Dynamic microphones used to be the basic workhorses
of the film and video industries, although in more recent
years there has been the changeover to electret condenser
and condenser microphones. Nevertheless, dynamic microphones
remain as important tools to the production sound mixer.
For starters, dynamic microphones can be counted
on to work when other mics won't. Dynamics require neither
batteries nor powering of any sort. They are built extremely
rugged, and are resistant to harsh climatic conditions including
RF and electromagnetic interference.
Dynamic mics offer less sensitivity and reach,
than electrets and condensers. This makes the dynamic mic
unsuitable for most overhead dialogue applications.
On the other hand, this same lack of broad reach
becomes a valuable asset in non-theatrical applications, such
s when recording spokesperson commentary in high ambient noise
environments. Dynamics are recommended for recording location
narration, since they isolate voice extremely well from background
sounds.
Dynamic microphones are also very useful for
recording loud and sudden sound effects, such as crashes and
explosions. Not only are these microphones virtually impervious
to damage from high noise levels, but they also tend to compress
or dampen the audio in such a way s to make these sounds easier
for the recording electronics to handle.
When recording dynamic scenes, in which the
actor is using a handheld microphone as a prop, it is better
in most cases not to take the dialogue feed form that same
mic. Actors may use their hand mics as objects to accentuate
their visual performance, without regard for what their broad
gesturing and handling may to do the sound. Instead, mic your
pretend "stage performers" either from overhead
from a fishpole or boom, or off a concealed lavaliere.
The outward appearance of most handheld mics
can be easily and temporarily change merely by the use of
colored foam windscreens and the addition of color shrink
tubing over the sleeve of the mic.
From SoundWave - The Production Sound Newsletter.
http:\\www.taiaudio.com
http:\\www.pro-sound.com
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The polarity of some condenser microphones that
are made in Europe or for use with older film equipment may
be opposite from that of mics made in North America. Reversed
polarity typically is indicated by a small red dot painted
on a mic's barrel. If you try to use one of these mics switch
video equipment and it seems dead, you may be able to make
it work by placing a phase reverser in the line between the
mic and the powering video equipment.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
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During a recent roundtable meeting, I needed
to mic a stenographer who was recording the proceedings; however,
she didn't want to hear the lavaliere, and I had no table
mics. I folded an index card several times to create a stiff
tab, slid it under the protective glass on the table where
the stenographer was sitting, and attached her mic's tie clip
to it. To Keep the cords from her mic and the others from
being tangled, all were taped to the underside of the table.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
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The problem: An actor in a live performance
has to make several very fast costume changes. There's not
enough time to remove and replace his wireless body-pack microphone
with each change.
The tip: The body pack can be hidden in the
small of the actor's back and held in place by an elastic
bandage wrapped around his body. (Commercial holders with
a pocket for the transmitter and Velcro-type closures are
also available.) The microphone can be run up the back of
his neck and hidden in the hair just above the forehead. Most
lavaliere microphones are deigned with a built-in roll-off
to compensate for the excess low-end frequencies that contact
with the chest produces. Contact with the head produces almost
the same low-end excess, and the microphone works very well.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
Kort Grydenborg of Gilford, Connecticut, read
the tip in the March issue about using a tape dispenser as
an emergency microphone stand and wrote in to say that he
had come up with a different fix for the same problem. He
solved his microphone emergency with a gaffer's grip - a metal
clamp that's normally used to hold a small lighting instrument
The Electrovoice RE-50 microphone is double-insulated
to prevent contact noise from getting into the signal, but
Kort provided further isolation by placing the gaffer's grip
on a mouse pad.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
Some damages to bumpiness are the result of
accidents and some, simply neglect. The only accidental damage
that can be avoided is the abuse caused during shipping. One
way to avoid this is to ship your boompole in an appropriate
container, which can be of the commercially available type
such as the fishing rod holders made my Plano available from
Location Sound Crop,. or you may elect to make your own from
3" or 4" PVC pipe. Either way, your boompole is
protected.
A majority of all boompole repairs stems from
neglect. Most of the poles in use today are made of carbon
fiber and/or fiberglass hybrids which are very tough and should
provide many years of service IF GIVEN JUST MINIMAL CARE.
The single most destructive element to guard against is dirt.
When dirt gets into your pole, it acts like an abrasive and
slowly cuts and wears away at the tubing and locking collars.
In time, those collars will begin to fail, making cueing of
a microphone impossible. If you are working in a dirty or
dusty environment, your pole can be cleaned by simply extending
it to its full length and wiping it down with a slightly damp
rag. Make sure the pole is completely dry before returning
it to its collapsed position for storage. Not e that the use
of any lubricants is NOT recommended since this will attract
more dirt and lessen the effectiveness of the locking collars.
