Film-Tech Forum ARCHIVE: 70 mm Magnetic sound

This is topic 70 mm Magnetic sound in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ivar Corceiro (Member # 1602) on 02-12-2003, 09:11 AM:

I work with a 8/70 cinema Strong projector with a DTS sound system without time code. I can only sincronyze the sound with a bad automation system made by Iwerks, wich means if i have a problem during the session I must restart everything again. I want to buy a time code reader but, while I know this time code reader fails several times, I also need a backup sound (magnetic for example).
Our distribuiton company tell us they can´t get us a 70mm movie with magnetic soud. What can I do and where can I make a copy with both systems (DTS and Magnetic)? [Confused]

Posted by John Pytlak (Member # 331) on 02-12-2003, 09:28 AM:

Are your 8-perf 70mm prints supplied with a printed-in timecode? (DTS or otherwise?). If not, a time code reader will not be of help. Any double system sound without time code can still have a sync problem if you don't lock frame-for-frame.

You might also post the question on:

http://www.1570.com

Posted by Ivar Corceiro (Member # 1602) on 02-12-2003, 09:37 AM:

Yes, Our prints are supplied with a printed-in timecode, but someone told me this printed-in timecode is only a optical copy of 15/70 print, and that will not work in a 8/70 print. Do you know something about this?
Thank you very much...

Posted by John Pytlak (Member # 331) on 02-12-2003, 09:41 AM:

I don't know the timecode system being used on your prints, but timecode like DTS is usually printed from a dedicated sound negative, and would be the proper format for your 8-70 print. If it is indeed DTS, I'm sure Karen Hultgren of DTS can answer your questions.

http://www.dtsonline.com

Posted by Darryl Spicer (Member # 711) on 02-12-2003, 09:51 AM:

quote:
Yes, Our prints are supplied with a printed-in timecode, but someone told me this printed-in timecode is only a optical copy of 15/70 print, and that will not work in a 8/70 print.

wait a tick, didn't I read somewhere on here that there is no actual timecode on a 15/70 print but some type of system that keeps the unit in sync with the sound. Gordon would know this.

Posted by John Pytlak (Member # 331) on 02-12-2003, 09:55 AM:

Here's a list of special venue films that used DTS:

http://www.dtsonline.com/cinema/svfilms.html

Posted by Gordon McLeod (Member # 33) on 02-12-2003, 10:55 AM:

1570 doesn't usually have printed in time code so any time code should be valid
In most cases a shaftencoder on the projector (generating biphase) drives a time code generator that is controled by the automation to sync to the DTS player
As a backup purchase a 6 track magnetic film dubber that can handle the large reels and it will connect to the shaftencoder (a distribution amp for that is required) and it will chase the shaftencoder directly maintaining sync even if the projector stops

Posted by Christian Appelt (Member # 1067) on 02-12-2003, 11:11 AM:

As Gordon said, you need an impulse from the projector.
You could use a special CD player by MARANTZ/GEBUHR that will sync easily to any frame rate of your projector, look here:

http://jl-site.com/Super8/CDplayer.html

I know that device has been used for silent film presentations (with lower than 24 fps rate) to deliver the orchestra music. But what I do not know is whether you can get more than 2-channel stereo or 2/4 matrix surround.

Posted by Karen Hultgren (Member # 395) on 02-12-2003, 11:49 AM:

Ivar,

"Copy of 15/70?" No, we never print timecode on that.

Is this a special venue location? What is the name of your show?

If you are special venue using an IWERKS system, you should comtact them if you are having problems.

A timecode reader will not do you any good on a print without timecode. I suspect that you are using an E175 that uses the TACH to start sending DTS timecode to the player.

If your print does have timecode, I highly doubt the reader has a problem. The timecode on 70mm is huge and the reader can always read it as long as the timecode is not badly damaged. Are you checking your reader's voltage?

We've released many 70mm features, some to "regular" theaters run by untrained people. We've had very few problems and most were due to the timecode being scratched off or the print's weight (such as on TITANIC) unbalancing the platters.

As mentioned, you will need to contact IWERKS and they can help you. If IWERKS gets stumped, they will contact us.

Karen at DTS
khultgren@dftsonline.com

Posted by Ivar Corceiro (Member # 1602) on 02-12-2003, 04:39 PM:

In first place thanks to all for the answers.
In fact that was an Iwerks technician who told me this timecode coudn´t be used in 8/70. I don't wanna call another Iwerks technician again, cause I´ve not a good impression about them. They´ve sold us a non-official DTS disc reader (as you can see in the image), and we are not using any sync system. We only tell to a computer to star the sound at frame number X.
One year ago we have bought a real DTS 6d to our 35 mm projector, and now i real would like to use it also in 8/70.
I work in a non-profit cinema with single theater but with two projectors (8/70 and 4/35), both Strong. Anyway, before that, I´ve worked to an americam company (AMC) in Oporto (Portugal).
This is a draw with Amazonia (the movie we are playing this year). I made it right now in Photosho just to try to show you how is our time code signal.
Thanks aain for all

Posted by Ivar Corceiro (Member # 1602) on 02-12-2003, 04:46 PM:

Sorry: Here are the images of last message...

Posted by Dave Macaulay (Member # 813) on 02-12-2003, 08:48 PM:

Are you sure the disks are actually DTS disks? There have been a few other (incompatible) systems that used CD sound - Imax certainly had/has one, maybe Iwerks has as well.
If they are real DTS format disks then you can potentially run from a shaft encoder signal. Extra stuff in the 6D might be needed (?) and you must switch the 6D over manually between encoder and reader. I'm not even sure the encoder can drive a "normal" DTS film disc or just a special disk. We have an installation in Toronto that syncs via a shaft encoder but only uses the DTS system for one film running in 48fps vistavision. I understand it will sync to the standard 35 machine (which has the normal DTS reader) but I've never switched it over personally.

Posted by Gordon McLeod (Member # 33) on 02-12-2003, 09:37 PM:

That player is the 8 channel special venue system called the 8P
get your engineer to mount a shaft encoder on the projector (If it is a Ballantyne chassis the upper feed sprocket shaft exends back enough in the back side to mount a timing belt pulley on it) and set it for 10 pulses per frame 960Hz and get a JSK timecode box and lock it to the player

Posted by Karen Hultgren (Member # 395) on 02-13-2003, 11:50 AM:

Ivar,

What you have is a DTS P8. This unit will read the TACH and play DTS discs. If you are unhappy with the P8, get a DTS-6D and 70mm reader(s) - you'll need two if you run change-overs.

Be sure all your prints have DTS timecode. If some don't, you will need to get a DTS E175 that will allow you to read TACH. The problem with TACH is that once you start, you cannot stop. If you do, you need to start from the beginnning again.

You will also need to check that all your discs are 6-track. If you have any 8-track discs, the DTS-6D cannot play them back.

I am sending you an email with information on how to contact our office in the UK. They can help you.

Karen at DTS
khultgren@dtsonline.com

Posted by Ivar Corceiro (Member # 1602) on 02-13-2003, 01:09 PM:

thanks to all

Posted by Gordon McLeod (Member # 33) on 02-13-2003, 01:50 PM:

If you use the JSK timecode box or the one from C.B. Electronics in the UK to generate SMPTE timecode they will remained locked and coast to astop and resume. I assume the player should pickup from the command of the timecode location