Editing is the art of manipulating your video images so that you can present them in any order you wish.
But editing alone will not correct an image that is too red or too dark. To correct such problems, you
employ special techniques. Proper white balancing and good lighting will help while shooting, and you can
use signal processing amplifiers in the studio for further corrections.
Many beginning videomakers do not realize that there are techniques and equipment available to correct
and improve your audio as well. You can learn to use special techniques with equipment that will give your
audio a sound that complements the images on your video. In this article, we’ll follow One-take Bob as he
shoots and edits his latest horror classic. We’ll observe what he does as he encounters different audio
problems along the way.
On the Set
We’re at the dungeon set One-take Bob has built in his basement. He’s getting ready to shoot a scene with a
Mad Scientist and his assistant as they mix chemicals at a table and discuss the monster they’re about to
One-take Bob has rehearsed his talent, and he knows that the man playing the part of the scientist has a
naturally loud, booming voice. He also knows that the woman playing the assistant has a rather quiet,
almost tinny voice. One-take Bob likes the sound of the man, but wants a more robust sound from the
Bob has thought it over, and he’ll be shooting from several different positions during this scene. He also
knows that if he uses his camcorder’s mike during each setup, the sound will be inconsistent for each shot,
and will probably have a rather distant tone throughout. He elects to use an external mike.
Bob also knows that if he captures their voices with a single mike hidden in the set, or suspended from
above, he will never be able to make corrections to each individual voice. He elects for this shoot to hide
separate lavalier mikes on each actor.
One-take Bob then connects the lavaliers into separate inputs on his portable, four-channel stereo mixer.
If Bob had been shooting from a distance, he would have used two wireless lavalier mikes on different
channels. He’d then connect the outputs of the wireless receivers to separate inputs on his mixer. With the
mixer connected, One-take Bob knows that he will have control over the individual levels of his actor’s
voices. Bob then adjusts the pan pot controls of the inputs he’s using so that the voices separate into the
right and left channels.
Many mixers have both line-level (a pre-amplified signal) and mike-level (much weaker microphone
level) outputs. Bob’s mixer is like this, so he uses a special splitter cable to connect the left and right mike
level outputs of his mixer to the external stereo mike connector on his camcorder. This cable uses a mini
stereo phone plug with each stereo section soldered to a separate line. Each line ends with whatever
connector is required to connect to the mixer outputs. One-take Bob knows that with this connection he’ll
be recording the voice of each actor on separate right and left channels on the videotape.
Later, while editing, Bob will insert a stereographic equalizer between the audio connections of his
source and record VCRs while editing. Graphic equalizers use sliding controls to cut or boost a wide range
of audio frequencies. With the two voices of his actors separated into right and left channels, Bob can cut
or add more bass or treble frequencies, and therefore manipulate the tone of each actor’s voice any way he
Bob could have done this while shooting by placing the equalizer between the mixer and the camcorder.
Unfortunately, most stand-alone equalizers don’t have mike-level outputs, making Bob’s connection to his
camcorder a difficult one. He would have to use attenuators at the equalizer outputs. Attenuators are like
resistors in that they drop the line-level output of the equalizer to mike level. Bob also knows that poorly
designed attenuators can add noise to his signal, so he prefers to add EQ (equalization) while
Bob could also have used a small mixer with a built-in equalizer and done all of his EQ work
while shooting, but he doesn’t have this kind of mixer. He also prefers to experiment in the peace and quiet
of his editing room to find the right sounds, rather than in the busy, rushed environment of a shoot.
Back to the dungeon. What if One-take Bob’s camcorder only has a mono (non-stereo) external mike
input? Most portable mixers have a mono output. Bob can connect this to his mono external mike jack, or
he can use a mono version of the splitter cable to connect stereo outputs to the camcorder. He need only be
sure that the mixer outputs he uses are of mike-level strength. Connecting line-level outputs to a mike-level
input will cause a great deal of distortion.
What if Bob’s camcorder doesn’t have an external mike connector? Well, if One-take Bob didn’t take the
time to consider his audio needs when he purchased his camcorder, he’s stuck. He’ll have to record
whatever audio he can with his camcorder’s mike. With either a mono external mike input or just the
camcorder’s mike, he may be able to make some corrections with the equalizer during editing. But there
will be a limit to how much correction Bob can make, and the effect will change all the actors’ voices.
That’s why it is so important to consider external mike inputs when purchasing a camcorder.
One-take Bob may elect to use a compressor along with his mixer during shooting. Put simply, a
compressor levels out the output signal regardless of the different strengths of incoming signals. The
advantage to Bob would be that he wouldn’t have to constantly watch and adjust the levels on his mixer to
compensate for peaks and drop-offs in the voices of his talent. Also, Bob knows that when used in small
amounts, compression adds warmth and closeness in human voices.
Some mixers come with compression built in. You can set levels for each input and then switch in
compression to maintain those levels. The main disadvantage is that dialog sounds most natural when
peaks and drop-offs are a part of the signal.
Reverb, Echo and Flangers
One-take Bob is through with this scene, so he and the crew tear down the set and put up a church set. This
is where the Mad Scientist looks out a window over the graveyard while waiting for the monster to come.
