part two of primer written by Bruce C. Nazarian M.P.S.E.
What about optical soundtracks ?
Optical soundtracks (we mentioned them earlier). Almost all of the release formats, including the digital ones have provision for some kind of optical soundtrack, even if only as a backup. The optical soundtrack refers to the two-channel soundtrack that is carried on the optical track of the film release print.
How do I get an optical soundtrack ?
Once your surround sound format has been selected (see the paragraph below for more), you need to order an optical soundtrack negative for the film. In the case of LCRS mixes, a traditional two-channe; Printmaster track is created, and this is sent to an optical sound house for the creation of the optical negative. The optical sound house will record the soundtrack onto 35mm film using a special camera, and some will also develop their own soundtrack masters. Once the optical negative is shot and developed, it can be incorporated into your answer printing process, and a composite answer print containing your complete soundtrack can be printed or "shot" at your film lab. This usually happens during the first or second trial answer print phase.
What about
: THX - Dolby - Ultra*Stereo - DTS - SDDS?
This is a BIG question. This one point alone causes much confusion amongst filmmakers. Please take a moment and read this paragraph carefully. If you need more information after that, please contact either Gnome Productions or Magnolia Studios and we will help you out.
First, about THX.
THX [tm] is not something that you DO to your soundtrack, it is just a set of sound reproduction or mixing conditions that optimize the sound of your film's soundtrack in exhibition. Simply put, the THX standards that many dubbing stages and movie theaters adhere to are a way of being certain that "what you mix is what you get", so to speak. You may choose to mix in a stage that is THX certified, and you may not. If you do, your soundtrack should sound reasonably the same in THX theaters all around the world. It is this standardization that THX brings to the filmmaking community.
You may want to visit the THX Web Site for further information. They can be found at
http://www.thx.com/thx/thxmain.html.
To make sense out of the rest of the names, we need to know about Film (and Television) Surround Sound
Film sound tracks (and some television ones) go beyond just Left-Right Stereo; there is a Center Channel for the dialogue, and at least one "Surround Sound" channel. The Surround channel is used to project the sound out into the theater, to "surround" the audience. This is to enhance the illusion of being "in the picture". This four-channel format is called LCRS (for the Left, Center, Right and Surround channels that the soundtrack contains). Although the technical means behind this process is beyond the scope of this discussion, suffice it to say that it works well enough to have become a standard format for release prints for many years.
LCRS
You've probably already figured out that you cannot reproduce a four-channel soundtrack from a medium that only plays back two tracks. You are very right. In order to reproduce the LCRS soundtrack from a traditional film optical soundtrack (more on opticals later) you need a way to encode the channels....the Matrix
The Surround Sound Matrix Encoder (or, how to put FOUR into the space where TWO should go!)
The solution is to use an encoding device that can fold the four channels of audio down into the two channels available on the film's optical soundtrack. When the audio tracks have been processed this way, they are labeled Lt/Rt [Left Total/Right Total] in order to distinguish them from ordinary Left/Right Stereo soundtracks. The Surround Sound Matrix Encoder is a necessary piece of hardware that the audio post house must have available during your film's mix, in order to create the surround soundtrack.
The Licensing of Surround Sound formats
Now we're really getting into the heart of the matter. Dolby Labs, Ultra-Stereo Labs, DTS (Digital Theater Systems) and Sony [SDDS] all have technologies available for the encoding of film surround soundtracks into film release prints. Although these processes vary somewhat as to their method, they essentially accomplish similar things. Additionally, some of these vendors offer Digital Encoding formats (Dolby Digital, DTS and SDDS currently, and Ultra-Stereo soon to come).
The Differences in Surround Sound formats
In the most basic form, Theatrical Surround Sound consists of LCRS: Left, Center, Right, and mono Surround. A soundtrack can be encoded into this format by using a Dolby or Ultra-Stereo encoding matrix during the film's Printmastering session. DTS also has a process called DTS Stereo that can create a typical LCRS film soundtrack (check with DTS directly for more on their specific processes...).
