Picture gives information, but sound brings emotion, so your documentary needs a bold sound design and good, clean location sound as a foundation. Some sound theory and knowledge of basic equipment, as well as practice and a critical ear, will help you achieve this.
Unfortunately for sound recordists, documentary film shoots can’t always accommodate their needs. In transparent filmmaking, microphones must stay out of sight and recordists adapt as best they can to the needs of the scene. The director can help by stabilizing speakers during a dialogue sequence or by concealing a useful microphone in that nice potted plant on the dining room table. Most of all, he or she can help by appreciating what is involved in sound acquisition and the pain recordists suffer when they can’t always turn in first-rate work.
Imagine hitting a bunch of billiard balls; some go into the intended pocket, others ricochet off the cushions before finding their way into pockets. This illustrates the behavior of sound when you record a voice in a moderately sound-reflective room. The voice is signal and what accompanies it is reflected or reverberant sound (Figure 11-1). That is, some of the voice goes straight to the microphone, but some of it radiates outward and bounces off the floor, ceiling, walls, and that table in front of the speaker before reaching the mike. Reverb sound, making a longer journey, arrives fractionally later. Direct and reverb sound then combine at the microphone to muddy the clarity of the original. People think, “Oh, let’s fix it in the sound mix,” but once combined, sounds are no more separable than the eggs in an omelet.
In Figure 11-1, a person sits in a room talking to camera. The microphone is picking up not just signal and reverb but also background presence or ambient sound. Also called atmosphere, it might include distant traffic, the hum of a refrigerator, a dog barking, or in summer the whir of air conditioning. Ideal dialogue recordings have lots of signal (what you want) and very little noise (everything else). The world is not ideal for sound recordists, but there’s always something you can do to improve matters. That mike in Figure 11-1 could go a lot closer to the speaker. Moving it won’t affect ambience or reverb levels much, but it will dramatically raise the direct signal level in relation to them. For this reason, avoid using a deck mike (one mounted on the camera) if you can work with a partner using a boom or fishpole to get the mike in close (Figure 11-2). Reasons to abandon the deck mike are:
Location sound always has three main elements: (1) signal, (2) reverberation, and (3) ambience. The record-isttries to maximize signal while minimizing reverb and ambience. These can always be added later, but not subtracted.
We’ll look at boom handling techniques a little later.
On-axis sound (also called on-mike sound) is sound arriving down the mike’s most receptive axis. Off-axis or off-mike sound arrives from other axes. Directional mikes favor on-axis sound and discriminate against that arriving off-axis. Most of the reverb and ambience in Figure 11-1 arrives off-axis, so the right mike can discriminate against them.
Sound perspective is the aural sensation of changing distances when a sound source (person, helicopter, horse) moves around.
A resonant space is one that has a note to which the room spontaneously resonates. You’ll know this from singing in your shower and finding a frequency at which the room starts ringing and augmenting your voice. Resonances and sound reflectivity are bad news to sound recordists, as are noisy locations.
Recordists test the acoustics of any recording space on entering by making a single loud hand clap and then listening critically to its aftermath. The space is either live (echoey) or dead (sound absorbent). The latter is nearly always preferable.
If you record someone speaking in a large, sound-insulated, carpeted room with heavy drapery, then you will have an excellent signal-to-noise ratio. Record that person in a medium-sized bathroom, with tiled walls and floor and no soft furnishings, and you’ll have a dreadful S:N ratio. In postproduction, you can always add atmosphere or reverb to a clean recording, but only under special circumstances can you subtract noise commingled with signal.
Speech-based filmmaking, therefore, calls for careful recording. Recordists aim to:
The improvised nature of many documentary conditions often confounds these aims. Imagine you’re filming your main character working out at a noisy health club, and this is where he chooses to tell you what’s breaking his heart. Or he embarks on something just as important in a rattly truck cab. When your subjects are restless teenagers, staying on-axis gets difficult. Because the camera must have different shots to cover a sequence, the recordist must make fast mike position changes. The recordist must either adapt or appear momentarily onscreen with that deer-in-the-headlights expression.