The vdB (van den Bergh) line of boompoles can
be disassembled by hand without the use of any tools. This
allows you to thoroughly clean all of the locking collars
and nylon guides. Also worthy of note is that the nylon collars
used in these poles should be kept as dry as possible. Exposed
to wetness, these collars absorb a small amount of moisture
and expand, causing the pole to seize up. If you pole is accidentally
dunked in water, it should be disassembled and allowed to
dry out.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
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- "The Pole in the Attic"
by Larry Scharf with Felipe Borrero
"The Pole in the Attic"
from:
The Production Sound Report
Spring 1997 Issue
You open the garage, and there they are. Those
gosh darn $$$ poles. Maybe the short one could be used as
a windshield washer extension. They work great if you own
a van or truck. The longer one could be made into a rain gutter
cleaner-reacher or something - or how about a TV remote? Or
you can revitalize them and put them back into service.
Anyone recording motion picture production tracks
knows the importance of a good boom pole. A good pole extends
easily, doesn't bow with the weight of a mic, locks in the
position you set it at, and most importantly, doesn't add
noise to a possible award winning sound track. Good maintenance
is important, especially as the pole ages. Extending and wiping
down each section with a soft cloth is as important as wiping
down the mic cables used with the poles. Grit and dirt wreak
havoc on your pole. It gets inside and erodes the mechanism.
If you have an older LTM or vdB pole that seems to stay loose
and rattle, you know what I mean. In an LTM, the problem is
the plastic bushings wrapped around each section. These are
designed to fill the gap between sections that slide over
each other. These plastic bushings eventually wear down, break
and lose their effectiveness. A simple solution is to remove
the bushings altogether, and replace them with a strip of
female one inch VelcroTM. Yes, VelcroTM! Use one strip per
bushing, making sure the VelcroTM does not overlap itself,
and that it is placed where the bushing once existed. If the
pole is too tight, you can adjust the constriction by shortening
the length of the VelcroTM wrapped around that section. Eventually,
the VelcroTM will wear, but it's a lot easier, faster, and
cheaper to replace than the original bushings.
On a VdB pole, the plastic bushing rings are
permanently mounted. Wrapping the VelcroTM around the circumference,
next to the worn rings, creates a seal, helping to quiet the
pole and clean the pole's sections as they slide in and out.
In some metal poles, the slightest dent can render a pole
difficult to extend. Since the VelcroTM is soft, it conforms
to the shape and slides around the dent if the dent is not
too great.
So, if you have those poles lying around, give
them a second chance; you might just be pleasantly surprised!
If you have any questions or comments, please
address them to Larry Scharf c/o Location Sound Corporation.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
Microphones are precision, delicate instruments
that require periodic maintenance much in the same way as
Nagra recorders or wireless microphones. Various microphones
have unique functional characteristics that require attention.
Failure to maintain your microphones properly can result in
poor frequency response, improper level, distortion, poor
noise readings and a poor pick-up pattern.
For example, Sennheiser condenser microphones
have a tunable oscillator circuit and an extremely critical
RF discriminator adjustment. If either of these adjustments
(made via variable coils) drift, performance of the unit suffers
greatly.
Schoeps capsules contain two filter screens
located between the inlet port and the diaphragm. These screens,
intended to keep contaminates from reaching the membrane,
inhibit optimum performance one they become congested with
debris. Lavalier microphones, though generally less serviceable,
should be checked periodically as well. Their tiny elements
fall prey to the same afflictions as condenser microphones.
Many lavaliere power supplies have active circuitry and need
to have battery and ground contact checks.
All microphone should be checked regularly for
reliable ground connections. Similarly, connector and contact
surfaces should be inspected and cleaned. Routine inspection,
cleaning and calibration are your best assurance to continued,
trouble-free operation of your microphones.
From SoundWave - The Production Sound Newsletter.
Http:\\www.taiaudio.com
http:\\www.pro-sound.com
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A lavaliere is generally defined as being any
small microphone designed to be worn on a performer's body.
In the majority of cases. Lavalieres are omnidirectional in
pattern they pick up sound in all directions). Modern lavalieres
tend to be electret condenser in design, which allows them
to be highly sensitive to a full frequency of sounds, and
also facilitates miniaturization.
Up until recently, lavalieres could best be
described as "proximity" oriented - that is, they
work best when the sound source is close to them. Thus, when
these lavalieres are employed in the normal manner, they tend
to favor the close, or dominate source, and downplay background
ambiance.
This "close -up" sound, emphasizing
the voice and holding back the ambiance, has long been associated
with lavalieres, and is both their strength and their weakness.
