye is the standard Analog and the lower one is the Dolby Digital.I can Loosen the light sending unit with an allen wrench then twist and pull it on the shaft but I am doing this by eye. in theory when the alignment is good their should be a green LED on the Dolby Eye. But no matter what I do I can't seem to get it to light up solid. I get it to flash on and off. but never solid. Is their something else I am missing?

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Monte L Fullmer
Film God

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


 - posted 09-10-2008 01:21 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Aligning Dolby Dig readers take a loop of new roll of CAT-69 1kz tone film and an "O-scope" to read the actual track on the film and to get it aligned correctly.

One can also use a new, unused trailer with a SR-D track on it as well for a loop.

good luck-Monte

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Demetris Thoupis
Phenomenal Film Handler

Posts: 1240
From: Aradippou, Larnaca, Cyprus
Registered: Apr 2001


 - posted 09-10-2008 01:40 AM      Profile for Demetris Thoupis   Email Demetris Thoupis   Send New Private Message       Edit/Delete Post 
With the movement of the LED you will be able to achieve perhaps good ilumination. To see this without an osciloscope you need to set a dip switch on the CP650D (I think is dip switch 6 but I am not sure) to get the Cp650D to setup mode and scroll towards the video level seletion. From there when you move the LED for the digital reader you should see it moving from low volt to maximum 4.1v (if it is higher then you definately need a technician to come in to do alignment). It seems that the leds on these bracket move together but I may be wrong. To do a proper alignment of the soudheads you will need osciloscope and realtime analyzer or the CP650D software. Note that by fliping the Dip switch, should you change anything else you might lead yourself into trouble so if you are not fully aware of the procedure to properly aling a CP650D. I recon that most probably the LED level has faded and there should be a potentiometer adjustment somewhere on the projector to raise the LED level higher. The main issue that you need to achieve 4V of video level. If you have 4V and still have faulbacks to analogue then surely you will need a tech to come and do a proper alignment. Note that the Digital reader is the most complicated to aling unlike the analogue which in most cases its pretty straight forward. Whatever you do, DO NOT move the reader. Hopefully they are set ok from the factory or your technician.
Demetris

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Monte L Fullmer
Film God

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


 - posted 09-10-2008 05:27 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
You CAN eyeball it in, but close enough really doesn't merit absolute accuracy....and SR-d is critical with error counts if not accurate.

(......why you best need the 'scope' to eyeball that LED to get it dead center with the SR-D track with the film running....)

There is a subsitute program that a lot of us tekkies have and that is WinDRAS 2.0 - a program installed in a laptop and with a serial cable attached to the processor and laptop to "see" what the camera eye is seeing on the film.

This program works as a 2nd best to the actual testing above.

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Louis Bornwasser
Film God

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


 - posted 09-10-2008 08:57 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Careful with that program. You are "looking" after delay and error correction. Louis

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Steve Guttag
We forgot the crackers Gromit!!!

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


 - posted 09-10-2008 09:07 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
I'm sorry to say this but stop...you are shooting blind without the proper tools and training. Nothing in the soundhead should be done stictly by eye or ear. You need both calibrated test films as well as the proper tools which include, WinDras, O-scope, test films and RTA. It really is that cut and dried. Anything you do by eye is likely to be as bad as it is good.

Despite what Monte said, WinDras can be a very valuable tool but not for setting the LED position so much...it can be handy for items. If you know how to read the quick histogram, you can use that portion of Dras to set LED/lamp intensity.

I'm not trying to discourage anyone from trying to improve things but the reality is that without the proper materials and training, I would think you have as much chance to make things worse as make them any better and you are not going to get it right, even if you do, by luck, improve things a little.

Steve

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Tim Reed
Better Projection Pays

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


 - posted 09-10-2008 10:20 AM      Profile for Tim Reed   Author's Homepage     Send New Private Message       Edit/Delete Post 
Steve is absolutely right. This is not for the faint of heart (or inexperienced/untrained). It's quite a bit more involved than setting up A/V equipment.

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Louis Bornwasser
Film God

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


 - posted 09-10-2008 11:07 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Whether it helps or not is almost totally dependent upon how badly it was aligned before you started! Louis

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 09-10-2008 11:11 AM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
I never thought DRAS was meant to align or set up a Dolby Digital system. Only to perform simple checkups on a system that has already been aligned using a scope, test film and an analyzer.