Once you edit sound together, inequities become glaringly apparent. Adjusting playback levels can even out a speaker’s voice level from angle to angle, but that leaves you with varying ambience levels at each sound cut. In postproduction, you can ameliorate these by loading up the quieter tracks with ambience, but the net result is, of course, more noise.
During production, reduce reverb by:
Professional mikes use balanced line cables with sturdy XLR connectors that lock into their sockets, and they use noise-canceling three-wire connections between mike and recorder (Figure 11-3). With these you can use 10- to 20-foot or longer microphone cables without picking up electrical interference. Consumer equipment uses the two-wire or unbalanced sound connections, easily identifiable by their two-contact jack plugs (Figure 11-4). These allow only short cable runs before noise and interference set in. Also, because mini-jack sockets are attached to camcorder circuit boards, a single yank on the cord can do untold damage. Even in kinder circumstances, jack sockets quickly become unreliable unless you provide cable strain relief. This means anchoring the headphone or mike cable to the camera body so handling stresses do not reach the plug or its socket (Figure 11-5).
Whenever possible, set sound levels manually. This means, during a test, lowering the recording level as it registers on the volume unit (VU) meter or bar graph until no peak sound surpasses, say,–6 decibels. Check what your camcorder manual recommends and make test recordings of loud transient sounds such as hand claps or door slams to pinpoint the threshold where distortion sets in.
In the typical stereo VU meters in Figure 11-6, the numbers run counterintuitively from minus to plus quantities. Low sound levels register as high minus decibel (dB) numbers. Then as sound levels rise, the safe or sound saturation point peaks at 0 dB. Beyond that you enter the red or danger zone of + dB levels where distortion can ruin the recording. Here beginneth wailing and gnashing of teeth.
Analog sound—the precursor to digital recording—was quite forgiving during overloads, but peaks beyond 0 dB in digital recording usually distort badly. Be aware that unless your equipment has a peak reading meter, your VU meter is averaging incoming signals and thus hiding the awful truth from the unsuspecting user. By the time you’ve seen the peak red light come on, the damage is done. To guard against this, set levels for averaging meters to peak at–6 dB.
Using automatic sound-level spares you distortion, but during long gaps in an oral memoir, for example, the recording level may hunt—that is, record at louder and louder levels until your subject speaks again. The reason is that electronic circuitry has zero intelligence and does its job strictly according to level. Use automatic level whenever you are in a chaotic situation with soft sound punctuated by, say, door slams, screaming revelers, or other loud and transient peaks.
If your camcorder has a single mini-jack mike input, add one of the excellent proprietary input boxes (Figure 11-7). Because it is clamped under the camera body, the box and its beefy XLR sockets safely absorb the inevitable cable-handling stresses. Now you can plug in two balanced-line microphones and even adjust each for level. As the illustration shows, the box’s output plugs into the camcorder mike input using a stereo (three-connector) mini-plug on a pigtail lead. Be aware that condenser microphones—in particular, shotgun mikes—either run on inbuilt batteries or draw current from phantom power supplied by some (but by no means all) camcorders and input adapter boxes. Phantom power is not as exciting it sounds. It’s a tiny current at 48 volts fed to the mike through two legs of its three-wire cable.
Virtually all camcorders have stereo (two-track) recording capability and can accommodate two inputs. If yours makes recordings that are well separated, then you can record, say, two people each wearing a lavalier (chest) microphone and end up with a clean, totally separate track for each. You might, for instance, use a telephone attachment to record a soldier speaking by phone from the Middle East in one channel and in the other his mother speaking into the phone in her front room. Being on separate tracks, you can adjust their levels in the sound mix.
Don’t assume you have two discrete camcorder sound channels until you’ve tested for channel separation. That is, record peak-level sounds on one channel and leave the other in silence. Play back the silent channel at high volume to be sure there is no recorded bleed-through. Reverse the procedure to test the other channel.