Bob wants the audio to sound hollow and airy, as if the scientist was standing in a large cathedral. He
shoots his audio normally, but back in editing, he adds a reverb unit to the audio line.
A reverb unit gives the effect of tightly spaced echoes bouncing around an enclosed room. Bob can also
adjust his modern digital reverb unit to sound like an empty, small room. For the scene Bob is editing, he
cranks up the reverb and the result is a spatial effect, as if the audio were recorded in a large, empty
In the next scene, the Mad Scientist goes down into the catacombs. It’s Edgar Allen Poe all the
way, and One-take Bob wants the audio to sound as if it were bouncing back from many distant
passageways. One-take Bob cranks the reverb unit all the way up into the full echo range. The sound is like
a true echo, and with the proper video images, it can be very scary.
Finally, the monster catches up with the Mad Scientist and a chase ensues throughout the tunnels of the
catacombs. One-take Bob wants the monster to talk, but he wants the monster to sound very strange
indeed. To achieve this, Bob will use a flanger while editing the scenes where the monster talks. A flanger
basically splits a signal into two parts, then very slightly and continuously alters the pitch of one part of the
signal. The result is a very unearthly and spacey effect. Bob decides it’s perfect for the monster’s voice.
Portable Recorders and Nat Sound
One-take Bob has also brought along a good, portable tape recorder. His is a DAT (digital audio
recorder) because he knows that it offers the cleanest sound possible in audio recording. Bob will use his
DAT recorder to record ambient or natural sound, often called nat sound. This is the sound of everyday life
at any given location. For example, if you watch a scene of two people talking at a busy street corner,
you’ll expect to hear their dialog. This same scene would seem very odd if you didn’t also hear car horns,
engine noises, other people walking by or even wind noises.
These are nat sounds, and all professionals know their value in making a scene seem real. This is also
true of a room, and professionals call this room tone. Experienced videomakers will set aside a specific
amount of time to record just the sound of a live mike in any location for mixing into the audio during
editing. The talent and crew must be very quiet during this time for the recording to be effective. Bob
knows this, and he has brought his DAT recorder along just for this purpose.
Bob may also use his portable recorder to record specific NAT sounds. This may be the babble of a
stream, or the hum of a motor, or any other nat sound in or near his scene. In this case, he will place the
mike of his recorder right down near the sound while recording it to get a good level. When added to his
audio during editing, such sounds will give considerably more life to the scene.
One-take Bob is happy to have his DAT recorder for such use, but he also knows that any good portable
recorder, like an audio cassette recorder, will serve the same purpose. He could even use his trusty
camcorder to record NAT sounds.
One-take Bob also uses his portable recorder to record his own sound effects. This way, he can get exactly
what he wants without having to hunt through poor sounding pre-recorded effects. Bob takes his recorder
to the gun range to record gunshot effects, or to the carnival to record the sounds of an amusement park.
Bob experiments all the time with stuff he finds around his home. You can do this, too. Experiment.
Crumple cellophane for fire effects, or shake sand in a cardboard box for footsteps. It’s surprising how
much fun this can be, and how much realism it will add when edited into your audio tracks.
Mixing It Up
Without his mixer, One-take Bob would find editing hopeless. The number of inputs on your mixer is
the only limit to the sounds you can add. You can add sound from an audio effects generator, turntable, CD
player, DAT recorder, audio cassette deck, reel-to-reel recorder, other types of audio tape and disk
recorders and of course your source VCR. You can cue many of these machines, such as a CD player, right
down to a single note of music.
Videomaker has run a number of articles on how to use your VCR’s different audio tracks to add music
and effects to your audio while editing. See Videomaker’s “Sound Reasoning” column for May 1995 for
more on this.
Sync It Up
Professionals have DAT recorders, digital multi-track recorders and even some reel-to-reel machines
available that stripe a track of SMPTE time code onto the audio tape. In this way, they can sync the
externally recorded audio to the video during editing. Unless you are a professional, you will probably find
such equipment only accessible if you win the Lotto.
Instead, One-take Bob transfers all his externally recorded audio to video cassettes. He then puts his
record VCR into audio dub and uses his video edit controller to sync up his audio dub. This works quite
well, especially if you’re using some sort of time code with your editor.
Bob also edits on high-level Hi8 decks that offer PCM audio dubbing and RCTC (rewritable consumer
time code). This gives him enough accuracy to add quality sound effects and music wherever he wants
Many consumer edit controllers offer a GPI (general purpose interface) connector. This is a circuit that
you can use to unpause a slightly modified CD player or audio cassette machine. Most electronic repair
shops can do this slight modification of the player’s pause button. This technique will unpause your CD
player at the start of an edit.
The simplest way is to cue your audio source and then pick a visual cue on your record VCR tape. Start
your tape and when you see the visual cue, unpause the audio source. This will take practice, especially if
you want to fade the sound as you dub.
The Tip of the Iceberg
These are just some of the techniques that One-take Bob used to improve the audio for his horror classic. Of course, he doesn’t always use lavalier mikes or all of the other techniques mentioned. Most
of the time, he experiments to find new ways of adding exciting sounds that improve his audio tracks. So
can you. So let’s get out there and make some audio.