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An Open Letter To Directors From the Production

Our Sound for Picture coverage here at Mix has been criticized in the past for not focusing enough on production sound. Admittedly, our emphasis is on

Our Sound for Picture coverage here at Mix has been criticized in the past for not focusing enough on production sound. Admittedly, our emphasis is on post-production, but we put the call out, and John Coffey of Coffey Sound in L.A. came in with the following. Rather than bring up the decade-old argument about the need for cooperation between production and post, he wanted to focus on the set, with an open letter to directors about how they could help to improve the film’s track.

We, the sound crew, are the ones that you depend on to create and protect your original sound tracks during production. This is, after all, the age of digital sound. Theaters have multichannel digital audio playback. Even home audio systems are often better than many theaters. Yet today’s production sound departments face more problems and greater apathy than ever before.

The majority of the film crew is working for on-camera results, but the mixer’s efforts cannot be “seen” on the set. Almost no one hears what the microphone picks up. Too few are even sure just what it is that we do, so only the most obvious bad noises are brought up for discussion.

Included in our job is to monitor the sets for unnecessary, accidental, ignorant and sometimes even malicious actions (or lack of actions) that may compromise your sound track. We are too often frustrated by the state of conditions that now exist on most sets; many times, we are expected to solve all sound problems alone.

Instead, solving these problems should always be a cooperative effort with the assistant directors and other crafts. The majority of events that ruin sound tracks are totally predictable and happen over and over, show after show, year after year. Let’s try to identify the audio problems that each craft or process brings to your film.


Good sound begins by anticipating the outcome well in advance. Communicate early and often with your mixer in pre-production. Pay the mixer to go listen to potential problem sets ahead of time. Let the mixer make a mock recording to see what noises can be removed in post, just as the DP does with camera tests. Do this before the locations are locked in and before the scouts with your key department heads. If the mixer is still on another show, then have the mixer designate a trusted associate. In the end, it’s cost-effective.


More can be done here to save a film’s audio than in any other department! Set selection should consider sound, but at the very least, try to weigh-in environmental noise factors. Often, we shoot in a place that could have easily had a substitute location. So, when you can’t change locations…

Lock down all the noise problems before we get to the set and always consider the control of the air conditioning. This is a must! Without A/C control, the audio background will change from shot to shot as the air goes on and off. If it is a large building, then have someone standing by with a walkie-talkie to turn the air back on after each shot.

Have control of all noise-makers in locations like bars, offices and hospitals. All refrigerators, computers, ice makers, X-ray and other machines must be able to be turned off. Computer hard drives and fans are particularly important to kill. Request fake prop computers when you anticipate a problem.

Try to schedule filming during nonwork times in locations such as bars and restaurants. Avoid tin roofs during the rainy season. Make sure the electric department can cable the set and still keep the windows, doors and openings closed. And please avoid creaky, old wood floors. They are a recipe for sound disasters.


A few tips: Confer with the sound department when adding noisy set furniture, computers and machinery. Try to consider overhead mics before building low-covered ceilings, hanging lamps and cross beams. Inject foam into constructed stairs and steps to get rid of hollow footsteps over dialog. And, whenever possible, carpet the sets to deaden echo and live rooms. Especially consider taking this step in rooms where the majority of dialog takes place.


First and foremost, budget in a third sound person and the proper amount of audio equipment. A third person provides invaluable support so that the other two can keep rehearsing or shooting. Time saved on set at the moment when every department is ready to shoot are dollars well-spent. When blocking changes necessitate adding a second moving microphone operator, it can be done in a jiffy without stopping production to show someone else how to perform this skilled job. Lots of other problems can be solved more quickly, from killing an errant fan to fixing a director’s headset on-the-fly. In a pinch, the third person can keep production shooting in the event of a sudden emergency or sickness befalling a sound person.


Camera assistants: When (not if) there is camera noise, make all reasonable efforts to contain it by using barneys, glass, blankets, tweaking, etc. Also, don’t turn the slate on and off, as timecode will then be wrong. Let the mixer know as soon as a slate shows any problems. Finally, let the sound mixer know what frequencies are being transmitted in case one steps on wireless mics or Comteks. Be prepared to kill the Panatape when it causes microphone interference.

Operators: Hold only the frame size to be used and no more. Communicate and work out any problems with the boom operator before the first team is called in. Be willing to operate in a pinch with a cover or blanket over a particularly noisy camera.