Surround Sound formats beyond L-C-R-S:
Some of the surround sound encoding processes can create different, more complex soundtrack formats; Dolby SR/D and DTS, for example, can create six-track soundtracks for release, and Sony's SDDS is an eight-track format. In the case of six tracks, you get Left, Center, Right, Left Surround, Right Surround and a Sub-woofer channel (for enhanced low-frequency response). The split surrounds (as they are called) make it possible to move sounds around in the surround speakers, or to use stereo background sounds for even more impressive film soundtracks (Jurassic Park comes to mind, here). And if you heard Jurassic Park in a good THX theater with a DTS Digital soundtrack, you know what the sub-woofers are there for! That T-Rex really gave the sub woofers a run for their money, as well as Jeff Goldblum...Six-track sound reproduction has been with us for a while, since 70mm film releases have had the ability to deliver a six-track soundtrack that was magnetically encoded on the release print. This, unfortunately, was very expensive to produce, and problematic to control quality.
Sony's SDDS (Sony Dynamic Digital Sound) uses an eight-track delivery configuration that adds two speakers in between the Left/Center and Center/Right positions in the front speaker wall. Known variously as InterLeft, InterRight or LeftCenter and RightCenter, these channels allow for additional separation of music, effects and dialogue in the front speaker wall, while preserving the split surround format.
The Differences in Digital Sound delivery methods
The three digital systems (Dolby, DTS and SDDS) use proprietary methods to deliver the digital audio to the theater; two of these methods (Dolby, SDDS) encode the digital soundtrack onto the release print. DTS uses a different method, that of encoding a "timing stripe" onto the release print, and synchronizing a digital audio playback from an accompanying CD-ROM that carries the encoded soundtrack. In either case, the digital audio is reproduced in the theater with the same fidelity it was recorded at during the encoding process. This system neatly bypasses the traditional limitations of optical soundtracks: noise, bandwidth limitations, and headroom (transient peak) limits. Soundtracks sound cleaner, clearer and louder as a result. Please don't take this as a condemnation of optical soundtracks. A well-mixed movie can (and they still do) sound great with a well-produced optical soundtrack.
To summarize this difficult topic:
* THX specifies a set of standards that affect how sound is recorded and reproduced in a movie theater.
You get the benefits of the THX standard whenever you mix in a THX-certified mixing stage.
There is NO additional fee required.
You may display the THX logo in your film's credits if you sign a simple one-page form.
* Dolby Surround is a 4-channel optical surround format; this format is encoded in the optical soundtrack
You must license this format from Dolby Labs; There IS a license fee for this service
* Ultra-Stereo is a 4-channel optical surround format; this format is encoded in the optical soundtrack
You must license this format from Ultra-Stereo Labs; There IS a license fee for this service
* DTS is a 6-channel digitally-encoded surround format; this format is encoded on an external CD-ROM, but the timing and other information in encoded on the film release print;
You must license this format from Digital Theater Systems (DTS); There IS a license fee for this service
* Dolby Digital is a 6-channel digitally-encoded surround format; it is encoded on the film release print;
You must license this format from Dolby Labs; There IS a license fee for this service
* SDDS is an 8-channel digitally-encoded surround format; it is encoded on the film release print;
You must license this format from Sony Corporation - SDDS division; There IS a license fee for this service
I have got a video project - What's this DVD, AC-3?
relax - take a breath and we'll walk you through this...It's actually pretty simple;
Surround sound program on video materials are now released in a number of analog AND digital forms...
* Straight Left-Right Stereo program is still utilized a lot for Television, and Industrial formats...
* VHS Home video releases can be encoded in Dolby Surround (L,C,R,S), just like feature films;
* Laserdisc releases have also been using digitally encoded L,C,R,S surround formats, just like VHS
* NEW DIGITAL VIDEO RELEASE FORMATS have allowed for new DIGITAL SOUND FORMATS
o AC-3 - is a digitally-encoded surround sound format that is capable of reproducing six tracks of sound
+ Ac-3 actually refers to Dolby's Audio Compression 3 format used to compress the data
o DVD releases are also utilizing AC-3 digital sound format as well as traditional Surround Sound
All of these formats can easily be handled or prepared by a knowledgeable sound house. Please contact us if you have specific questions that you would like answered...no obligation, of course...