Some of the problems that may be encountered
with lavalieres include the difficulties of hiding them under
clothing, clothing noise, wind noise and the loss of audio
perspective in relation to the camera (the dialogue always
sounds "close-up" regardless of framing).
Lavalieres may be used as either "hardwire"
or "wireless". Hardwire means that the actors are
physically connected via audio cable to the mixing panel or
recorder. Wireless refers to plugging the lavaliere into a
small transmitter and broadcasting the signal back to the
receiver, which, in turn, feeds an audio signal into the mixing
panel or recorder.
Regardless of whether the signal is conveyed
by wire or radio, the microphone capsule remains the same!
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
One of the ever-present difficulties in hiding
lavalieres under wardrobe is clothing noise. In actuality,
there are two different causes of "clothing noise":
Contact noise and Acoustic noise.
Contact noise is the result of garments rubbing
against either the mic capsule itself or the leading few inches
of cable (equally sensitive to friction). Contact noise can
usually be controlled - if not completely eliminated - by
careful positioning and taping down of the mic and cable.
Begin by securing the clothing on both sides
of the mic capsule. This can be done by sandwiching the mic
between two sticky triangles of cloth, camera, or gaffers
tape. Form these triangle by folding a few inches of 1"
wide tape corner over corners, similar to folding a flag.
By immobilizing the mic between both layer of
clothing, you have eliminated the possibility of either layer
of clothing rubbing against or flapping onto the microphone.
If the lavaliere must be positioned between
skin and clothing, or attached directly to the skin, then
a professional medical/surgical tape should be used against
the skin.
Once the mic capsule has been secured, the next
step is to for a strain relief for the thin cable. Make a
small loop just under the mic capsule. In the case of very
sensitive mics, such as the Sony ECM-77, the Sennheiser MKE2,
and the SankenCOS-11, make the loop goes around twice. Tie
a small thread or use a thin strip of camera tape (sticky
side out) to preserve the loop. Tie the loop loose enough
so that it can "Breathe" (change diameter to absorb
tugs).
Apply a few inches of tape along the cable below
the loop. Any tension on the cable will be absorbed by the
garment, rather than by the microphone (which is somewhat
isolated by the floating loop).
The remainder of the mic cable can be run under
clothing and can terminate either at the waist or the ankle.
The end of the mic connector should be secured so that it
does not dangle freely.
During a take it becomes a simple matter to
plug in an extension XLR cable. Afterwards , the talent can
easily be disconnected so that he or she is free to roam around.
When using an external "tie clip",
it is still important to think in terms of creating a strain
relief. Loop the thin cable up and under the tie clip, forming
a semi-circle , and passing through the wide hinge of the
clip. Continue the loop behind the garment, and bring the
cable around downward, thus completing the circle. As the
cable loops downward, it should be inserted between the jaws
of the tie clip and the back of the garment Hide the balance
of the cable behind the wardrobe. SEE PHOTO FROM PG 83 FROM
LOCATION SOUND CATALOG.
Not only is this arrangement more pleasing to
the eye than a dangling cable, but the floating loop of the
cable isolated the mic while the grip of the tie clip serves
as a strain relief.
Acoustic clothing noise is the sound generated
by the clothing itself as garments or layers rub against each
other when the actor moves. Noise is much more prevalent from
synthetic fabrics than from natural cottons or wools. There
is no simple remedy, only prevention, so it is wise to consult
early with the wardrobe department.
However, there are a couple of tricks that may
help. Anti-static sprays, such as Static Guard, will reduce
static electric discharge, clinging, and reduce friction.
Dry silicon spray lubricants sometimes help, but be careful
of staining. Stiff or starched clothing can be softened with
water or alcohol (make sure the colors don't bleed). Saddle
soap, silicon, or light oil can take the bite out of hard
leather.
Another noise problem common to lavalieres is
that of wind noise. Manufacturers usually supply small foam
or metal mesh windscreens with their lavalieres, but these
are usually more effective against breath pops than against
outdoor gusts of wind.
Lavalieres used under clothing have the advantage
of being partially shielded from the wind, but may still require
added protection.
Clothing rubbing against windscreens can be
extremely noisy, so great care must be taken when using hidden
lavalieres out of doors. Surrounding the windscreen with sticky
tape and securing it to both layers of clothing, as you would
a bare mic, will reduce the friction noise. However, the tape
may destroy a foam windscreen with it is removed! Inexpensive,
expendable windscreens can be make by wrapping the mic in
acoustafoam; or by pulling the foam booties off of video cleaning
swabs.
Cheesecloth over a mic works very will against
wind. Another Hollywood variation is to snip the fingertips
off children's woolen gloves, and pull the wool tips over
lavaliere wrapped in foam or cheesecloth.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
The phrase "ENG shotgun" has come
about as an informal means of referring to moderately priced
(compared to true condensers) directional microphones. All
of these microphones are commonly described as permanently
polarized, fixed charge, or electret condenser design.
