State-Of-The-Art DV Sound
Recall, double system sound
involves recording picture and sound separately with a camera and
audio recorder; then syncing them up in post-production. Single system
sound, on the other hand, involves recording picture and sound
together on the same medium. No syncing is required.
Early video cameras left much to be desired in terms of sound, but
many professionals used a single system approach anyway, recording
directly into the camera. The main reasons were ease of operation and
portability of equipment (at that time, video was primarily used for
documentaries and news gathering).
Today, many filmmakers still
believe that video sound is inferior, but this in not the case.
State-of-the-art cameras offer 16 bit digital stereo sound that rivals
CD quality! Even 12 bit cameras provide extraordinary audio.
The Argument Against Double System
Sound
There are several interesting reasons why it's preferable to record
directly into the camera. Taken individually they seem like minor
inconveniences, however, as a whole they make a compelling argument
against using a double system:
-
When recording double
system sound, two media files are created rather than one. This
results in a more complex workflow in post-production.
-
Picture and sound must
be synced prior to editing. This necessitates shuttling, dragging,
pasting, etc., which is time consuming. (No, you can't batch
capture!)
-
Shuttling video and
audio tapes risks damaging them. Protection copies must be made
to protect the masters.
-
If a synced shot is
somehow corrupted, it must be replaced. This entails resyncing and
possibly recapturing picture and sound, depending upon the
situation.
-
When recording original
sound, XLR connectors are used to insure a noise-free signal flow.
This is defeated when sound is transferred to the NLE using the
standard mini-jacks found on computers.
-
Since the material will
eventually windup together again and quality will essentially be
the same, what's the point of recording double
system sound to begin with?
Camera vs. Recorder
In most cases, the best
approach to capturing DV sound is to record it directly into the
camera using a mixer and quality microphones. As usual, mics are
placed as close to the subject as possible using the hierarchy of
microphone techniques (boom, plant, lavaliere, wireless, etc.). Gain
levels are controlled using the mixer rather than the camera, which
gives the soundperson room to work. This is accomplished by
referencing the camera and mixer to each other.
The main drawback of
recording directly into the camera is that the mixer is tied to the
camera by a cable, which limits mobility. This is the strength of
using double system sound-- no umbilical cord. Picture and sound are
referenced to each other with time code, which is used to sync them
later. Depending on the production, mobility may be an important
factor and it may outweigh the post-production problems caused by
double system sound. If this is the case, double system is the
way to go. Obviously, your budget and schedule must be factored in as
well.
Ultimately, the decision to
use double or single system sound is be based on shooting requirements
rather than quality differences. In most cases, you'll find that
single system sound is faster, less expensive and yields great
results.
Micing Techniques
There are four
basic mic placements from which all mic setups are built: boom, plant,
and lavaliere. This priority is sometimes referred to as the Hierarchy
of Microphone Techniques. Let's examine each approach:
Boom
- Booming involves mounting the microphone to a boompole, and
suspending it in front of the subject for optimal sound pickup.
Booming is done by a boom operator. The process is exacting since it
involves juggling many variables at once, such as holding the mic as
close as possible to the subject, moving the mic from one subject to
the next, and keeping the mic out of the picture frame.
The rule of
thumb when booming is to get as close as possible to the subject,
which is just outside the camera frame line. The further the mic is
away from subject, the greater the background noise and echo, so
every inch closer improves sound quality. The mic is normally be
several inches to a foot over the actors head. Up to two feet may be
acceptable depending on the situation.
|
The
rule of thumb when booming is to get as close as possible to
the subject-- right outside the camera frame is ideal. |
Plant
- A plant is any
microphone fixed in place. It is used to cover a static subject when
it is impractical to use a boom. Plants can be conventional
condenser mics or lavalieres. They type of microphone used depends
on the situation.
Placement is
important because plant mics are effective only if dialogue is
directed within their pickup pattern and range. Another important
consideration is that the mic be properly hidden (planted). Mics can
be hidden just about anywhere: behind, on top, and below props,
furniture, and walls. The possibilities are limited only by your
imagination. The newer lavs are so small that they can be used in plain
sight and go unrecognized as a mic.
Lavaliere
- The next approach in the mic hierarchy is the lavaliere.
Lavalieres, called lavs for short, are tiny microphones worn on the
actor's body, either inside or outside the clothing. Most lavalieres
are omnidirectional, which is preferable because they must be
mounted at many odd angles depending on the situation.
Wireless
- Wireless (radio) mics send the audio signal over the airwaves
using a transmitter and receiver. Their main drawback is that they
are subject to RF interference, so a wired mic should be used
whenever possible. They are helpful when the boom operator cannot
get close to the action and it is impractical to run a lav
cable.
