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Dialog Recording

If you haven’t read the Location Sound: Basics and Beyond article by Dan Brockett, read it now.

The most obvious part of a movie’s soundtrack is dialog. My definition of dialog is the words and sounds expressed by featured characters in the picture. When recording dialog, it should be as clean as possible. By clean, I mean record the dialog and nothing else. Things unwanted on a dialog recording is the television on in the other room, the refrigerator or central heating/air conditioner that starts and stops in the middle of a take, birds chirping, a radio, traffic outside, and so much more. Record the people talking and only the people talking. In some cases, you might even have to fake some noises on set so as to not interfere with recording clean dialog. For example, if there’s a scene that involves a telephone ring, doorbell, or car starting over dialog, have the actors pretend that sound happens even though you never play it. Then in post-production, mix the dialog with the sound effects, foley work and music score. Seems like a lot of extra work, right? It is, but it gives maximum control in the editing room to make the sound louder, softer, or for example, change the style of the ringer on a telephone. Anything to have more options when assembling the film in post-production is worth the extra time it takes, in my opinion. Speaking of extra time, many people ignore audio problems on set, hoping to fix them by looping (AKA automatic dialog replacement) in post-production This does work and it has been done many times before, but it is not ideal and does not save time in the long run. Actors (especially the amateur ones you begged to be in your movie for free) are never able to repeat lines of dialog exactly how they were said on set. Actors rarely are able to reproduce the same amount of emotional intensity as they had while shooting. So how do you record clean dialog? Good audio starts with decent audio equipment and ends with skill. If you need equipment, check out my Buying Recommendations. The skill will have to be learned over time.

But wait, there’s a microphone on your camcorder. Can’t you just use that? No, never even consider that unless shooting footage for Girls Gone Wild (even they don’t use the on camcorder mic). That mic is designed to capture everything at once. You only want to capture the dialog. Another problem with the built-in mic is that it is, well, connected to the camcorder. In some camcorders, the onboard mic picks up the tape drive motor (talk about a design flaw!). Further, mics pick up sound better the closer they are to the sound source (the actor). This is a problem for onboard mics when shooting a long shot. No on-camcorder mic! Yes, external mic! But which external mic?

Different types of mics are needed for different situations. If you’re a micro- budgeting, do-it-yourself filmmaker, consider yourself lucky to have more than one or two mics–-typically a boom mic and possibly a lavalier (AKA plant) mic. I like to use both the boom and lav mic at the same time. Yes, it is redundant, but not really. Different mics have different characteristics when they capture sound. By recording the actor with two different mics, not only are you covering yourself in case one mic suddenly stops working, but you are also able later mix the two sources to change the characteristics of the dialog (reverb, tone, etc.). When using two mics, be sure to send the two mics to different stereo channels on your camcorder using the mixer or XLR adapter. This way they can be adjusted independently at a later time. On the other hand, it may be impractical to use two mics. For example, in a scene where there’s a lot of movement, the lav may be too difficult to attach to the actor without having excessive clothing rustle. In this case, use the boom mic, but send it to both channels of your camcorder. When sending one mic to two channels, set the gain on one channel 4 dB lower so should the signal get over-modulated and distorted on the main channel, you have a signal 4 dB lower that isn’t distorted. Pretty neat, huh!

Camcorders all have a circuit in the audio processor called the automatic gain control (AGC). This is a filmmaker’s worst enemy. It adjusts the volume to an even level. When there’s a lull in the dialog, the AGC turns up the volume trying to make the various background noises the same volume as the dialog. Some camcorders get confused when one stereo channel is quiet and one is loud and will compensate for the quiet channel regardless of how distorted the louder channel gets (most camcorders share one AGC circuit for both stereo channels). Also, the space on the tape where audio is recorded is very small and tape dropouts can happen. This is why it's important to always have signal on both channels. The new trend in high-end consumer camcorders is to have an option to disable the AGC and let the user adjust the volume (AKA gain). The GL-2, XL-1S, PD-150/170, DVX100 and a few others allow manually control of the gain. Take advantage of this. Always set the gain to about 60%, and then fine-tune the levels at your mixer or converter. Only as a last resort should the camera gain be turned up as it can add noise. While adjusting the camcorder, change the audio settings in the camcorders menu. Each camera’s settings are slightly different, but they all have the only correct setting you’ll ever need: 16 bit, 48khz, 2-channel stereo in SP mode. Not 32khz. Not 12 bit. Not 4-channel recording. Not LP. Use 16 bit, 48khz, 2-channel stereo in SP. Any other setting is sacrificing quality.

The microphone is connected to the camcorder, it is all wired up correctly, sending signal to both stereo channels, and all settings are adjusted. Before the levels can be set, the mics need to be placed. Rule #1 is the closer the mic is to the subject, the better. The boom mic should always be just out of frame and the lav should be as close to the actors’ mouths as possible without being seen. This helps the dialog to be dominant to unwanted noise and also keeps reverberation at an acceptable level. Reverberation is good because it occurs naturally, but it shouldn’t be as loud as the main dialog. Reverb is very easy to add in post, but next to impossible to remove in a recording. Keep it minimal in the recording. Use sound blankets to minimize unwanted reverberation. Sound blankets are the same as moving blankets, are the same as furniture pads–they’re about 15 bucks at a hardware store. Tape them to walls and ceilings not seen by the camera. Now to mic placement.