Electrets are definitely a major step up from
dynamic mics and are suitable for ENG, corporate, and other
applications where budget, convenience, ruggedness, and self-contained
mic power may be important.
Unlike regular condensers that require higher
voltages to operate (12 to 48 volts), these electret mics
require only a the microphone body provides the necessary
power. Since the electret condenser microphone is self-powered,
it can be plugged directly into the regular low impedance
"dynamic" mic input of professional mixers and recorders.
We do believe it is important to point out that,
although all of these ENG shotguns offer excellent value for
their moderate price, they do not offer the high sensitivity
and extended reach of the more sophisticated (and more expensive)
condenser models.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
A majority of the production dialogue recorded
in major "Hollywood" theatrical productions and
television series is miked from overhead, utilizing either
a fishpole or studio boom.
Overhead miking provides a natural sound. Normal
sound effects and some background ambiance are also picked
up, and at lower relative level than the dialogue, thus rounding
out the total track.
Perspective matches camera angles, since the
boom mic is able to get in closer on tight shots, and is further
away on longer angles.
In contrast, the use of lavalieres and radio
mics produces dialogue that is often sterile in texture -
lacking natural sound effects and ambiance. Perspective is
always forced and "close-up" - regardless of camera
angle. ?Audio is often subject to abrupt changes in presence,
such as those caused by talent turning their head off-axis
to the lav, or leaning over a hard surface (such as a desk
or podium). Last, though surely no least, lavalieres are prone
to distracting clothing noise and other interference.
A good technique is to follow the same approach
towards dialogue recording as practiced by feature mixers:
Use lavalieres with discretion and take advantage of overhead
miking as much as possible.
Microphone selection plays an important role
in overhead miking technique, along with choosing a skilled
and experienced boom operator. Just like camera lens focal
length, there is no one choice of specific microphone that
will be right for all situations A professional package should
include an assortment.
It cannot be over stressed that, for best results,
only the highest quality condenser microphones - such as those
discussed in this section - should be used in capturing dialogue.
Although most electret condensers are very good microphones
for their price and features, they simply do not perform as
well as condensers for professional or theatrical dialogue
applications. Top of the line condensers offer superior reach
and sensitivity over the electrets, and that can spell out
the difference on those more demanding shots between getting
'rich' dialogue versus 'weak' or 'thin' audio.
Allow the extra room in the budget to purchase
or rent a package of true condenser microphones along with
the proper accessories (power supplies, shockmounts, blimp
windscreens) to make them work.
Similar to telephoto lenses, shotgun microphones
tend to compress the distance between foreground and background.
Avoid pointing the mic as if it were a rifle, unless you are
totally unconcerned about bringing up the background. Be careful
of what is I the "line of sight' behind the talent.
The best way to eliminate this "telephoto"
effect is to aim the mic down from above, so that the only
"background" in the microphone line of sight is
the silent ground.
The most popular microphones for exterior use
are long shotgun microphones. Long shotguns offer narrow pick-up
patterns and excellent sensitivity and reach. Deployed overhead
of talent, tilted just slightly towards the mouth - these
mics will eliminate considerable background ambiance while
still picking up natural sound effects such as footsteps and
hand business. Because of their directionality, these long
shotguns can be played at greater headroom above the actor
when necessary (up to several feet depending on ambient noise),
thus facilitating the wider frames more common on exterior
set-ups.
The disadvantages of the long shotgun are its
directionality and physical dimensions. The narrow pick-up
pattern requires that much more care be taken in cueing (aiming).
Moving talent must be meticulously followed; multiple talent
requires rapid and precise repositioning of the mic for each
person's lines. The physical length sometimes becomes a problem,
for example, in interiors with low ceilings.
The extended length of the shotgun is usually
not a problem when working outdoors, although situations may
arise where a shorter mic is necessary. Weight, on the other
hand, can be a definite problem Do not underestimate the strength
required to manually support a fully extended fishpole complete
with shotgun mic, shockmounts, and windscreen over the course
of a long day!
As mentioned before, there are situations when
a long shotgun may not be the microphone of choice due to
size, weight, or narrow degree of pick-up.
The short shotgun is characterized by its more
manageable length and wider pick-up pattern (supercardioid
or hypercardioid). The somewhat wider (though still very directional)
pattern makes it easier to follow, or cue the talent. On the
other hand, the effective working range (maximum distance)
of the mic is diminished. Also, the wider pick-up pattern
tends not to isolate talent from ambient noise as well as
the long shotgun.
Interior situations pose an entirely different
set of problems for the sound mixer. It becomes a question
of striking a balance between reach versus acoustics.
