Sound Reasoning: Better Audio from Your Built-in Mike

If you’ve followed the articles in this column for a while, then you know how important good quality
sound is to your videos. And you’ve probably read it here over and over again: attaching an external
mike to your camcorder can help you obtain better audio.

But sometimes, using an external mike is not possible. You might be shooting from a car, or using
a hand-held stabilizing device. Or maybe you simply don’t have a good external mike yet.

So you’re stuck recording inferior audio with your camcorder’s built-in mike. Right? Not
necessarily. There are a few things you can do to help the situation. In this article, we’ll take a look at
some built-in camcorder mikes, and a few simple techniques you can use to improve the quality of the
audio they record.

Hello In There

Most of the built-in microphones common in today’s camcorders use a unidirectional design. This
means that the mike tends to favor sounds coming from directly in front of the camcorder.

These mikes are cheap to make and offer very good audio response, usually from 20 to 20,000
Hertz (beyond the average range of human hearing).

The quality of built-in microphones is not always a factor in getting good audio on your tapes.
Most of the built-in mikes are equal to or even better than many of the cheaper external mikes you can

Then why do we suggest getting an external mike? Because the handling and placement of your
mike is far more important for obtaining good sound than the quality of the mike.

Hearing It

But before we look at handling and placing your camcorder, let’s talk about earphones. If your
camcorder has an earphone (headset) output, use it. There’s absolutely no better way to measure the
quality of the audio you’re recording than to listen to it as you record it.

And I mean listen! Don’t assume that if you can hear your talent talking, everything is okay. Listen
for car horns blaring, a big truck rumbling by, a commercial refrigerator unit chugging away or a plane
passing overhead. These sounds that we take for granted as everyday normal sounds will cause
problems you won’t even realize are there until you play your tapes back. You may listen so hard for
wrong sounds that you ignore ambient sounds like the plane flying overhead. Getting good audio
requires paying attention to what you hear in your earphones.

What if your camcorder doesn’t have an earphone jack? This can be a problem. But since most
camcorders send the audio signal out through an RCA jack while in camera mode, there is a solution.
You could hook a small, battery-operated audio amplifier between the RCA output and your
earphones. I have gotten very good sound using this method in the past.

So the message here is to use your earphones and watch out for unwanted sounds. If you can hear
them in your headset, I guarantee you will hear them when you play back your tapes.

What’s That?

One common source of unwanted sounds is right there under your fingertips. Actually, it
is your fingertips, moving across the body of the camcorder and making all sorts of noise.

Manufacturers use all kinds of nifty little ways to mount internal mikes so as to eliminate noises
made by the camcorder itself (motors, pulleys, etc.). They separate the mike element as far as possible
from the rest of the machinery. They mount the mike element and often all drive motors in rubber
mounts. This certainly helps to cut down on internal noise. But the manufacturers can’t account for the
tapping and rubbing of your hands on the camcorder’s body while you’re shooting.

The problem here is that the person shooting video often doesn’t realize that they’re making sounds
with their hands until it’s too late.

So the first way to improve your audio when using the internal mike is to minimize your hand
movements on the camcorder’s body while shooting. Placing your camcorder on a tripod will help, but
you must still use a light touch when zooming, focusing or using other controls. Better yet, control
these functions with the remote, if you can.

But if you have to hold your camcorder in your hand while shooting, make sure you can reach any
control you’ll need without sliding your hands across the camcorder body. It may well surprise you
how much cleaner your audio will be if you think about what your hands are doing.

Getting Close

Most camcorders provide an AGC (automatic gain control) circuit for their built-in mikes. Basically,
this circuit raises or lowers the recording level based on the strength of the incoming signal from your
mike. They give you the advantage of not having to worry about your audio recording level while
you’re busy shooting.

But the AGC circuit can be a major problem when you want good audio. Weak sound will cause
the circuit to raise the recorded level of everything, including background noise, camcorder noise and
even microphone hiss.

Suppose your talent speaks lightly and you’re shooting from a distance outdoors. You may end up
with so much background noise on the tape that you can barely hear them.

What to do? Get close! With your talent speaking close to the mike, he or she will be the dominant
sound source. The AGC circuit will adjust the talent’s level down for proper recording, and in so doing
will also bring down the level of the background noise.

This method also helps when you wish to pick out specific speakers in a crowded scene. If you’re
shooting a wedding reception or a graduation from several rows back in the seats, you may end up
with more crowd noise than sound from the actual activity. The closer you can get to the action, the
better your sound will be.

You might wish to note that all of the problems associated with the AGC circuit and the internal
mike can also affect any external mike you might move up to at a future date. Practicing these methods
now with your built-in mike will help prepare you for using an external mike later.