In other words, DRAS would be used by a technician who receives reports of problems with a system. He can quickly hook up his laptop and get a readout on the system's performance without dragging out all his equipment.

If he finds that there is a problem, he can fix it the right way but, if it's only a minor tweak or if he determines that the problem will keep until he has time to make a regular service call he will save himself a lot of work.

I would never use DRAS to do a full alignment.

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Monte L Fullmer
Film God

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


 - posted 09-10-2008 12:45 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Some also run DRAS parallel with the full testing, but true - never by itself to get absolute results.

What I'm wondering also is with the Horizon having a basement reader: how's the wow and flutter with these machines?

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Andrew Bangs
Expert Film Handler

Posts: 148
From: Kerrville, Texas, United States
Registered: Sep 2008


 - posted 09-10-2008 10:57 PM      Profile for Andrew Bangs   Author's Homepage   Email Andrew Bangs   Send New Private Message       Edit/Delete Post 
First off thank you all. Frankly you have confirmed my own feelings and now I feel I have the facts to go to my superiors and ask for a tech to come out. I am an adventurous sort and have always learned by doing. but I have always had the Knowledge on just what I was qualified for or not as I could easily do more harm than good. this situation seems like it needs the definite touch of a professional. I think ore trouble began with poor Maintenance. Things became loose in the projector and with addition of unqualified hands jarring around the insides cleaning other components the problems were (no pun intended) Amplified. The other problem I have is that as Monty Eluded to with the digital gone the analog is now playing the audio and yes their is distinct flutter and I cannot get rid of it.

I do realize I may get Booed and Hissed for this but does any one know if their is a sister program to WinDRAS 2.0 for the Mac... [Eek!] yes I said Mac... [Confused] if so please let me know and also if the program has a price I will have to swing that by my boss. If their is no Mac Version I have a lead on a PC that I might be able to use. The thing that is most interesting to me is being able to look through the lens of the reader. I feel that if I could do that I might be better able to cut down on the flutter. Do you know of a way to get the lens feed from the Analog as well as the digital. Will this program do both?

I only ask because the analog and digital on this machine is well out of tech spec and frankly right now we are loosing people to the background noise so something needs to be done immediately till a tech can make it out.

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Monte L Fullmer
Film God

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


 - posted 09-10-2008 11:24 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
There are some FT members who also have MACs instead of PC's, thus it could be possible that Dolby has a MAC version of DRAS - have to chek the Dolby site for that info.

WinDRAS is only for the digital side of the audio spectrum.

Optical is a whole different animal to align, yet more basic testing alignments techniques than with digital.

Yet one has to do the optical alignments first before the digital alignments for a basement reader.

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Joe Redifer
You need a beating today

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


 - posted 09-10-2008 11:32 PM      Profile for Joe Redifer   Author's Homepage   Email Joe Redifer   Send New Private Message       Edit/Delete Post 
No. Dolby hates Mac users. If you have a recent Mac laptop, however, it will have an Intel processor. Simply install Windows XP under "Boot Camp" and your laptop will be able to boot into Windows and run your DRAS. However you can bet that DRAS requires some bizarro, outdated PC-only connection from 1975 like a printer port or serial port to work... things that Macs don't have. Asking them to work with technology less than 10 years old like USB is simply asking way too much of Dolby! They'll support USB when it starts disappearing from computers.

Hopefully I'm wrong and someone in the know can correct me, but I bet I'm right.

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Monte L Fullmer
Film God

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


 - posted 09-10-2008 11:38 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Yea, the good ol' DB-9 thru serial connection. But, you can get USB to serial adapters (which I had to get for my recent laptop..) which works great.

But, it's also handy to keep an old Pentium 266 laptop running Win98 floating around for the use of WinDRAS for then you definitely got serial ports to use.

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Joe Redifer
You need a beating today

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


 - posted 09-10-2008 11:39 PM      Profile for Joe Redifer   Author's Homepage   Email Joe Redifer   Send New Private Message       Edit/Delete Post 
Did it work with DRAS?

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