Shotgun microphones with interference tubes
tend to exhibit loss of definition when used in confined,
hare-walled interiors such as kitchens, bathrooms, small offices,
and so on. This phenomenon is caused by reflected sound waves
interfering with the acoustic noise canceling principles employed
with the interference tube.
The solution is to use the wider-angle condenser
mics without interference tubes. The problem is that these
wider-angle mics (cardioids and hypercardioid) also have less
reach. It becomes a matter of trade off between choosing the
crisp sound offered by the wider pattern mics versus getting
the reach needed to isolate dialogue from the background noise
due to higher distance often demanded by the camera angle.
Very popular condenser microphones offered at
Locations Sound include AKG, Audio-Technica, Beyerdynamic,
Neumann, Schoeps, and Sennheiser.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
Foam windscreens and pop filters are intended
to provide protection against low velocity moving air, such
as would be encountered from performers exhaling onto the
mic. Foam windscreens also protect sensitive condenser mics
against the motion of room air caused by normal ventilation
ducts as well as from the physical act of moving the microphone
while mounted on a boompole.
Although some handheld performance mics come
equipped with built-in wind or pop protection, condenser microphones
should never be used without a protective windscreen!
Do not expect a foam windscreen to function
adequately out of doors even on calm days, there will occur
occasional soft gusts of wind that will penetrate the foam
and cause audio overload. Employ a blimp type windscreen,
such as a Rycote. However, it is beneficial to use a slim
foam windscreen inside of the blimp, providing that at least
½" or more of airspace remains between the foam and the
inner walls.
Foam windscreens also provide a quick means
of altering the color and appearance of microphones. Some
sound mixers place a white band of tape around the front tip
of the windscreen. This facilitates the camera operator identifying
the microphone through even a dim viewfinder, where otherwise
it might go unnoticed until brightly projected during dailies.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
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If you desire an easily recognizable song for
your video, but you don't have a budget for using copyrighted
music, you might want to consider music from the public domain.
For more information about the public domain,
a list of songs in the public domain, and links to other related
sights, go to: http://www.bright.net on the web. The site contains a
wealth of information. If you still have questions after reading
all the information available, you can always leave questions
via e-mail.
Bryan Mecklenburg
Hudsonville, Michigan
From:
Videomaker
May 1997
http://www.videomaker.com/
Top of Page
If your camcorder has a stereo mike input jack,
you can record wedding ceremonies with both a wireless mike
placed on the groom, and a zoom mike mounted on the camcorder.
Using a cable with a 1/8-inch stereo mini plug
on one end and two mono 1/8-inch jacks at the other end, two
sound sources can be recorded simultaneously, each in synch
with the video.
For the final edit, you will have at your disposal
general sound from the zoom mike mounted on camera and close-up
audio of the exchange of vows recorded through the wireless
mike.
If you discover later that the wireless mike
has static or drop-out, or that you were too far away for
your zoom mike to be effective, don't seat it. You have a
back up!
Jeff Goldberg
Manalapan, New Jersey
From:
Videomaker
March 1997
http://www.videomaker.com/
Top of Page
Although the temptation is often great, the
novice production sound mixer should avoid attempting to "improve"
location soundtracks by means of equalization. Adjusting the
highs, mid-range, and bass from shot to shot may sound fine
in the headphones, or even in dailies, but when shots are
intercut during the editing process, changes in voice and
backgrounds often become annoyingly apparent.
Any equalization one chooses to employ during
the course of the productions should remain consistent throughout
the audio tracks. For instance, some mixers like to add a
pinch of mid-range boost to enhance the clarity of the dialogue-
and this same setting is used virtually all of the time, regardless
of actor or location.
It is common for mixers to "roll off"
excess bass, since the extreme low frequencies contain rumble
and wind noise. Low frequencies are often not accurately reflected
by many audio level meters, and low frequency noise can contribute
to overload distortion. On interior sets, use a mild bass
"roll off", around -6dB at 90 Hz. Exteriors often
cal for a more sever low cut, around -6 dB at 150Hz.
Finally, use EQ sparingly. If in doubt, leave
everything in the "normal" positions. Any EQ changes
that are necessary to improve the track are best left for
post-production, where "improvements" can be timed,
rehearsed, previewed, and undone when they don't work!
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
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A few words on the improper use of household
wiring (110 Volt AC power) on the set. Our Service Department
is seeing an alarming increase in the number of mixing panels
that have been subjected to 110 volt AC on their line outputs.
Depending upon how the mixer is wired, exposure to 110 volt
AC can produce damage range from something as minor as a blown
fuse all the way to the total destruction of the mixing panel.
I'll bet I have your attention now!