Directors of photography: There is almost never a good reason to light a boom operator off of the set. An overhead mic in capable hands should be able to dodge your lights; but it is important to give the boom operator the space above the frame, because the sound is never as good with wireless as it is with an open boom mic. Also, don’t use Xenon lights unless the director is informed ahead of time that the whole scene will have to be looped. Finally, when shooting practical car scenes, try to light so that windows can be closed where possible.


Make a reasonable effort to keep the offstage noise-making devices away from the set, and baffle them whenever there is dialog in the same scene. When making rain, put the rain machines and water truck as far away as possible. Use hog’s hair to muffle raindrops on roofs and under windows. When a fan is used to blow a curtain or plant, work it out with the sound mixer before the noise problem crops up after the first take. When using fireplaces, try to limit the hissing gas sound. Heaters on cold sets need to be shut off well before rolling to eliminate the crackle and pops from shutdown.


Cotton is our friend. Silk is our enemy. When requested, the wardrobe department can help by creatively placing the wireless in the best possible position on the actor’s body. Avoid noisy fabrics, especially when the principal actors will wear the same clothing throughout much of the film. And consider the impact on sound when choosing chains, necklaces and other types of jewelry.


Make an effort to keep noisy props as quiet as possible, especially in the following common problem areas: With guns, always let the mixer know if you are using full, half or quarter loads, how many shots are planned to be fired and when they will take place. With table scenes, try to put a pad or felt underneath the tablecloth to muffle dish-clattering noise. Use fake ice cubes in drink glasses. In kitchen scenes, put a cloth down where possible dish noise will occur. Spray shopping bags with a water mister to get rid of paper noise.


Please, use cutters to kill boom shadows. Use all reasonable measures to reduce dolly squeaks. Put a dance floor down if floors creak. Put talcum powder around the rubber wheels when needed. Use blankets to deaden outside sound from open doors and windows. Make baffle covers for the loud set machines, fans and ballasts. Fasten down all scrims and gels that rattle in the wind. On insert cars, keep extra stands attached to speed rails from clanging. Silicon-spray noisy, moving hinges.


Keep the generator as far away as is reasonably possible. Always use a minimum of three banded lengths (150 feet) to the first box, and go back from there. Supply base camp power where possible to avoid loud generators. Use all reasonable measures to keep lights and ballasts from making any noise on the set, and use extension cabling to keep noise-makers off the set. Run cables so that windows and doors can close. Put variacs on problem dimmers. On insert cars, clip and wedge funnels to reduce the rattling sound. Keep lights in silent (nonflicker-free) when shooting at 24 fps to get rid of the unnecessary high-pitched whine.


Set up far away from sets so that the coffee makers and other devices can’t be heard, especially onstage.


When possible, plan to push or pull the particularly loud vehicle out of the scene with human power during the close-ups. Park the trucks as far away from the set as reasonably possible and keep the individual generators off during the shot. Put base camp at least 1,000 feet from set in quiet locations, such as deserts and mountains, and 500 feet away in city locations. Help keep insert cars quiet. Instead of running car engines, use alternate quiet power for picture vehicles that must run flashing light effects during the coverage. Never allow an open stage process car to be used without informing production that the scene will be looped. Especially ask if the tail pipe has been rerouted to the front of the truck and if the onboard gennie is quiet. Use only one key in the ignition to eliminate clanging keys. Don’t Armor-All the dashboard, and use Simple Green to remove it where mics need to be planted. Keep car interior floor area free of all the noise-makers, such as the chains, removed side mirrors, and nuts and bolts.


To mixers, a good actor is a loud actor. Whenever we get together to discuss our jobs, we talk about how good a voice an actor has. Actors who have done a lot of stage work tend to have learned the art of projecting their voice.

A few pleas: Don’t refuse to wear a wireless mic when it is necessary. Don’t ask a boom operator to get out of your eye line. (Acting has been done with the boom for decades. This is a dangerous precedent we have recently started seeing.) Warn the sound department when you will do a much louder or quieter take than was rehearsed. Please project louder when asked; we only ask when we really need it.


None of these implementation plans will succeed if the ADs don’t support your sound on the film. Derogatory statements like “waiting on sound” and “just loop it” are unproductive and sap our spirit. Some points to watch out for.