Whenever you shoot sound, monitor what you are recording through quality, ear-enclosing headphones (Figure 11-8). Not monitoring, or monitoring with a more stylish substitute like iPod® earbuds, will land you in trouble.
Your best sound, as we’ve said, will come from using a directional mike angled on a fishpole. Position it above, below, or to one side of the frame line. Miking from above is preferable because a voice will then be louder than the speaker’s footsteps and body movements. If this causes fishpole shadow problems, try coming in from the side of the frame. If all else fails, point the mike upward from below frame. This is least desirable because it privileges footsteps and body movements over voice levels.
Suspend your mike in a rubber shock mount to reduce the transmission of handling sounds to the mike. Figure 11-9 shows a common rubber-band model,
which I don’t recommend, next to a more reliable design. Shield the mike from air-current interference, even indoors, with a windscreen (Figure 11-10). This is a rigid zeppelin wind guard, and to it you add a fuzzy fur mini-screen or windsock (Figure 11-11) to defeat outdoor air movement. Absent such shielding, air currents shake the mike’s diaphragm and produce earthquake quantities of wind rumble.
For an inexpensive but practical windsock, wind many layers of cheese cloth around the mike and then pull a black tube sock over it to lower its medical associations.
Getting mikes close to participants without causing shadows takes coordination among recordist, camera operator, and director. Handheld sequences are the most challenging because the mike must not edge into the frame. Miking from a safe distance isn’t an option because S:R ratios decline precipitously and you may wind up with extreme noise and intelligibility problems.
Experienced, on-the-ball recordists constantly scan the subject, the likely edge of frame, and the camera operator for telling facial expressions or hand signals. These might signify, “Watch out, I’m going to swing in your direction,” or “Back off—mike’s edging into frame.” Usually the recordist stands a little ahead and to the left of the camera, in the camera operator’s left-eye sightline (Figure 11-12). The goal is to position the mike as close as possible to, and pointed at, each new speaker while staying just out of frame. Staying close to the sound axes of moving participants, yet keeping the mike from edging into frame, requires the recordist to predict who, between camera and participants, will move next and what direction they may take. With experience, camera and sound people learn to work in perfect balletic harmony—and even to exchange hand or eye signals during the take. It’s a joy to watch.
Sometimes the recordist lifts the mike over the camera to allow the operator to pan left or back away from the subject. If a new sound axis calls for it, the recordist crosses the shooting axis behind the camera and positions the mike temporarily over the camera on the right (Figure 11-13). All the while the recordist tries to maintain eye contact with the camera operator—a choreography all to be managed in silence. Often the sound operator will lightly touch the camera operator’s shoulder to ensure they don’t collide or stumble over objects. Sometimes the director also uses touch to assist.
The ultimate challenge to the mobile documentary unit is a rapidly moving subject who whirls through a street market and then jumps into a taxi, all the while chatting to the camera. Keeping all this nicely framed on the screen and with no sign of the unit’s frantic activity will stretch a crew to its limits, particularly when two extra people silently cram themselves and their equipment around a surprised taxi driver.
Camera and sound subjects are often the same, but when they diverge, the alert recordist covers the sound subject until sound and camera subjects converge again.
In a group scene, the camera may dwell on someone’s telling expression. Someone new starts speaking, so the mike cannot stay with the camera subject but must swing immediately toward the new sound subject (Figure 11-14). Mike placement can be:
In a two-person crew when the camera must track backward, the recordist lightly touches the operator’s back with her free hand to signal, “I’m here and I’m watching for your safety.” This touch includes gentle steering—overzealous would rock the camera—so the operator clears furniture or doorways without looking around. It’s quite marvelous to watch an experienced crew cover all eventualities with balletic precision and confidence. This is something you only get from much practice.