The scenario I am referring to is sending an
audio feed to a video assist system. In the past, it wasn't
much of a problem because most sound mixers used Nagra based
battery powered systems. With the increased demand for R-DAT
based recording systems and their accompanying increased power
demands, we see more people resorting to AC to power their
equipment. This means that the recording channel is grounded,
and if there is a wiring error in the AC feeding the Video
Assist or in the Video Assist system itself, the potential
for disaster is set.
My recommendation is never ever send a hard
wired feed to anything running on AC power without an isolation
transformer like the Sescom IL-19, or better yet, send the
audio out using a Comtek or any other wireless system, and
the potential for this problem is eliminated.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
In recent years the Federal Communications Commission
(FCC) has seen fit to open up the UHF frequency range for
wireless mic use. Frequencies between 450 and 960 MHz are
now available, and are being used to full advantage by such
major manufacturers as Sennheiser and Cetec-Vega.
The uncrowded nature of this frequency range,
as opposed to the cramped quarters of the VHF band, have made
one-time frequency placement problems a thing of the past.
Television stations on UHF are a much more rare commodity
than those on VHF, so potential interference from our TV colleagues
has been reduced drastically.
Also, the sheer number of available frequencies
reduces potential interference. These, along with the manufacturers
using slot frequencies whenever possible, have made UHF radios
the choice of may professionals in the audio field.
Don't get us wrong, potential problems do exist.
In the Location Sound Corporation Rental Department, we always
find out where our customers are using their wireless. But
with UHF, it takes only a quick glance on a frequency map
as opposed to the sometimes extensive scheduling and coordination
problems faced VHF.
Other advantages of UHF include and FCC approved
150-milliwatt transmitter versus a 50 watt maximum for VHF
(great for stage use).
All of us in the Rental Department are certainly
sold on the new generation of UHF wireless mics. Their performance,
dependability, and well though out features make them a problem-free
rental item. The next time you need wireless, try UHF. Give
us your critique. We're sure you won't be disappointed.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
The transmitter input gain is the single most
important adjustment on any wireless mic system to insure
optimum signal to noise ration. The audio signal to noise
ratio will never be any better than it is at the transmitter
input. If the input signal is noisy at the transmitter, there
is nothing else that can be done later to restore it to its
original quality. The audio level is adjusted with the gain
control on the transmitter, with some sort of level metering
on either the transmitter or receiver.
The most difficult problem with properly adjusting
the transmitter input gain involves duplicating the user's
voice level in advance of the actual performance or use. Obviously,
you need some sort of metering in order to correctly set the
transmitter input gain. The metering must indicate the modulation
level of the radio signal and also limiting in the transmitter.
All Lectrosonics Pro Series transmitters provide LED level
metering for this purpose. Metering is also provided on the
receivers, but often times the transmitter metering is easier
to use, since the receiver may not be accessible or visible
from the transmitter during setup.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
Many of today's more popular wireless microphones
such as he Vega Dynex III and the Sennheiser HIDYN rely on
analog companding to increase their dynamic range.
Companding is a term used to describe the compression
and re-expansion of an audio signal. Both Vega Dynex III and
Sennheiser HIDYN work in a similar fashion: The incoming audio
signal is compressed in the transmitter, used to modulate
the RF carrier, and again transmitted. Upon reaching the receiver,
the audio is detected (separated from the RF signal) and expanded
to its original amplitude. Although it seems quite simple,
the process requires that all compression and expansion rate
be precisely matched.
The use of companding in wireless mics allows
greater dynamic range without the need for increased RF carrier
deviation. This pleases both the sound mixers and the FCC.
It should be noted that the compression portion
of these companding circuits is independent from the externally
adjustable compressor limiter (affecting microphone gain)
found on most wireless equipment. Due to the precision matching
required, Dynex III and HIDYN circuitry are not user adjustable.
However, because the compressor limiters are
externally adjustable on the transmitter, poor dynamic range
and/or distortion can occur as a result of misinformed use.
This user adjustment is made via the mic gain control and
should be set so that the loudest expected portion of audio
just activates the limiter - which is generally indicated
by meter deflection or a lit LED.
Normal audio should remain low enough so as
not to trigger the built-in limiter. Desired increases in
gain can be achieved by raising the input level at the mixing
panel or recorder, rather than by increasing the mic gain
on the transmitter. A few minutes spent properly adjusting
mic gain & limiter with regard to vocal attributes of
the talent will greatly improve recordings.
Microphones are precision, delicate instruments,
which require periodic maintenance much in the same way as
Nagra recorders or wireless microphones. Various microphones
have unique functional characteristics which require attention.
Failure to maintain your microphones properly can result in
poor frequency response, improper levels, distortion, poor
noise readings, and a poor pick-up pattern.
