IN7OMM.COM
Search page
Deutsch | Language
7OMM e-News
Rumour Mill
Contact | Volunteers

WHAT'S ON IN 7OMM?
Todd-AO Festival
KRRR! 70mm Seminar
Widescreen Weekend
7OMM Festival
 

7OMM FILM
"Flying Clipper"
"The Hateful Eight"
"The Master"
"Oklahoma!"
"Scent of Mystery"
"2OO1"

IN LARGE FORMAT
Todd-AO
Ultra Panavision 70
Super Panavision 70
Dimension 150
DEFA 70
Sovscope 70
Technirama
IMAX
Showscan
Cinerama
Cinemiracle
70mm Blow-up

NEWS
2016 | 2015 | 2014
2013 | 2012 | 2011
2010 | 2009 | 2008
2007 | 2006 | 2005
2004 | 2003 | 2002

LIBRARY
Interview & People
Cinemas
DP70 / Norelco AAII
70mm Projectors
Rama Galore
Cinerama Remaster
70mm Engagements
SENSURROUND
Stories
Remember

THE 7OMM NEWSLETTER
2005 | 2004 | 2002
2001 | 2000 | 1999
1998 | 1997 | 1996
1995 | 1994 | PDF
 

in70mm.com Mission:
• To record the history of the large format movies and the 70mm cinemas as remembered by the people who worked with the films. Both during making and during running the films in projection rooms and as the audience, looking at the curved screen.
in70mm.com, a unique internet based magazine, with articles about 70mm cinemas, 70mm people, 70mm films, 70mm sound, 70mm film credits, 70mm history and 70mm technology. Readers and fans of 70mm are always welcome to contribute.

Disclaimer | Updates
Support us
Testimonials
Table of Content
 

eXTReMe Tracker
Extracts and longer parts of in70mm.com may be reprinted with the written permission from the editor.
Copyright ę 1800 - 2070. All rights reserved.

Visit biografmuseet.dk about Danish cinemas

 

Implementation of a Proposed 9-Channel (8.1) Sound format for 70mm, 35mm and D-Cinema

Read more at
in70mm.com
The 70mm Newsletter
Written by: Ramon Lamarca Marques, Brian Guckian and Mike Taylor Date: 16.01.2008
This article posits a concept for the practical application of a new 9-channel (8.1) sound format across 70mm and other theatrical exhibition platforms. It builds on and enhances existing techniques used to deliver multi-channel sound in the cinema, in a cost-effective and realistic manner, and with a greater degree of differentiation to home entertainment formats.
 
More in 70mm reading:

65/70mm Workshop


Internet link:
 

Background

 
The conventional 5.1 sound format used both for theatrical and home cinema works very well in terms of providing stereo stage channels with a discrete centre, coupled with stereo surrounds and a separate sub-woofer. This format has been very effective in dramatically improving the audio experience in the cinema and home viewing environments, and in recent years has been refined with the addition of a back (or rear) surround channel.

However, 5.1 is of course not the only multi-channel sound format that has been developed for theatrical use, and in large theatres, the advantages of 5 stage channels, with additional Left Extra and Right Extra information, and a Centre that can be kept free from music and effects, have been known since its advent with Cinerama in 1952. The "5 across" configuration gives a far better spatial audio experience in large theatres, as the additional Left Extra and Right Extra channels fill the aural "holes" between the Left and Centre and Right and Centre screen channels for very wide screens. The "5 across" configuration has also been used on several 35mm SDDS releases over the years, and many theatres are equipped for this configuration.

What this article does is to propose, for large screens, a marriage of the traditional "5 across" format with the current enhanced 5.1 format with rear surround, to yield Left, Left Extra, Centre, Right Extra, Right, Left Surround, Right Surround, Back Surround and Sub-woofer channels. This gives a total of 8.1, or in short, 9 channels, with several advantages that will be outlined.
 
 

Practical Application

 
Click image to see enlargement

Adoption of any new sound format in the cinema is dependent on ease of application and ubiquity. It is important that any format be applicable across a range of theatrical release formats to be viable. For instance, it is highly unlikely that mixing time could be allocated affordably to make a 9-channel mix purely for 70mm purposes.

Happily, a 9-channel format can theoretically be accommodated for 70mm digital, 35mm digital and D-Cinema sound formats, which is ideal in today's sound post-production and re-recording environment. Indeed there is very little difference between mixing for 9 channels instead of 8 (as has been done up to now on selected releases); the only addition being the Back Surround channel, which in any case is often provided for when doing mixes for 35mm and home cinema.
 
 

Hardware

 
Many theatres are already equipped for both "5 across" and Back Surround playback, the only point to note being that both have not been formally used together up to now. Adaptation in these cases to play back formal 9-channel material does not require new speaker runs, speaker assemblies or amplifiers; rather modifications would be made only at the processor end of the system.

This would require manufacturers whose products are theoretically capable of playing back up to 10 channels of audio to offer a hardware upgrade via new cards, outboard units, etc. It is not within the scope of this article to detail exactly how this could be done, but merely to point out that it should be possible and is worthy of consideration. 70mm audio and certain 35mm audio formats are theoretically upgradeable to 10-channel reproduction, whilst D-Cinema accepts up to 16 channels via the DCI specification.
 
 

Mixing and Playback Processes

 
The proposed 9-channel layout is shown in the diagram. Since a 9-channel mix must also be reproduceable in a 5.1 theatre, processors would have to include a "fold-down" function so that the Left Extra, Right Extra and Back Surround channels could be mixed into the 5.1 "envelope" on playback.

This is already done in 5.1 theatres equipped to play back 8-channel mixes in the 5.1 format; in this case the Left Extra and Right Extra channels are apportioned to the Left and Centre and Right and Centre channels, respectively. The Back Surround channel is then simply not reproduced, or if this is problematic then a method of apportioning the Back Surround information between the Left surround and Right Surround channels would have to be found, possibly via another "fold-down" function in the processor.

Cinemas with 5.1 reproduction only may find it economically beneficial to convert one or two large screens to the 9-channel format if this is done at the same time as, for example, a D-Cinema installation. Two-screen capability is advantageous so that films can be transferred after their opening run.

A final consideration is archivability of 9-channel mixes. Happily, it is possible to record up to 10 tracks of audio to 35mm fullcoat mag using the specialised "8+2" head and track configuration. This uses 8 sound records across the the mag between the perforations, with the two additional tracks outside the perforations, on each side of the mag film.
 
 

Advantages of a 9-Channel Sound Format

 
Adoption of 9 channels as a new choice for mixing and theatrical reproduction gives the following advantages:

- Superior spatial reproduction across the large screens increasingly used in multiplex and other cinemas;

- Excellent dialogue clarity as the Centre channel can be kept free of Music and Effects;

- All the advantages of three Surround channels as found on selected 35mm releases;

- Enhanced enjoyment for audiences, with greater artistic possibilities and quality;

- Applicable across 70mm, 35mm and D-Cinema formats, making economic sense;

- Relatively easy to implement whilst not precluding addition of more channels in the future;

- Theatrical format only, providing greater differentiation to the increasingly sophisticated home cinema offering and thus encouraging audiences to choose the theatrical cinema option;

- Facilitates increased use of the 70mm format for limited "roadshow" style engagements of "tentpole" releases.
 
 

Conclusion

 
The advantages and practicality of a 9-channel sound format for 70mm, 35mm and D-Cinema theatrical release platforms have been outlined. Feedback on this article is welcomed; please contact the Workshop Editors.
 
 
 
Go: back - top - back issues - news index
Updated 22-12-16