What do the movie The Making of Mr. Right, the television
show Live at the Apollo, and American Express commercials
have in common with your video productions? Sure, the former all
had the advantage of big bucks pro gear and mega-salaried talent.
But they also share the application of audio recording techniques
that you can duplicate with consumer equipment. Like any enthusiast,
we appreciate how simplicity can open up the creative floodgates.
To get the best sound from your camcorder, listen up as I explain
how to use pro techniques with consumer tools.

Proximity Matters

The sound recording tracks produced by modern camcorders are of
pretty decent quality, in general. The number one problem with
their sound is that the microphone, even on the best camera, is
physically too far away from the subject that is being recorded.
(As you may have noticed, it’s mounted on the camera.) Additionally,
the on-camera mike is set up for general use and not optimized
for a particular environment or subject. Thus the main problem
is a proximity problem. All of the other sound in the environment
at hand is picked up by proxy. Moving the camera closer to the
subject will lessen the incidental noises and other sounds in
the environment, but will rapidly limit the flexibility of your
shot.

Take a look at a news crew and you’ll have your most basic solution
to better sound. Notice that even though they have the best field
ENG (electronic news gathering) cameras, there is still either
a sound man holding a separate microphone closer to the subject,
or the reporter himself is holding a mike. Or, in some instances
you’ll notice very small lapel mikes on the subjects. So there
you have the most basic answer to the proximity problem–position
the mike as close to your subject as possible.

Since most of us don’t have access to a professional audio crew
and equipment, let’s focus on the tools you can use now.

Choosing a Mike

Let’s begin with external mikes and learn what we can from professional
performance scenarios such as a news crew or the sound on a television
or movie set. First of all, to begin the comparison you’ll need
an external microphone to record your sound. They’re available
through many audio and video outlets, consumer and professional
alike.

When you look for a microphone, however, you’ll find that there
are many types available, which can lead to some confusion. To
sort through it, first choose the general type you’ll need, then
choose the pickup pattern.

  • Wires or no wires? A good wired mike has the best rejection
    of noise, such as radio frequency (RF) interference, but one usually
    prefers to not see the wires in the shot; so assess this against
    a good 2-channel (true diversity) wireless system. Although a
    single-channel wireless system is more affordable, a true diversity
    system offers the best quality.

  • Stereo or Separate Microphones? Stereo microphones can be very
    good but two separate microphones give much more flexibility than
    a stereo microphone. And they can of course be set up as a stereo
    pair when required. Certainly you want a couple of good mikes
    but that doesn’t mean that they have to be expensive. Look for
    microphones that have balanced connectors (XLR-style) and a good
    frequency response (as close to 20-20,000Hz as you can get).

Pickup Patterns

What follows is a simplified breakdown of the most basic microphone
types and their functions (see Figure 1 for diagrams of pickup
patterns).

  • Omnidirectional–picks up all around, every direction. All
    of the off-point rubbish is picked up, so this type is not typically
    on a list of general-purpose mikes. It’s sometimes used in a Super
    Studio when there may not be a problem with any off-axis sound.
    Its use is limited because point-of-source sound is still the
    main concern; more so in the studio than in uncontrolled environments.

  • Cardioid–picks up sound in an arc in front of the mike. This
    type of mike is the generally the best bet because it has a good
    field of pickup but still allows you to aim it at the source.

  • Super Cardioid–acts like a cardioid but has some additional
    ambient pickup to the rear.

  • Figure Eight–acts like a two-axis cardioid. Useful mostly
    for special applications, so not a good general-use option.

  • Shotgun–picks up directly in front of the mike in a thin straight
    line. A good choice if you have someone aiming it constantly at
    the source or if your subject is stationary. A camera-mounted
    shotgun can sometimes be ideal for an application where the videographer
    is only concerned about picking up sound directly in front of
    his or her field of view.

Microphone Placement

When it comes to mike placement, you’ll gain more by listening
than anything else, but some general direction is useful (see
Figure 2). Put the mike as close to the subject as is practical
and aim it directly at the subject. Keep it from contacting any
vibrating surfaces. Keep the mike away from any serious electrical
or radio-frequency noises. Place it so that wind noise doesn’t
affect it. If your camcorder allows you to adjust the gain (audio
level), run it as hot as practical without overloading (distorting)
the signal.

And now for some special professional cheat hints:

  • Taping a mike to a piece of foam on a broomstick can make a
    pretty good low-budget boom.

  • Hanging mikes from the ceiling above your subject(s), as long
    as the mikes are out of frame, can give a pretty good result in
    some applications. Just make certain they won’t fall and bop somebody
    on the head.

  • Miking from both sides just out of frame by placing two mikes
    on a flat surface perpendicular to your sound source (such as
    a shelf or window frame) can give a good result for miking a room.
    Be sure to lay the mike on a bed of foam or a soft towel to isolate
    it.

