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.