Film recording uses a variety of microphones made by Sennheiser, Schoeps, Audio Technica, and other manufacturers. With microphones, as with so much else, you get what you pay for. You also get better or worse performance depending on your knowledge of the strengths and weaknesses of various types of microphones. Your knowledge is a more powerful influence for good than the cost of the instrument. A friend who teaches sound even says, “There is no such thing as a bad microphone, only bad users.”
Many mikes require battery power, so carry backups and only use the alkaline variety. Other varieties run down and excrete a corrosive mess into the mike body. Some professional mikes require phantom power through a small voltage fed from the recorder via the mike cable. Many nonprofessional camcorders now supply it, but if a mike mysteriously refuses to function, then check the manual to see whether yours is not among them.
Inexpensive microphones, as we have said, don’t necessarily do a poor job—you just have to use them judiciously. Most important is to know sound pickup patterns for each type. The representation in Figure 11-15 of the pickup patterns of three different mikes indicates where, as you circle each type of mike, you’d expect to place a noise-emitting object (think of a cicada in mating mood!) to maintain an equal level recording. The omnidirectional mike is the simplest; it picks up sound equally from all around, so you’d place your cicada at the same distance all around it. To differing degrees the other mike types favor on-axis sound and discriminate that which is off axis. Here are some generalizations:
The hypercardioid or shotgun mike (so-called due to its shape and menacing appearance; Figure 11-16) does the best job of discrimination. A favorite in documentary and electronic newsgathering (ENG) work, it is especially practical in noisy situations. Its drawback is a slight loss of sound warmth and fidelity. More than most mikes, it requires astute handling so it stays out of shot, doesn’t cast shadows, and yet still points at the right speaker in a group. A BBC news crew using a shotgun mike in the jungle was astonished to find it had taken a prisoner during the Vietnam War. Many mikes have small switches that allow you to “roll off” (attenuate, reduce) a particular band of frequencies. A “lo-cut” is useful because it reduces traffic rumble during street dialogue scenes.
Use lavalier or lapel mikes (Figure 11-17) for interviews or speech recording in noisy surroundings. When clipping the mike in place, anchor its cord as the photo shows so as to leave a free loop under the mike. Then, if the cord is touched or yanked, handling noise or damage won’t reach the mike. Participants wear these tiny omnidirectional mikes under upper clothing so they stay exceptionally close to the signal (speech) source. Place them at least a hand’s breadth away from a speaker’s chin or sound levels will vary too much when the speaker’s head swivels. Since you’ll need one lavalier per speaker, multiple speakers require a location mixer (see Part 7: Advanced Production Issues, Chapter 27, Advanced Location Sound).
Body mikes are prone to picking up clothing rustles and body movements—especially when the user wears manmade fibers. These generate static electricity, which sounds thunderous. Ask participants to wear natural fibers, but if they don’t, place adhesive tape between the mike and the offending surface. Lavaliers also excel at amplifying the intestinal activity that follows dining, and they love loose dentures in the elderly.
Lavalier mikes give lovely voice quality but lack all sense of sound perspective— the aural sensation of changing distances that we’re so used to. Staying close to the speaker’s mouth, they pick up little reverberant coloration and thus give no aural perspective changes even when a speaker is visibly on the move. You can emulate perspective changes later in the sound mix if you really need to.
When they work, they’re wonderful. Connect a lavalier mike to a personal radio transmitter, clip a small radio receiver to the camera, and, presto, everyone has complete mobility. Ah, but they have drawbacks. Like mobile telephones, even the most expensive may fade or pull in taxi radios. Be warned, too, that participants forget they are wearing them and may, without your intervention, broadcast their visits to the bathroom. A court used a recording made inadvertently by some of my students at a demonstration as evidence to indict a duplicitous police chief. See Chapter 27, Advanced Location Sound, for wireless mike recommendations.
A wired lavalier, though limiting to your subject’s mobility, is trouble-free compared with its wireless brethren. You hide the cable in the participant’s clothing so it emerges from a pants leg or skirt bottom. Be aware that here, too, people forget they’re wearing them. They walk away until, quite literally, they reach the end of their tether.