My mix sounded great on the mixing stage - but my print isn't in sync!
Well, we didn't say this would be EASY, just that we could help take some of the mystery out of it for you...You should IMMEDIATELY contact your post sound house and tell them what you've experienced. The Sound Supervisor on your show should be willing to take some time and help you sort this out. In the meantime, here's a few things that you can check on:
Some likely possibilities:
(1) If the Final Mix Printmaster has been transferred or copied, be sure the copy was done correctly. We have had experiences where a perfectly fine Printmaster was thrown out of sync because a copy was made first, and the optical shot from the copy;
(2) If the soundtrack DRIFTS from being in sync to gradually being more and more OUT of sync during the reel, suspect this possibility: If the Printmaster is on Multitrack tape, the SMPTE code on the tape could cause the optical soundtrack to drift in speed; If you mixed to VIDEO TAPE, a slight difference between 29.97 frame code and 30.00 frame code could throw you out of sync by many frames over 1000 film feet. If the soundtrack was shot on Mag, a mistake in running the film chain at video speed could cause the Mag to be "offspeed", just like the Multrack tape example above;
(3) If the Mag Printmaster was in sync when you reviewed the final mix, check to be sure the film lab didn't accidentally "misprint" the soundtrack by moving the optical negative a perf or two, or a frame or two when they married it to the picture. This can easily happen IF THE HEAD POP or TAIL POP is not EXACTLY CORRECT on your final Printmaster.
(4) If you printmastered in 2000-foot film reels, and FOR ANY REASON these reels were then separated and rejoined later, this poses a prime opportunity for sync to slip. If the beginning of a 2000 foot reel is in sync, and the last 1000 feet is suddenly (and consistently) out of sync until the end of the reel, suspect this phenomenon immediately.
(5) If one or two shots suddenly are out of sync but were IN sync when you mixed, ask yourself this: did you mix from an Avid or Lightworks (or other electronic edit system) output? If so, it's possible the film negative was not cut to the exact same shot length as the electronic output; Have you verified the length of all optical effects? If you have inserted optical effects, they may not have been counted exactly right, and you may have gained (or lost) a perf or frame or two in the effect; either way, your soundtrack will lose sync right then and there, and STAY out of sync for the rest of the reel (unless another optical effect error magically puts it back in sync again!)
(6) Finally, when all else fails, it is remotely possible that the optical negative might be offspeed. A quick call to the optical sound house will help them verify this for you.
My foreign distributor says I need an "Emenee" to make a sale ?
Actually, it's an "M and E" or "M&E". This element comprises the "MUSIC and EFFECTS" elements of your original soundtrack, with ALL of the English language dialogue and Walla removed to allow for foreign language dubbing. In most contemporary post sound packages, an "M&E" is allowed for in the original bid. This process requires preparation during the original sound editing, as well as some additional Foley coverage that might NOT be needed for a straight domestic release. If you NEED an M&E, be sure that you tell your post sound house that UP FRONT. It WILL add some dollars to your post bid, but you WILL want it, if you are to have any possibility of a foreign release or sale at all. Preparing this element NOW will buy you plenty of "peace of mind" later on. The M&E can be on Mag, on DA-88, on DAT, or on almost any format that can be synchronized. It DOES NOT need to be converted to an Optical soundtrack form at this time...only later, when a new foreign Printmaster is created after the foreign language has been added to it.
Do I need to know about the academy rolloff ?
Well, although it is a holdover from film sound's infancy, we need to be aware of it, since it does have some relevance in certain circumstances. The academy rolloff is a specific frequency response curve that is used in dubbing stages to simulate the effect that the old-time optical soundtrack would have on the frequency of the final soundtrack. With advances in technology in today's film industry, its use is diminishing, although it has been used on mono theatrical trailers to this day.
cheers
geo