|
This topic comprises 4 pages: 1 2 3 4
|
Author
|
Topic: Optical track matrixing.
|
Tim Reed
Better Projection Pays
![](/ubbmembers/137h.jpg)
Posts: 5246
From: Northampton, PA
Registered: Sep 1999
|
posted 10-17-2002 09:56 AM
Any movie sound mixers on the forum? I have a question.What condition delivers a good solid center channel signal on the optical track? Here's my understanding of the Dolby/Sansui 2:4 matrixing scheme, as used on movie optical soundtracks. A signal appears on one of the two optical tracks. That sound is reproduced from the left (or right, as the case may be) channel only. When the same signal appears on the opposite track (only), the sound is reproduced from the other side of the screen. When on both, in phase, it comes from the center. My question has to do with the level of this center signal ON THE FILM, as compared to individual striations of L-only or R-only signals. What are the optical track conditions that reproduce the center channel in the theatre, to the same level as a lone individual track (L or R-only) would at the screen? Is there something in the encoding that raises the level or modulation of the L and R striations of the optical track that specifically steer it to the center channel? Here's what I am observing. I have a track with two equal (in phase) signals which seems to come, not from the center channel in the theatre, but from the left and right speakers simultaneously. This isn't a reproducer or processor problem, it's a print master recording condition that I'm researching. Thanks! ------------------ Better Projection Pays!
| IP: Logged
|
|
|
|
|
Tim Reed
Better Projection Pays
![](/ubbmembers/137h.jpg)
Posts: 5246
From: Northampton, PA
Registered: Sep 1999
|
posted 10-17-2002 11:50 AM
Thanks, guys, for the quick responses. It's not a theatre problem, it's the print master.Gordon, does the .7 value refer to 70% below a L-only / R-only signal? That would explain why the sound appears to eminate from L and R simultaneously as it stands. Thanks again! -Tim ------------------ Better Projection Pays!
| IP: Logged
|
|
|
|
|
|
|
|
Tim Reed
Better Projection Pays
![](/ubbmembers/137h.jpg)
Posts: 5246
From: Northampton, PA
Registered: Sep 1999
|
posted 10-19-2002 01:02 PM
The print master wasn't created properly. It is a 2:4-channel track, but the parts that were supposed to be hard center sounded like they were coming from L and R. Left is left, right is right, and the surround worked great. Center just wasn't very well defined. The problem was noticed in an answer print. ![](http://www.film-tech.com/ubb/wink.gif) ------------------ Better Projection Pays!
| IP: Logged
|
|
|
Scott Norwood
Film God
![](http://www.film-tech.com/ubbmembers/30f.jpg)
Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99
|
posted 10-19-2002 05:08 PM
I, too, am curious about the printmaster formats on the CP-500:26 - printmaster 2-ch. no NR 27 - printmaster 2-ch. a-type 28 - printmaster 2-ch. SR I had always assumed that these formats were intended for 35mm mag tracks to be played through an external preamp (MPU-1, perhaps) and then fed through the matrix/eq/output and, optionally, the NR stages in the processor. Thus, the only difference between, say, 27 and 04 (Dolby A-type) would be the input source (external mag. vs. optical preamp), correct? Or is there more to it than this?
| IP: Logged
|
|
|
|
All times are Central (GMT -6:00)
|
This topic comprises 4 pages: 1 2 3 4
|
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2
The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion
and agrees to release the authors from any and all liability.
|