Breakdowns often occur in cables and connectors, so carry backup cables. Mikes and mixers need batteries; be sure to carry the right alkaline spares. A basic toolkit of solder, soldering iron, pliers, screwdrivers, adjustable wrench, Allen keys, can of compressed air (for cleaning), flashlight, and an electrical multimeter can get you out of much trouble in the field.
Analyze the sound design of an imaginative film using Project 1-AP-1 Analyze or Plan Using the Split-Page Script Form.
While you shoot, close windows and doors to screen out exterior sound. Switch off any equipment that makes intermittent noise such as air conditioners and refrigerators. Leave your car keys there to ensure you switch them back on after shooting. Any location, interior or exterior, has its characteristic ambient sound:
Ambient sound is only noticeable during silences, but each location and each mike position within that location has its own characteristic presence. One is unlikely to cut well with another.
In a finished film, the audience accepts some ambient atmosphere as part of each new sequence’s reality. The ear identifies the ambient content, then screens it out. Such easy adaptation deteriorates, however, when irritating and intrusive “atmos” changes occur on cuts from angle to angle. To cure this, backgrounds have to be built and adjusted in editing to create a seamless auditory experience. This is how we experience ambience in everyday life, so we expect no less in films.
Before calling for a wrap at any location, whether interior or exterior, let the crew record a presence track (also known as atmosphere, room tone, or buzz track). Do this in every location, every shooting day, because each occasion has its own changing ambience. The procedure is simple:
In postproduction, you can never remove background atmosphere from dialogue tracks. You therefore must add background to quiet tracks so they match louder tracks. This is risky with any dialogue on the margin of intelligibility.
The two minutes of presence recorded on the set, duplicated if necessary to make more, becomes the vital material from which to fill dead spaces in dialogue tracks. These might occur when, for example, you use a cutaway that was shot silent. Because post-production can only add, never remove, background atmosphere in dialogue tracks, the editor must work to make every angle’s background become consistent. Tracks with quiet presence must match those in the angle having the loudest, if all angles are to end up having the same admixture of ambient sound.
Scout locations for camera opportunities, but remember to look for sound problems. If you don’t, participants walking on gorgeous autumn leaves will sound like elephants crunching cornflakes, and the expressway that was so quiet at 2 p.m. will rise to a throaty roar by rush hour.
Every shooting situation comes with problems, which you try to anticipate when scouting the location. Overhead wires turn into Aeolian harps, dogs bark maniacally, garbage trucks mysteriously convene for bottle-crushing competitions, and somebody starts practicing scales on the trumpet. The astute location spotter can anticipate some of these sonic disasters, but not all. In each case, choice of mike, the axis of directional mikes, and getting the mike in close to the desired signal can make a crucial difference. What would life be like without such challenges?
During takes, the crew and any onlookers must be as stationary and silent as possible, and the camera must make no sound that the mike can pick up. Fluorescents like to buzz, filament lamps can hum, and pets come to life at inopportune moments. Mike cables placed in parallel with power cables may produce electrical interference through induction, and sometimes very long mike cables pull in cheery DJs via radiofrequency (RF) interference. Elevator equipment can generate alternating current magnetic fields, and the most mysterious hum sometimes proves to come from something on the floor above or below. Every situation has some degree of remedy, once you have located the cause.
In film sound, you often have to provide what is appropriate and not what was present. To be true in spirit, you reconstruct some sound during postproduction. At the exquisite nature center near where I live in Chicago, there are deer, wildflowers, some prairie, a lake with a heron or two, and lots of wild birds. I have daydreamed about filming a year-long cycle of life there, but it’s under the flight path for the world’s busiest airport, and vehicles roar past only two blocks away. I would need to reconstruct every atmosphere and sync sound because no audience could concentrate on lyrically backlit meadow grasses to the ominous whine of sinking jetliners.