For example, Sennheiser condenser microphones
have a tunable oscillator circuit and an extremely critical
RF discriminator adjustment. If either of these adjustments
(made via variable coils) drift, performance of the unit suffers
greatly.
Schoeps capsules contain two filter screens
located between the inlet port and the diaphragm. These screen,
intended to keep contaminates from reaching the membrane,
inhibit optimum performance once they become congested with
debris.
Lavaliere microphones, though generally less
serviceable, should be checked periodically as well. Their
tiny elements fall prey to the same afflictions as condenser
microphones. Many lavaliere power supplies have active circuitry
and need to have battery and ground contacts checked.
All microphones should be checked regularly
for reliable ground connections. Similarly, connector and
contact surfaces should be inspected and cleaned. Routine
inspection, cleaning, and calibration is your best assurance
to continued, trouble free operation of your microphones.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
Wireless microphones can be categorized as handheld,
body pack, or plug-on; VHF or UHF; and diversity or non-diversity.
Hand helds refer to the hand held microphones
that have transmitters built into them. They are popular for
vocalists, and variety stage performance. Body packs consist
of transmitters only and can be thought of as "wireless
cable" rather than "wireless mics," since any
microphone (with the appropriate adapter cable) may be plugged
into them. Body pack transmitters are generally used with
lavaliere microphones. Wireless units can also be used with
a condenser mic on a fishpole or a stationary mic planted
on the set.
Wireless mics can be VHF or UHF. Most professional
units share the upper VHF television bands (TV channels 7
through 13). If you expect to be shooting out of town or on
the road, make sure there are no local TV stations broadcasting
on the same frequency as your radio mics. For instance, manufacturers'
designated (A) "traveling" channels (169-172MHz)
are popular for use in most places across the United States.
Wireless microphones are available in the UHF
frequency range. The UHF frequencies, compared to VHF, are
less susceptible to most common sources of radio interference.
A greater number of UHF units can be operational at the same
time without cross interference, a definite advantage when
doing stage and variety work. Another advantage of UHF is
that the transmitter antennas on the body packs are very short
and do not require careful rigging to the actor's clothing.
"Diversity" receivers work on the
principal of switching between two receivers, with antennas
placed at least ¼ wavelength apart. The diversity unit compares
the incoming signals continuously, and instantly switches
to the better signal, thus eliminating "drop outs"
or dead spots.
BODY PACK APPLICATION:
Without question, the most difficult aspect
in using radio mics is correctly attaching them to the body
of the actor or actress.
Body pack transmitters can be hidden almost
anywhere. The most common sites include the small of the back,
rear hip, inside thigh, ankle, pants pocket, and inside chest
pocket of a jacket, or in the heroine's purse. When talent
is wearing a scant bathing suit, for example, radio mics can
sometimes be hidden under straw hats, or even on the back
of the neck under long tresses of hair. Leg warmers provide
a convenient place to hide radio mics when dealing with exercise
attire.
There are a number of ways transmitters may
be secured. Belt clips work fine under a jacket or loose top.
Special pouches or pockets can be pinned (or permanently sewn)
into wardrobe. Sometimes it is possible to merely hang the
unit with a safety pin that has been tapes onto the transmitter
casing. Specially constructed elastic belts known as belt
and pouch kits, such as those manufactured by PSC, can be
worn around the waist, thigh, calf, or ankle. Transmitters
can be also held in place by elastic bandages.
Any time camera and gaffer tape is used, special
care must be taken not to tape directly to skin or delicate
wardrobe (such as nylon stockings). Fold the tape over itself
to form a non-adhesive strip to wrap around first. Better
yet, use some sort of liner, such as a strip of cloth. Avoid
placing the transmitter directly against the skin; since body
moisture tends to interfere with (absorb) the outgoing signal.
Care should be taken in securing the flexible
transmitter antenna cable. To prevent the antenna from being
torn from its connector the first time the actor moves or
bends over, use a rubber band to provide elastic strain relief.
Attach one end of the rubber band to the tip of the antenna.
The free end of the rubber band can be safety-pinned to the
clothing or taped in place (use medical tape on skin). Thus,
the antenna can be maintained reasonable straight (a little
bit of slack is okay) yet protected against damage.
The transmitter antenna can be run vertically
up or down from the body pack. However, if the antenna trails
downward, then the transmitter should be mounted in an inverted
position to avoid making a loop in the Antenna. The transmitter
antennas can also be run horizontally, such as partially around
the waist. However, in these instance, the receiver antenna
may need to be tilted sideways (matching the angle) to improve
reception.