  • If you are paying police, then use them. Have them lock down traffic when possible.
  • Get quiet lockups on set. Do not allow any walking or talking. Station your P.A.s at key locations outside and especially under windows. “Lock it up” means that we should not hear any work noise from our crews. No engines, talking, etc. Have your walkie set up with priority override function to announce the roll across all walkie-talkie channels being used by all departments.
  • Enforce silent pantomiming from the background extras.
  • Allocate a reasonable time and place for an actor to get wired.
  • When there are closed rehearsals, make sure the boom operator gets to see at least one rehearsal before the actors leave the set.
  • Honor wild line and walla requests before releasing the actors and extras.
  • Honor room tone requests before breaking the set up and stop all talk and movement.
  • In plane- or traffic-infested locations, roll as soon as the engine noise tails; otherwise, another plane or bus comes in and the window of opportunity is lost.
  • Be sure to inform the sound department at least two days ahead of scheduled playback days so the proper equipment can be ordered. Have the office send a post-approved tape with sync. Don’t expect that a CD or cassette will suffice.
  • Have all walkie-talkies, cell phones and pagers turned off during takes and final rehearsals. They can wreak havoc on wireless microphones.


Collaborate frequently with your sound mixer as you would an editor, composer, DP or writer. The difference between good sound and bad sound on many shows is only about five minutes a day of some added tweaking here, another mic planted, a wireless changed there, quieting footsteps, siliconing a door squeak, capturing room tone, a well-placed blanket, killing a machine that came on during a take, powder on a dolly wheel, etc. Usually, by the time you print a take, the problems have been solved. If not, then do another take to be safe.

Here are a few problem areas to watch out for:

Overlaps. When possible, it’s always better not to have overlaps during singles unless absolutely necessary, because you can only be in one cut or the other, and it will cause terrible editing problems. You may decide later that you want to see both sides of the actor’s dialog, but it’s easy to create an off-camera overlap later. Of course, there are times that overlaps must happen for other reasons, and both sides must then be miked.

Using two cameras. It is perfectly acceptable to use two cameras of the same approximate frame size at the same time. The mixer’s nightmare is running one camera wide and another tight at the same time. This means that sound will be compromised by losing “perspective.” All actors must then be wired, because the wide camera will not allow a mic to get close enough to the tight camera size. That means that a sweet-sounding overhead mic may be replaced by an inferior-sounding lavalier. This can be resolved by the second camera only filming nonspeaking actors or not working at all during the wide master shot. Then, go to two cameras for all your coverage.

Rehearsals. It’s fine to have closed rehearsals for actors only, but give one to the crew or at least let the boom operator see one. Otherwise, we can only guess where and how the sound will be delivered. The words we dread the most are “let’s shoot the rehearsal.” You might get lucky, but your sound will suffer and you will do extra takes as unknown problems surface.

Ad-Libbing. Again, it’s impossible to mike lines no one knows will happen. If you want to keep an ad-lib, then do another take for sound if they didn’t get the line the first time.

Air Traffic. Probably the single-most frustrating audio problem on set is being in a plane traffic pattern. You, the actors, and the whole crew knows the sound is no good. Yet, after a while, you have no choice but to plow through and start printing those takes. In that case, rather than looping, it’s much better to get through the scene with lots of short clean pieces that can be cut together later.

Louder Actors. Sometimes we really need you to get the actors to project in order to save a scene. In loud scenes (such as a crowded bar or stock exchange), it’s best to make the actors speak unnaturally loud. If not, then your post background sound will be thin and your editors won’t be able to add the rich background effects to create reality.

MOS and Q-Tracks. Always roll on all takes. It is best to record sound all of the time, because it will make looping much easier when you have a sync reference track to work with. Do not talk over effects shots with no dialog (such as car drive-bys), because post will have to then add more Foley.


The words, “We’ll fix it in post,” should be replaced by, “Let’s fix it on the set.” Reasonable efforts should always be made to do all of these things in a reasonable amount of time. It bothers us to sit quietly in a corner while your sound tracks are being butchered. We care about our work.

Most importantly, find the time to communicate with your sound mixer. You need to know that you are getting the best sound tracks possible. Sound and camera should complement your film in proper proportion. The audience is watching and listening.

Sincerely, Your Sound Department.

Written by John Coffey, with help from Klay Anderson, Brydon Baker, Mike Barnitt, Darren Brisker, Joseph Cancilla, Carl Cardin, Peter Devlin, Carl England, Mike Filosa, Stu Fox, John Garrett, Alexandre Gravel, Robert Gravenor, Mike Hall, Hans Hansen, Larry Long, David Marks, Mike Michaels, Matt Nicolay, Todd Russell, Tim Salmon, Dave Schaaf, Wolf Seeberg, Brian Shennan, Chris Silverman, Scott Smith, Mark Steinbeck, Randy Thom, Noah Timan, Eric Toline, Charles Tomaras, Glen Trew, Von Varga, Mike Westgate, Charles Wilborn, Rob Young, and many others.