It is fairly simple for lavaliers. Keep it close to the subject. You can hide lavs under a shirt, in someone’s hair, or on the side of the face not showing on camera. When attaching under a shirt, get it close to the mouth as possible(I once saw someone lav a bellybutton). Use lots of tape. Hairpiece tape works great on skin. Tape the lav solidly in place and then tape the cord, leaving a little slack so there won’t be any tugging on the microphone element. Sometimes taping the lav to the clothing works better than taping to the skin. If it’s a button-down shirt, hide the lav below a button in between the shirt fabric. Or, mount the lav off the actor on anything that’s close to them. I’ve taped lavs to ceilings, letting the cord dangle 6 inches off the ceiling to get it closer to actors. I’ve hidden a lav in between tiles on a bathroom sink. I’ve hidden lavs under ashtrays, in an empty beer bottle, and on a steering wheel, just to name a few. Using a lav as a plant mic is preferable to mounting it to a person because you don’t have to deal with clothing rustle. Get creative about where to put the lavalier. The best solutions are often the strangest. Experiment.

Boom mics and booming is slightly more involved than placing a lavalier. Have you ever noticed in the behind the scenes footage, the boom operator is holding their mic over the actor’s head pointing down? There’s a reason for this. Think of a boom (or shotgun) mic as a gun. It’s going to pick up anything in the direction it’s pointed. If the boom operator is sitting in a chair pointing the mic horizontally at the actor, it will pick up the actor’s dialog and the traffic behind the actor and then anything else in that direction. When the mic is above them pointing down, it picks up the actor and the ground. The ground doesn’t make noise normally, so this is good. The main principal in booming is to use the mic’s narrow pickup pattern to your advantage. Decide how to position the mic to best reduce unwanted noise.

When using a boom mic in a situation that has more than one actor talking, the boom operator should reposition the mic to whoever is speaking. This is called “cueing.” Ideally, the boom operator will be able to cue different actors with minimal movement, by a turn of the wrist (rotating the boom pole on axis). Position the operator in a ‘T’ configuration to the actors. The boom operator will hold the boom pole above her head (maybe even standing on a ladder/chair/platform) so the actors are to the left and right in front of her. When one person talks, twist the wrist to cue them. When the other talks, twist the wrist to cue the other actor. By the way, cueing the actor has nothing to do with how people normally think of directors cueing an actor. It’s just repositioning the microphone. Also, be careful of using a boom mic in close quarters. It is so directional, it can pick up strange echoes off ceilings and walls and windows. Sometimes re-angling the mic will work, sometimes using a sound blanket will work, but there will be times when using the boom is not practical from above. Just go from bellow or from the side, or use another mic if you have one. Rule #1 is to keep the mic as close the actors as possible, just out of frame. Rule #2 is the boom operator should always be monitoring the sound with headphones. Rule #3 is the boom operator should speak up if the sound isn’t good or anything isn’t working properly. It may be frantic on the set, but by fixing the problem and re-shooting any take that didn’t have the sound right, you’ll save loads of time in post-production Booming is a craft. There are no solid rules (yeah, I know). It takes practice, common sense, attention to detail, and a whole lot of upper body strength. Be smart, take time to think shots and blocking out, and speak up if it doesn’t sound good.

Finally. The mics are wired, the camera and equipment is configured correctly, and you’ve figured the best positioning of the microphones. The last thing to do before shooting is to set the levels. Ideally, there will be a person on set whose sole job is to keep the recorded audio at a decent level. But that is rarely the case on micro budget productions. It’s either a “set it and forget it” thing or the boom operator’s job to move the mic farther away or closer to the actors to keep the levels normal. First, set the levels with plenty of room for peaks. Digital audio is great because it has a great signal to noise ratio. However, digital audio also stinks because once the levels peak and over modulate, the signal is permanently ruined. If there’s a signal meter built into the camera or the mixing board, set the levels around 12-16 dBs. Remember that if you ask an actor to do a microphone check, he will always talk louder than when he’s doing the dialog. Instead, ask the actor what he had for breakfast (or to just say his line). After the boom operator has one last break, do a take and listen to make sure things sound good. If there’s a person on set logging, be sure to let them know which takes sounded good and which ones didn’t. Re-shoot anything where the audio stank. It can also help to keep notes to what mics in which configurations were used for each take.

VERY IMPORTANT! Before you leave any location, get room tone. Room tone is the sound a room makes when there isn’t any noticeable sound. Have the crew and actors stop what they are doing for a minute and record a minute of silence. This will save you in post-production when you need to edit the scene. Do this with every mic used for every location.

Now that the dialog is recorded, it's time to start thinking about sound effects.

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