This is topic Processors used for 70mm mag Dolby Stereo SR in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=008318

Posted by Robert Minichino (Member # 3495) on 10-19-2006, 11:33 AM:
 
I'm curious as to what processors were used for the Dolby SR 70mm mag tracks, particularly SR Split-Surround (Format 46). All the Dolby processors I see only offer SR decoding for optical, but I assume cards were switched on the CP200 aux rack for 70 mag SR? The Panastereo 70mm processor seems to be able to support it, but it seems newer and it's rather expensive. I eventually want to support all 70mm mag formats that are likely to be on a repertory print, which means supporting SR, even if we don't have split-surround.

What were some common processor configurations in the day for 70mm mag SR?
 
Posted by Richard May (Member # 2627) on 10-19-2006, 12:08 PM:
 
Yes, the cat 22 cards were switched with SR cards on the CP200.
 
Posted by Martin Brooks (Member # 1269) on 10-19-2006, 08:52 PM:
 
My records show that there were only eight possible 70mm films that were recorded in SR and all but the first one (which was an experiment) are questionable as to whether they were actually released in SR, so if my information is accurate, I wouldn't go nuts trying to get SR if it's only for mag. You would, of course, want it for analog.
 
Posted by Gordon McLeod (Member # 33) on 10-19-2006, 09:13 PM:
 
There were several SR 70mm prints
LOA was SR up here as was some of the star treck films
Somewhere I have a list of titles that the toronto prints were SR for
But in most cases the cat22 were swapped with cat 280t except at one locations where 3 DOLBY cat363 with cat 300 a/sr cards were installed instead of the internal cat 22 and they were format switched
 
Posted by Michael Coate (Member # 757) on 10-20-2006, 12:11 AM:
 
quote: Martin Brooks
My records show that there were only eight possible 70mm films that were recorded in SR and all but the first one (which was an experiment) are questionable as to whether they were actually released in SR
Eight? Are you kidding? I'm aware of at least 17.

How would you define "released"?
 
Posted by Steve Guttag (Member # 268) on 10-20-2006, 03:07 AM:
 
Starting with the restoration of Lawrence of Arabia...every 70mm magnetic film I handled had SR noise reduction. It is also reasonable to presume that any reissue that uses striped media (not as far fetched as it sounds since it will be a low production print and would probably be cheaper to stripe a few prints than to create the DTS negative for just a few prints) would also be SR encoded.

We have installed the full Panastereo CSP1200/4600 system with SR and A for 70mm and we have also done the CP200 thing with a physical change out of the NR cards for SR. My next CP200 installation will have SR noise reduction available via format selection though.

Steve
 
Posted by Robert Minichino (Member # 3495) on 10-20-2006, 11:38 AM:
 
There are a few desirable prints that are in SR, so the capability is important.

I was thinking about the 363 but the expense and having to mod the CP200 made me think it wasn't so common, so thanks for confirming my suspicions there.

Considering expense, swapping Cat 280s into the CP200 looks like the best bet unless we happen to run across a cheap trio of 363s or an SRP-24 [Big Grin] I'd like the Panastereo, but the budget isn't there, especially considering the frequency we'd probably run 70mm mag anyway.

EDIT: I was also confused because I forgot about the P/Q channels in the CP200 aux rack for split-surround.
 
Posted by Louis Bornwasser (Member # 3063) on 10-21-2006, 08:32 AM:
 
You have to consider the odds of getting an SR print.....slight. The other 99.9% were "A."

Remember that MAG was pretty good even with no Dolby. Dolby A helped a bit more. SR (although I am a big SR fan) was really not needed much on 70mm.

One problem with determining "what to do" is that EVERY format was possible on MAG since prints could easily be resounded, even for an individual theatre. Now realize that reels are swapped routinely on old prints and that the exchanges are not aware of "non=physical" differences.