Professional cheat hint number two: if you can’t afford an external
mike, consider this method of making a quasi-shotgun out of your
existing camcorder microphone. Completely surround the camera’s
mike with some square pieces of cardboard attached with tape.
When designing your quasi-shotgun, think of it like a set of blinders
for a horse or perhaps a chute into which the audio falls (see
Figure 3). Be careful not to obstruct the vision of the camcorder’s
lens at its widest setting. Also, if the sound you get from this
system is too brittle, you might want to consider affixing some
tissue or cloth to the inside of the construction (called a "wave
guide"). With a little careful construction–and modification
after listening closely–you can have a system that will reject
sound from all directions but straight ahead.

Environmental Considerations

Indoors, the most common problem is unfriendly, spurious
reverberation–that boxy or boingy sound; when you listen back
and say, "That’s not what it sounded like at the time."
Close miking alleviates much of this but if you need more help,
then try to make the room "softer." Commercial moving
blankets (or anything soft of that approximate density) hung out
of camera frame is a very good application if necessary, but a
ruddy pain, so go for mike placement first. Let me add that blankets,
bedsheets, curtains, foam rubber, and many other found items work
very well in a pinch.

The second most common problem is noise in general. Again, smart
mike placement will get you the furthest the quickest, but after
that common sense comes in (close windows, turn off the air conditioner,
wait until the refrigerator stops cycling its compressor). Block
off unwanted sound sources with any of the materials described
previously. For unwanted footstep noise on a hard surface, a rug
or blanket will suffice if you place it out of frame. You can
also re-orient your subjects in the room if the shot allows it,
changing the axis of the mike’s general pickup area to exclude
unwanted noises.

Outdoors, the worst problem is unwanted noise. Mike placement
as always is the primary attack. Here a shotgun mike and its highly
directional pickup pattern may be effective. Aside from that,
re-orientation and axis adjustment, as noted above, is your next
line of defense. Finding creative ways to block off unwanted noise
can help somewhat. The use of a shotgun (not the microphone type)
for birds is not recommended, though you will inevitably consider
this option.

Sub-mixers and External Sound Recorders

To boost the number of mike inputs available while you shoot,
consider a small microphone sub-mixer. For example, you could
get a six-input stereo output mixer and use two mikes for overheads
(in stereo) and then use lapel mikes for the subjects with yet
another mike for, say, the audience. Then, mix them as you like
and send the stereo outputs of the mixer into the camera. Note
to check first (listen!) that you’re recording the balance you
want and make sure you’re not overloading or distorting the sound.

Another piece of equipment often used for audio acquisition
is a stand-alone sound recorder for recording wild sound. Wild
sound is defined as audio recorded separately on location without
any type of synchronization to the video. You can run a sound
recorder of some sort (stereo or multi-track) along with your
camera if you have the ability to edit sound and visuals later.
You could even use a separate camcorder as a way to get its on-camera
mike closer to the action than your main camera’s microphone.

Wild sound has many uses–including the recording of ambient
or environmental noise at a location–but if you plan to synchronize
the wild sound with the picture at some point, you may have difficulties.
One trick here is to imitate the clapboard you see used in motion
pictures. They put the board in front of the lens of the camera
while the camera and sound recorder have already started so that
later in editing the loud clack in the audio can easily be aligned
with the visual of the board physically slapping down. This way,
if you have a system that supports time code or perhaps a nonlinear
editing system, you can align the start of the sound and picture
accurately and very quickly when they are later joined together.

If you do not want to carry around a clapboard, a finger snap
in front of the lens may do. However, one of the major difficulties
you may have with wild sound is called audio drift–the tendency
of the wild sound to subtly and slowly go out of sync with the
moving picture. The clapboard trick does not eliminate drift,
but if you keep your recorded wild audio segments short, you can
minimize its effect.

If you happen to have access to an audio recorder with
time code, so much the better. In professional applications, sound
recordists use time code, a technology developed by the Society
of Motion Picture and Television Engineers (SMPTE) for keeping
track of the audio and visual information on a frame-by-frame
basis for perfect syncrhonization. Some relatively inexpensive
DAT (Digital Audio Tape) recorders can work with time code, but
for the most part, time-code-based audio recording is for those
with access to very expensive recording equipment.

Compressers and Limiters

Just one final note here on audio compressors and limiters: these
devices are used extensively in professional audio-for-video applications.
There is no substitute for hands-on experience with these items.

First of all, compressors and limiters are closely related to
one another. Both work with the dynamic range of an audio source–that
is, its range of amplitude or gain, from the softest to the loudest
levels. Limiting automatically keeps the volume under a pre-determined
level. A compressor, too, acts like an automatic volume control
on what ever you run through it, only it works on both the quiet
and the loud parts of the signal, boosting them or shutting them
down to keep all parts of the signal within a pre-determined range
of amplitude.

What do compression and limiting do for your audio? They give
it a cleaner, more "even" sound that won’t distort or
overload the playback mechanism, even if it’s a tiny little speaker
on a cheap TV. They also bring all of the audio levels into a
workable range so that everything can be heard at nearly equal
volumes.

Going Shopping

When acquiring an audio system, try it out in real scenarios,
and be certain you can return it in a reasonable amount of trial
time if it does not meet your performance criteria.

If you have a limited budget and you’d still like to upgrade
your audio capabilities, focus on an external microphone and a
pair of headphones. Get only what you need, and develop your skill
like the Red Baron.

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