Understanding and Familiarizing Yourself
with Your Own System
As with almost any technical venture, you
will achieve superior results by
familiarizing yourself thoroughly with your
equipment before you set to work. A great
way to reduce on-location frustrations and
speed up your work flow is to take a moment
to sit down and focus on your wireless
system, crack open the manual, and get some
hands-on experience with all of the
controls. Yes, our lives are fast-paced and
it is not always easy to get a free moment
between tasks (or edits), but time spent
learning the ins and outs of your wireless
system will prove to be well worth the
effort. After dealing first hand with
hundreds of customers wireless systems, we
have found that the majority of setup
problems can be avoided by first reading the
manual. Whether you're on location or taping
an interview, you will most probably be
trying to handle several duties at once, so
to have your wireless setup function
smoothly you should be able to perform the
following without much thought:
1) Adjust your channels (presets/auto scan)
2) Adjust your audio levels (input and
output)
3) Navigate menu (if applicable)
4) Change the battery quickly (this may seem
trivial, but opening some compartments is a
little tricky, or may require a tool or
technique to prevent accidental opening)
5) Lock/unlock transmitter, if possible, to
prevent accidental tampering
6) Confirm the presence of signal on your
system and on the camera (see "Monitoring,"
below). You ultimately want to be able to
instruct someone else easily on its basic
use in case you are lucky enough to have a
dedicated audio person on your shoot.
Maximize your Gain Structure and Physical
Connections
It is imperative that all levels in your
audio chain are properly balanced to prevent
overloads or weak signals from ruining your
once-in-a-lifetime interview. Keep in mind
that although low-recorded signals can be
treated to some extent, strong signals that
cause audible clipping cannot be.
Your wireless
microphone, whether it's a
lavalier,
handheld,
or
shotgun,
is first in the chain and is responsible for
picking up your source before it is
transmitted. Strong sources can over-drive a
sensitive microphone and cause it to
distort, so be sure to keep the element at a
safe distance or choose a more suitable mic
for the situation. Higher grade microphones
have more headroom by design and therefore
can accept higher sound pressure levels when
properly placed. Upgrading your lavalier is
one of the most noticeable improvements you
can make to your system.
When a microphone is
placed in its sweet spot,
the source will seem full, without the
presence of extraneous noise (breathing,
popping, etc). Make sure to run tests on the
subject in question if possible.
The microphone then connects to the
transmitter, which allows you to trim the
input gain (sensitivity) of the signal
coming from the microphone. If this gain
level is set too high it will overload and
distort the internal preamplifier,
especially with an improperly matched
signal. Microphone signals are very low and
require a fairly high level of
preamplification. Some belt-pack and plug-on
transmitters will allow you to adjust their
input levels to accept much higher output
line level signals, like those from a mixer
or recording deck. Make sure that these
controls are properly set, and bring your
input level up to a good working level. On
units with input LED metering or an LCD
monitor you can read your audio input level
(sometimes labeled "AF") without even
switching your receiver on. If no metering
is provided on your transmitter, you will
have to wait until your receiver is on, so
that you can try to detect any distortion by
using your ears (see "Monitoring").
The output of the transmitter is detected by
the receiver, which will also allow you to
monitor the level of your microphone. A
headphone output and LED or LCD metering
system will let you know that a signal is
present, and whether its quality is clean
enough to send to the camera. Once you have
verified the quality of the microphone
sound, you then have the option of setting
the output level of the receiver so that it
will best match your camera's input. Most
video cameras that feature a mini-plug or
1/8-inch input will want to see signals that
are not quite as hot as those you would send
to an XLR-equipped camera, which will
usually offer a bit more headroom. Start
with a low-level output and gradually
increase, as needed, to match your camera. A
common source of signal distortion occurs by
feeding too strong a signal into the camera.
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The next point of connection is the camera
input, and the physical connections will
usually be mini-plug or XLR jacks. Unless
your camera features some form of
undefeatable automatic gain control you will
have on-screen metering, level adjustments,
and at times, line/mic pad switches. This is
one of the trickiest and most important
points in the chain, and is very often
misunderstood. Since you can adjust the
output level of the receiver and the input
level of the camera, you will have to find a
balance between the two.
There are certainly many methods for
achieving a balance, but here is a starting
point if you don't already have one. Check
that your wireless system is set to
microphone level output (most are), and
make sure that your camera is set to
receive microphone level input.
Start by bringing your receiver output level
up to about 1/3 to 1/2, keeping in mind that
some receivers have stronger outputs than
others. You will now be able to bring the
camera level up until you see a signal
sitting about halfway to "zero" on your
meter. This will now give you some headroom
on both sides so that you can compensate for
strong or weak sources. If you have a strong
speaker, and you have already adjusted the
transmitter input correctly (see above), you
may want to back off on the receiver output
a little. On the other hand, turning things
up to compensate for weaker sources can add
system, background, and handling noise, so
add gain judiciously. Optimize your signal
by increasing the camera input level until
the peaks sit comfortably at "zero" on your
meter. All cameras react differently to
audio—some sound best with signals that sit
slightly below the "zero" reading, while
others can take more signal, and sound
better when pushed a little above it.
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If
you will be incorporating a
field mixer
into your setup you will have the
ability to combine several
microphones and sources with more
control. Treat the signal going to
the mixer the same as if it were
going to the camera, and continue
the chain as above. Field mixers not
only offer level control but may
also feature selectable limiting to
help keep occasional loud signals
from clipping. |
Proper Monitoring
How many
times have you found that what seemed to
sound great on location sounds not-so-great
once you get it back to your studio? To get
the most out of your wireless microphone, or
any microphone for that matter, you need to
be able to scrutinize your audio signal in
the field so that you can make the proper
adjustments to optimize it. This is not
always an easy task in the best of
circumstances, let alone a noisy
environment, which means that a pair of
quality
headphones
is a must. Foldable, over-ear, closed-back
models are very portable and will block out
background sounds to enable you to detect
electrical humming or microphone handling
noise more efficiently. When properly fit,
there are even some great noise-reducing
in-ear models available, if you prefer to be
inconspicuous or want to deal with less
bulk. Either way you choose, headphones can
be plugged into both the camera and your
wireless receiver to help track down
overloaded signals, or to help determine
where a failure is occurring. It is
extremely important to know that your
wireless signal chain is clean because the
headphone output of most cameras only
monitors input signal, not what is coming
from your recording medium. Inadequate
headphones may let you know that you have
signal, but they will not help you determine
its quality.
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Don't Be Afraid of Your Controls
If you have a good amount of field
experience with your wireless microphone,
you may have made some of these discoveries
on your own. On more intricate systems,
there is always an untried feature that you
may have overlooked, or a little extra gain
adjustment that you can fine-tune. Don't be
afraid to experiment with your system during
downtime, as it will prove invaluable when
you find yourself under the gun. In the
meantime, stay tuned for more tips on
getting the most from your wireless
microphone such as: "Upgrading Your
Microphone", "Being Prepared for the
Unexpected", "Location Considerations", etc.
Guide to Camera-Mount Wireless Microphone
Systems
How to Capture
and Produce Great Sound for Video
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