Post Scripts
Adding Flexibility to the Final Mix
By Dane Davis

The audience hears what humans don’t hear in The Forgotten.
Recent evolutionary leaps in the process of post production have created a need for increased flexibility in sound design as well. Sound designers need to respond to an increasingly fluid workflow: Whole sequences now come from visual effects developers, with an infinite number of internal timing and content changes that don’t register as “picture changes” to anyone but the unfortunate sound editors. This shift is accompanied by higher expectations from film and TV clients in terms of both aesthetics and speed. In short, today’s compressed final mixing schedules require more and more procedural efficiency from those of us working on this side of the theater speakers.

In previous columns, I surveyed the past challenges of building mag units and loading twenty-two track blocks of units on tape into the faders, and the more recent introduction of delivering work in workstation sessions. As practical considerations and artistic intentions lead sound designers to shape tracks farther in advance of the formal re-recording stage, the corresponding challenge is to minimize the degree to which re-recording mixers are trapped by decisions made by sound editors. Sound editors could inadvertently cause problems for the mixing crew by making changes in volume or positioning, or in the audio material itself.

The “alien consciousness” sound design evolved
in a massive Pro Tools session with various degrees
of pre-balancing and panning of layers
in The Forgotten.
Some interesting solutions have emerged through attempts to avoid those problems. For example, some sound designers do live editing in bench tracks and then move them into “hot” tracks that feed the board faders only after the mixer has been informed of the new or altered material. Other crews have put a digital multitrack recorder between the workstation and the console. This machine stays in record mode all the time — unless a sound editor is making a change, at which time the channel in question is taken out of record so it becomes a playback dubber for that track. When the work is finished, the board is fed directly from the editor’s track again (through the “E to E” of the recorder in the middle). This solution works well, until the number of sweetener tracks (those that are being added to or changed) grows too large to manage with the intermediary hardware. When mixing very complicated, visual effects-laden movies, there are often dozens of added tracks feeding into the big board by the end of the project.

A less hardware-intensive approach is to edit new material on an offline Pro Tools system. When the tracks are ready, they are imported into the online system feeding the console. The material is then dragged into tracks that the mixer can route to the input module.

Feeding various formats of sound design into
the final mixing board on The Forgotten.
An alternative is to wire the digital output from the offline Pro Tools system into the online system and record the new material into tracks of the feeding workstation. If the section of added sound is short, this process can be fairly quick (especially if recorded on the fly, as the room moves forward through the section in question). Nevertheless, this approach has the obvious disadvantage of lacking any virtual control, because the tracks have been “hardened” into flat regions with no extensions or alternative material under the edits. If this new audio needs to be altered in anything but the most basic way, the editor needs to go back to the other machine, make the changes in the virtual tracks, and transfer that section again in real time. The need to maintain the maximum degree of control up to the latest possible moment drives the current move toward total virtual control and integration.

The model of the smaller, self-contained single-session mix, where every sound remains completely alterable, sets the stage for the near future of huge film mixes that combine thousands of tracks from various sources. The current necessity of pre-combining tracks in a fixed, unalterable way can be left behind once the number of simultaneously voiceable tracks becomes commensurate with the number of contributing sound elements.

Brave cave divers ride underwater scooters a mile underground
in The Cave.
It’s increasingly difficult to find the time to balance, pan, and EQ finished work while also pre-mixing dialog, ADR, Foley, backgrounds, and sound effects on a large stage. Many sound designers are bringing complex sessions to the final stage — sessions that include all the shaping required in a 5.1 environment. When the final mix room passes each section, the Pro Tools tracks are mixed from all of the source tracks, according to the local automation of faders, panners, and plug-ins through 5.1 output groups that patch into the main board. By sending each group to its own 5.1 bus terminating in a 5.1 auxiliary return, the external connection engineering is minimal, and a master fader for that group is already established. With spatial positioning, perspective shifting, and even room reverberation already built in, these sessions appear to the final mixer as if they were “hard” pre-dubs made on a conventional stage, incorporating the talents and the limitations of the person making them.

The fundamental difference is that most, if not all, of the decisions that have already been made in a virtual pre-mix can now be altered (if necessary) to accommodate the final environment, including the finished dialog/ADR mix, the score, source music, and the ever-changing visual image. Ideally, enough massively voiced Pro Tools sessions can supply all of the pre-mixes in this type of finished — but “soft” — form. On conventional stages with gigantic consoles, the mixer must also have a “sidecar” console between the board and the Pro Tools virtual console to access the session automation. The alternative is to require sound designers/editors to make changes on the contributing Pro Tools system to use local monitoring (difficult in 5.1) or the house speaker system. This is a less-than-ideal overlap of labor, but it is happening all the time in this present transitional era.

In The Cave, all pre-mixes except the dialog
were created in Pro Tools, including this 5.1
virtual pre-mix of underwater scooter sounds.
Because the automation systems in large conventional mixing consoles and editing workstations remain completely incompatible, the workflow continues to disconnect between the off-stage main stage mixing work, even though the operations are identical. An additional factor in favor of merging the camps is that dubbing mixers increasingly have to edit their automation as the picture editing process continues, right through the final mix process. Hundreds of edits sometimes have to be made in each reel, across every single track of automation. This edited automation then needs to be checked and “patched,” exactly as sound editors must re-edit after mathematically conforming tracks. Without seeing the automation as a block, it’s difficult to convert the less-than-obvious change notes into intelligently conformed mixing data.

As editing workstation–based mixing consoles evolve and approach the capabilities of existing large consoles, this clog in the workflow should dissolve. In seems inevitable that the mixing desk of the future will be able to see and include all previously created automation from a large number of independent editorial and pre-mix sessions. The recent appearance of the Digidesign ICON environment on small and medium-size re-recording stages shows us the not-so-distant future of the art. As conventionally trained and experienced dubbing mixers adapt to this somewhat new way of thinking, big-time film mixers will benefit from the increased efficiency and smoothness of this new audio post model. There are still important improvements to be made in the new model — and the best conventional consoles are still better able to handle things like rapid, precise, and updatable 5.1 panning to picture — but progress has been very swift in the last few years. It is an exciting time to experience the joining of different sound teams at the final stage, in ways never thought possible — or necessary — a few years ago.