My personal feeling is that, unless you are an archive, a "fully equipped" CP-65 would be more than adequate, especially considering what the studios of the time were like. Louis
 
Posted by Gordon McLeod (Member # 33) on 10-21-2006, 12:25 PM:
 
I tend to disagree with the feeling that the proper NR is non essential
A 6 track SR print playing without SR is very annoying
 
Posted by Louis Bornwasser (Member # 3063) on 10-21-2006, 10:08 PM:
 
Proper nr is essential to proper playback, if so encoded.

NR at all does not add as much to the quality of 70mm MAG as it does to a lesser quality medium, such as optical. Louis
 
Posted by Gordon McLeod (Member # 33) on 10-22-2006, 12:05 PM:
 
A SR 70mm print sounds better than a SRD print [Smile]
 
Posted by Steve Guttag (Member # 268) on 10-22-2006, 02:18 PM:
 
I must say...I think I disagree with just about all that Louis has posted on this thread...

That is, the CP65 should not be used for 70mm and should never have been 70mm "capable." By the time that the CP65 came out virtually all 70mm releases were in SR. Any new or newer 70mm prints that will be or have been struck use SR for the noise reduction further making the CP65 a very poor choice. The CP65 also has a near worthless EQ for the surrounds. The CP65 should stick to what it is best at...Optical stereo and digital with either a DA20 or DTS processor (and I recommend outboard EQ for the aforementioned surrounds).

Next on the hit parade...70mm absolutely benefited from noise reduction. Anyone that runs "conventional" magnetic films knows the instant that they start the ever prevelent Hisssssss coming from the surrounds and the occasional hum from mag lines/heads being near something they should not. Dolby A NR address the hiss very effectively. An arguement could be made about SR's benefit over A for 70mm magnetic. In truth, the potential benefit would come from the ability to increase the dynamic range. The best 70mm track I've ever heard (in terms of clean/clear, and great dynamic range...both loud and quiet) was True Lies and it was in SR.

The Dolby CP200 is the 70mm processor of all time, period, bar none! I've installed the Panastereo CSP1200/4600 combination and they are good and have the potential for a very quiet and clean system but the CSP4600 is clearly an add-on so there are some quirks to work around. The CSP4600 also does not properly play back conventional pre-NR films since it does not apply a form of the Academy filter to the signal to offset the fact that the B-Chain has been EQed for a flat response. The original tracks were mixed to the rooms of the day, not the rooms of TOday. As such, they will sound overly bright and you will hear the various tracks gating on and off. That same track played back on the CP200 will sound much more natural and will mask the gating. Then again, Ray Derrick worked with me on modifying a CSP4600 preamp card to allow for adjusting in an "Academy" type filter and the results were VERY impressive...in fact, it is the closest thing to Louis' statement about 70mm not needing any NR...the CSP4600/1200 played an old track of 1957 in a very natural way that was quite educational.

Steve
 
Posted by Mark Gulbrandsen (Member # 72) on 10-22-2006, 07:33 PM:
 
quote: Steve Guttag
The best 70mm track I've ever heard (in terms of clean/clear, and great dynamic range...both loud and quiet) was True Lies and it was in SR.

Its also the best optical SR track I've ever heard. It even blew away people from THX there were in town to open a new theater.

Mark
 
Posted by System Notices (Member # 2357) on 02-13-2011, 04:45 PM:
 

It has been 1574 days since the last post.


 
Posted by Ben Wales (Member # 92) on 02-13-2011, 04:45 PM:
 
quote: Gordon McLeod
But in most cases the cat22 were swapped with cat 280t except at one locations where 3 DOLBY cat363 with cat 300 a/sr cards were installed instead of the internal cat 22 and they were format switched
I know it is a "Old" topic, but would like to ask what are the mode switch settings on the Cat280T SR cards and any other set up info required to playback 70mm Dolby SR on a CP200?.
 
Posted by Steve Guttag (Member # 268) on 02-13-2011, 06:38 PM:
 
It is irrelevant in a CP200 with a Cat 280T. The mode switch is not used. Just be sure that it IS a "T" version though (has the special cover that says "T" or has the sticker on it. If not, check link "A" near the edge connector...if it is there...snip it.

-Steve
 




Powered by Infopop Corporation
UBB.classicTM 6.3.1.2