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Hertz
So Good: a beginner's guide to audio production for video
by Carma Livingstone
Ah yes, sound.
Elusive sound. Refine your lighting, exposure and mise-en-scène
as much as you like. Your video will not attain all the incredible
heights of impact and engagement without an excellent soundtrack.
Work with me here for a moment. Close your eyes for ten seconds.
C'mon. That wasn't ten seconds. Close 'em again. What did you hear
that you didn't hear before? What did your ear focus on? What did
it let recede to the background? Now know that microphones are completely
incapable of making those distinctions! They are equal opportunity
sound collectors. The hum of a refrigerator. The buzz of fluorescent
lights. The rumble of a bus outside. All of these waves will register
along with your intended target. Welcome to yet another painful
and heartbreaking aspect of video production: good sound.
Hey now. Don't
let it get you down. By this time you are used to painful and heartbreaking
obstacles in the making of videos. Overcoming these challenges is
what makes the whole thing worthwhile. N'est-ce pas? And there are
few simple things you can do to capture sound cheaply, efficiently
and eloquently.
Sound
on the Scene
Here's the simple
truth: the closer your microphone is to the sound source you want
to capture, the better that recording will be. I know what you're
saying: "Well, duh." But this simple truth is quickly
sacrificed when you are out there doing your creative thing. I know.
I know. It's tricky in videomaking for a couple of reasons. If you
are using your camera's onboard mic, the desired location of the
camera does not always match proximity to the sound source. If you
are using an extra mic with your camera, you may not want it to
appear in the shot. Here are some solutions:
1. Check the
area for ambient noise. Close your eyes and determine what extra
sound present. If the air conditioning is on, turn it off. Get as
clean a sound environment as possible.
2. ALWAYS WEAR
HEADPHONES! You would be surprised at the things that can get in
the way of a good sound recording. Mic noise. Hums you didn't hear
before. Letter "p" popping in human speech. Headphones
will allow you to monitor the sound exactly as it is recorded to
tape.
2. The more
mics you have to choose from, the better. Microphones come in two
basic types: omni-directional and uni-directional. Omni-directional
mics capture sound from all points around them. Uni-directional
mics will capture sound from a specific point and isolate sounds
outside their focus. The onboard mic on your camera is likely an
omni-directional. Great for capturing ambient sound in a scene.
If you can get hold of a uni-directional mic as well, then you are
in fine shape. The most all-purpose ones are called "shotgun"
mics. They are long cylinders and will capture sound in a direct
focus, even from far away. Think of them as binoculars for the ears.
Great for capturing human speech.
3. Try to have
an extra person along so you can wire your mic to a long cord. Use
your sound person to get the mic away from the camera and closer
to your sound source. Don't be afraid to create makeshift booms
by taping a mic to a broom handle or a hockey stick. Watch the coordination
of movement between you and the sound person...
4. If you are
capturing human speech in an interview setting, hold the mic about
two inches below the chin and two inches away from the chest. Point
the mic slightly to the right or left of the mouth to get rid of
"p" popping. It's best for you or your soundperson to
hold the mic rather than letting the interview subject hold it themselves.
This is to monitor and correct mic noise and other interference.
Adding
Sound in Post-Production
Here's another
nifty trick. Video editing programs let you add .wav's, .aiff's,
or other compatible audio files into the mix. You can add music,
sound effects, or speech that has been recorded by other sources.
One easy thing to do is to buy a cheap mic for your computer and
record directly into your machine. Some things to watch out for:
1. Make sure
your audio files are all of the same quality and settings. You can
set your audio settings for sound on tape when you import your video.
Note these settings down. When you save audio from sound editing
programs, make sure it has the same settings before you bring it
into your video editing software. At this point, you should work
with the highest quality possible. I work with .wav files at 44,100
kilohertz, 16 bit, stereo. If they are not all the same, you will
experience gut-wrenching and mysterious problems when you export
your movies.
2. When you
are layering sounds, pay careful attention to the resultant audio
levels. Somewhere in your video editing software, there should be
a sound level indicator. You never want your audio to distort (except
for artistic reasons!), as this will produce crappy audio that is
difficult to understand. Also, take some time to finesse the fades
in and out of audio tracks and the transitions in between. This
is where attention to detail in the audio world is most rewarding.
3. Eloquence
over abundance. This tip is simply a matter of opinion. Too many
sounds effects and other novel noises will suck. Simple as that.
When you are tempted to add that comic slide whistle, conjure up
images of desktop publishing in the eighties. We all know the effects
of too much clip art and too many fonts.
Compression
Settings
Here's where
all that hard work is going to break your heart. Compressed audio
can often spawn a horrid and evil twin of the beautiful waveform
you have so lovingly crafted. As with video compression, you want
to push for the highest quality under reasonable file size requirements.
Your options depend on the video editing software you are using.
A rule of thumb: bare audio files like voice only maintain tolerable
quality under high compression. Complex audio files with a lot of
sound and b.g. music need lower compression in order to maintain
the subtleties in sound. The best thing to do is to experiment with
several different settings and see what you can get away with. Don't
be afraid to make the audio into a mono file. You really only need
to maintain a stereo setting if you have edited your soundtrack
to move between the left and right soundtracks. Apart from that,
try to keep the settings as close to those of the original files
as you possibly can.
Enter
into the Audiophonic Abyss
These tips really
and truly are only the beginning. There is much more to know and
learn. All of this I have gleaned through repetition, error, screaming
and near electronic bloodshed. However, in the end, I was utterly
and permanently seduced by the medium of the ears. SOUND ROCKS!
In a magazine
article, Carma Livingstone was once erroneously referred to as a
DJ. In fact, she hasn’t spun any vinyl since 1978 when she
played “Bad, Bad Leroy Brown” 13 times in a row on her
Fisher-Price record player. Visit Carma’s webzine, if you
wish. It’s called “The
Repository for Strange Dreams”.
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