Don’t worry about getting too close when you move your camcorder and mike in to your talent (or
sound source). If your lens has a decent wide-angle setting, then there should be no shot setup

Of course, if the background noise in your scene is minimal, you don’t have to get in as close.
And remember: it’s also possible to get too close to your sound source. Say you walk right into the
middle of a rock band while shooting. You may find that the instrument you stand closest to (or its
amplifier) overpowers the others when you play back the tape. Again, listening in with a good set of
headphones will help in these situations.

Stereo Mikes

So far, we’ve talked about ways to get better sound with your basic built-in mike. But built-in stereo
mikes, which differentiate between sounds coming from either side of the camcorder, can cause
problems as well.

Stereo mikes pick up sounds from the right and left sides just as well as sounds from in front of the
camcorder. Because of this, they can be more difficult to use when trying to get quality audio from a
single source. If you’re shooting in quiet environments (indoors, for example), ambient sounds coming
from the side may not be a problem for your stereo mike.

Trying to shoot someone talking on a busy city street can be horror with a stereo mike; all the noise
coming in from the sides comes in at the same level as the talent’s voice. Here again, the closer you
are, the better your intended sound will dominate the recording. In this situation, you might want to
consider making little cardboard sound baffles to place against the sides of your camcorder mike.
These will help block out ambient noise coming from the sides.

A lot of people think that because they have a stereo mike, they can make good musical recordings
regardless of where they place it. But if you’re shooting live music or stage plays, the placement of
your camcorder can make or break your audio. If you’re way back in the audience, your sound may
have a tinny quality, or you may find that audience noise dominates the audio. The sound may also
blend together before it reaches you, causing little difference in the right and left channel playback.
The solution: get closer.

But don’t get too close, because this can cause problems as well. Let’s take our previous example:
you want to tape a rock band’s performance with your stereo mike. You could very well end up with
unbalanced stereo sound unless you know exactly where to stand (near the middle, where you can pick
up all instruments equally).

During a play or stage show, it’s not likely that you’ll be able to walk into the performance. So try
to shoot from the very center of the front rows, if your ticket (or the house management) allows it.

If possible, try to do a rehearsal for every shooting setup and listen to the sound in your
headphones. This is the only way to judge the quality of the sound you’re getting. If it doesn’t sound
right, stop. Figure out what’s wrong or where to re-position and fix it. Use your headphones as a tool to
get good sound.

Consider, Too

Your internal mike can pick up the whirring sound of some zoom and focus motors, especially on
older and cheaper camcorders. This is especially true when shooting in fairly quiet environments.

A good habit to develop is to try to set your shot with your zoom before you start shooting, and to
use the manual focus. This will eliminate any possible noise from the motors that control these
features. If you have to change focus while shooting, do it manually (and delicately).

Another problem is wind noise while shooting outdoors. Even the slightest of winds can create a
booming or thumping sound when it strikes the mike. The only way to control this is with a

Most mikes come with a small foam windscreen. If your windscreen is damaged or missing, you
should replace it. Many accessory catalogs offer small replacement windscreens that are removable
when not needed. A removable windscreen is a good idea. When you’re shooting indoors, or when
there is no wind, you should remove them because they have a tendency to muffle your audio and limit
high-frequency response.

Many new camcorders with internal mikes built into the body offer a switch that engages a built-in
windscreen. Rather than using a foam barrier to block the wind, this system uses an electronic filter
that blocks out frequencies lower then a predetermined range (usually 100 Hertz). This works fairly
well to eliminate the rumble of low-frequency wind noise.

Unfortunately, much of the tonal quality of the human voice (especially the male voice) falls within
these lower frequencies, and the wind screen filter will cut them off as well.

And So

We’ve talked about a number of ways to improve the quality of audio using your camcorder’s
internal microphone. Let’s sum it up:

Use headphones if you can. This is the only way to be sure of what you’re getting. (I won’t shoot
without them.)

Keep your hands still while shooting. Remember that you can make more sound than your subject
simply by rubbing the body of your camcorder.

Get in close. That’s where the best sound is. You’ll get less of what you don’t want if you get more of
what you do want.

In quiet environments, work those features that use motors before you start shooting. Set your shot
with your zoom before you start to record and then focus manually.

When it’s windy outdoors, use your windscreen setting or make sure your windscreen is on before
shooting. Turn it off or remove it indoors.

If you use only one of these suggestions–get closer. This should offer you more audio
improvement than all of the others combined. However, if you try all of these suggestions, you’ll be
well on the road to getting the best possible audio from your built-in mike.

The Videomaker Editors are dedicated to bringing you the information you need to produce and share better video.

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