A film’s first shot, its first image, is one that’s obsessed over by many directors. But how many put as much care into its first sound? Francis Ford Coppola did, along with sound designer Walter Murch, when constructing the opening of Apocalypse Now. The famous helicopter sounds actually enter over black — they are the first input of any kind an audience member receives. And, of course, those weren’t just any helicopter sounds. In the video above — a section of a documentary commissioned for the Paramount 2006 home video release and made by Zoetrope’s former head of post, Kim Aubry, and editor Serena Warner — sound rerecordist Richard Beggs and post-production sound recordist Randy Thom illustrate the ambitious use of the helicopter effects within the film’s 5.1 mix. Check out Murch’s hand-drawn diagrams about just now those effects are sequenced and mixed.

In 2000, Murch spoke to Michael Sragow in Salon about Apocalypse Now‘s sound design. They began by discussing those helicopters. Here’s Murch:

There was a lot of discussion between George [Lucas, the original director] and me, and between us and John Milius, who was writing the script, that what made Vietnam different and unique was that it was the helicopter war. Helicopters occupied the same place in this war that the cavalry used to. The last time the cavalry was used was in World War I, which demonstrated that it didn’t work anymore. In World War II there was no cavalry. Then we got the cavalry back, with helicopters, to a certain extent in the Korean War, and really got it back in the Vietnam War. The helicopters were the horses of the sky — the whole “Valkyrie” idea came out of that discussion. And, of course, we thought of the four horsemen of the Apocalypse. The cavalry-horsemen-Apocalypse thing was bred in the bones of the project.

And here Murch discusses how the electronic helicopter sounds meshed with the decision to mix in 5.1.:

But Francis made the decision to make this film quadraphonic [or quintaphonic]. Essentially the format we established for Apocalypse Now is now the standard for DVD and any big Dolby Stereo film: three channels in the front and then two channels in the rear and then subwoofers. And helicopters are ideally suited to that, because they fly and move around and hover. So it’s a perfect format for a helicopter movie, compared to, say, a submarine movie, or a boat movie, or an airplane movie. Helicopters can position themselves and swoop and go in circles; they are kind of circular beings.

I think people were impressed because there was this whole new way of listening to movies and it matched the main aural subjects, which were helicopters. Then you had the fact that the film is told from a particular person’s point of view, that it presents the war as seen by Captain Benjamin Willard. And we establish right from the start that the helicopter sound is part of what makes you identify with Willard — it subjectivizes your experience, so it’s not just an impressive technical sound, it’s got a psychic dimension that is very deep. So you have all this working at different levels at the same time. Some of it was deliberately investigated right from the beginning, even when there was a different director, so it was inherent in the script. But a lot of it was also discovered in the process of making the film.

A detailed account of the film’s mix can be found at Mix, with these paragraphs describing the organizational math required to keep track of all the tracks given the technology of the time:

Because their effects premixes were a quilt of many different colors, with speaker assignments changing constantly, the Apocalypse mix crew had to keep detailed notes as to what elements were occupying a track at any given moment. For example, on reel 6 (the second part of the helicopter attack), effects premix 1 contains Foley, fire, surf, PBR (Patrol Boats, River: the type of boat the crew is on) and verts. (“Verts” was Murch’s term for “vertical effects,” which are essentially one-off events, as opposed to “horizontal” effects that occur throughout the film, such as backgrounds, PBR and helicopters. To bring a flow and consistency of style, sound editors were assigned specific elements instead of doing everything for a given reel, the then-standard practice in Hollywood.)

Higher math shows that neither the board nor the machine room would allow for all premixes dialog, music and effects to be hung at the final mix. The solution lay in dubbing the five effects premixes into one or two 6-track effects “combines,” while the near-final music, dialog and narration were playing on the small faders through the monitor only, having themselves been regrouped to 2-inch to free up the dubbers. A similar technique was used during music premixing, with dialog and effects combines or premixes playing in the monitor while music was folded down from multitrack to 6-track mag.

The engineering staff at Zoetrope, which was at that time headed by Wayne Wagner, performed extensive modifications on the console to adapt it for film mixing, among them retrofitting the MCI automation with four “quad” joysticks. All four could be used if only four quadrants (left/center/right/mono surround, or left/right/left-surround/right-surround) were needed. If 5-channel panning was desired, then two joysticks were used in series. The first panned through left, center and right, with the fourth quadrant feeding the second joystick, two of whose outputs were assigned to left- and right-surrounds. Automation data for Apocalypse was recorded on a separate piece of 3-track mag, bouncing between tracks. (An early investigation to record the data on hard drives came up with a $10,000 estimate!)