A track shot independent of picture is called a wild track. When a participant flubs a sentence or some extraneous sound cuts across dialogue, the alert sound recordist asks for a wild, voice-only recording immediately after the director calls “Cut!” The participant repeats the obscured words just as he spoke them during the take. Because it’s recorded in the same acoustic situation, the words can be seamlessly edited in.
An effects track (FX) or atmosphere track is a non synchronous recording of sounds that might be useful to augment the sequence’s sound track later. The recordist might carry a small recorder to get tracks of that barking dog, as well as other sounds to help create a composite atmosphere. In a woodland location this might mean getting up early to catch bird calls, river sounds of water gurgling, ducks dabbling, and wind rustling in reeds. A woodpecker echoing evocatively through the trees is probably best found in a wildlife library, since getting near them is hard and background noise is usually high. A sound recordist needs initiative and imagination, and a high level of tolerance to frustration.
In a highly stylized documentary such as Errol Morris’ dreamlike The Thin Blue Line (1988, United States), the imaginative conventions set by the film itself allow great latitude for nonrealistic invention. Under similar circumstances you might conceivably recreate dialogue in a looping or automatic dialogue replacement session (see Chapter 15, Editing: From Fine Cut to Sound Mix), but it is always expensive in time and effort. Sound effects are a different matter; for a sequence in a muddy swamp that had trucks thundering past out of sight, you will have to reconstruct the swamp atmosphere and re-record footsteps in mud. Labor intensive, but creatively effective.
The most potent aspects of sound for film lie not just in faithful recording techniques but in psychoacoustics, a term describing how we perceive and interpret sounds. In this regard, the expert is Michel Chion, whose Audio-Vision: Sound on Screen (1994, Columbia University Press) explains ideas developed over three decades. Be warned that they are far from simple and require learning a specialized vocabulary.
In 1975, the World Soundscape Project began to research the acoustic ecology of six European villages. Sponsored by the Tampere Polytechnic Institute in Finland, the goal is to document acoustic environments in change over many decades. Go to www.6villages.tpu.fi. The Web site reveals the riches you discover when you set out to explore using your ears, something I started learning as a teenager in England from Brian Neal, a musician and great friend who is blind. Every place has its soundscape, and it takes an attentive ear to analyze what makes it individual and special.
To create with sound is to provoke imagination at the highest levels, much as music does. The most memorable soundscapes usually come from simplifying and heightening rather than from being literally true to everything in the location. In sound as in everything else, less is more.
Even the film industry relegates sound to a low priority, so it’s little wonder that sound is the neglected stepsister in low-budget or film school filmmaking. Really, a movie sound track is an orchestral score, something to be designed from the outset so it furthers the aims of the movie you are making.
As you develop your documentary proposal, make a design for the sound you expect to shoot. What kind of world are you showing? What are its special features? What will you need to record, and how? What kind of impact should the sound track make on the audience?
See Chapter 24, Preparing to Direct, for location scouting advice, including a hand-clap acoustics test you can apply to any interior. For more sound information, go to Chapter 27, Advanced Location Sound. An excellent Web site for all sound information is www.filmsound.org. Sound designer Randy Thom talks about feature films and the fact that even fiction directors (whose control is enviably embracing) often lack sound design consciousness. Find excellent information on a variety of sound techniques at Fred Ginsburg’s Equipment Emporium Web site (www.equipmentemporium.com). This user-friendly company sells a wide range of modestly priced equipment and offers good, down-to-earth advice online for low-cost shooting solutions. Download their articles on current equipment such as mixing panels for production sound, an introduction to time code recording, production audio recording for digital video camcorders, reviews of editing systems, troubleshooting guides, and much else. A site with useful basics on effective placing of mikes and other sound-related information is www.soundinstitute.com/index.cfm. Good handbooks are:
Holman, Tomlinson. Sound for Film and TV, 2nd ed. Boston: Focal Press, 2001.
Rose, Jay. Producing Great Sound for Film and Video. Boston: Focal Press, 2008.
Yewdall, Lewis. Practical Art of Motion Picture Sound. Boston: Focal Press, 2003.