Under no circumstances should the mic line and
antenna wire ever cross. This will definitely reduce your
range. Run the mic cable out from the body pack in the opposite
direction of the antenna. When the transmitter is mounted
on the body upside down (the antenna running downward), it
is okay for the mic line to loop upward, as long as it doesn't
cross the antenna. Install a fresh battery in the transmitter
every time you use it. It sounds like a detail that should
be obvious, but all too often, radio mic problems boil down
to a weak battery in the transmitter. Change the battery frequently
- every four to six hours with most brands.
FORCED PERSPECTIVE:
There are a couple of ways to soften the problem
of forced close-up perspective. The first is to select a lavaliere
with an open sound, such as the PSC MiliMic, Tran TR-50 or
Sennheiser MKE-2, rather than a lavaliere that tends to isolate,
such as the Sony ECM-55. Another solution is to attach the
lavaliere a little lower on the body than usual. When there
are two people playing close to each other, it sometimes helps
to mic each person off of the opposite person's microphone.
ANTENNA PLACEMENT:
The antenna of the receiver should initially
be adjusted to match the angle of the transmitter antenna.
Then experiment with changing the angle, for sometimes an
unusual condition on the set may favor an odd combination
of antenna angles to yield best signal.
A clean line-of-sight between receiver antenna
and transmitter is important, since almost any object or body
and deflect or absorb the RF signal. Mounting the receiver
on a wooden ladder usually helps.
Wireless mics come equipped with one of two
forms of receiver antenna: the straight wire "whip",
or the shorter helical "rubber ducky". The straight
"whip" will yield the best reception, although the
"rubber ducky" offers more convenience in terms
of mobility.
There are some special antenna systems that
can be used to improve reception. Directional antenna systems
can be used to reject radio interference, when the source
is identified. High-gain antenna systems can significantly
increase the range of most wireless mics.
Anytime the receiving antenna is separated from
the receiver, care in selecting low loss cable becomes important.
50 ohm RG-58U is a standard cable, however it has significant
loss especially at higher frequencies, keep the cable length
as short as possible, and select lower loss cable for longer
cable runs and higher frequencies.
PLACEMENT AND ENVIRONMENT:
Strive to maintain minimum distance between
the transmitter and receiver. Move the receiver/antenna from
shot to shot in order to achieve close and clean line-of-sight
placement. Don't' be afraid to locate an antenna just outside
of camera frame, or even to conceal it behind a prop right
in the shot or set itself.
Sometimes, it maybe expedient to have the boom
person or third person physically carry the entire receiver
during the take in order to maintain proximity with the actors.
Given the option, it is better to run long lengths of audio
cable (from receiver to recorder) than to have long lengths
of antenna cable (from antenna to receiver).
Virtually anything can interfere with good radio
transmission and cause bursts of static. Check for metallic
objects of any kind, such as jewelry, zippers, coins, and
keys. If you cannot eliminate the metal, then at least reposition
the antenna on the actor.
Carefully look at the path of transmission between
the actor and the receiver. Pay attention to lighting or grip
stands that may suddenly have appeared. A new influx of crewmembers
or spectators can also block the RF signal.
Examine the location itself. Check for additional
electrical lines, especially coiled feeds, which can generate
magnetic fields. Dimmers and special effects equipment (especially
neon) are always a problem. Motors can produce interference:
Be aware of golf carts, forklifts, camera cranes, automobiles,
and kitchen appliances.
Video and computer equipment can create strange
fields. Be aware of Steadicams and other camera mounts relying
on high intensity video or radio-controlled camera functions.
From:
Location Sound Corporation
http://www.locationsound.com
800-228-4429
Top of Page
Does the cable of the lavaliere microphone that
you have clipped to your subject's tie keep popping out from
behind the tie? Try running the cable through the loop formed
by the label that is sewn onto the back of the tie.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
If you work as a one-person video crew and need
to record audio delivered at widely varying volumes, Joe Salerno
of Bellaire, Texas, suggests running a normal audio level
on one track and setting a second track considerably lower.
(Most professional video recorders have more than one audio
track.) If the first channel peaks too high, you'll still
have a good chance of getting a usable signal from the backup
channel.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
Clear-Com
Communications
While I was working on a documentary recently,
the director asked me to record the chatter on the intercom
system. A check with Clear-Com, the intercom company, yielded
a schematic for an interface with a line-level recorder input.
Clear-Com warns, however, that plugging it into a microphone-level
input can cause problems with the intercom system.
The parts were small, and I was able to build
the entire unit inside a Switchcraft XLR3f-to-Phono male adapter.
From:
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
Wig tape is a very thin, double-sided adhesive
tape normally used -you guessed it - to keep wigs on people's
heads. But it is also handy for videographers. Mike Saxton
of Lutz, Florida, uses it to secure small lavaliere mics in
actors' clothing. He says the tape also keeps clothing layers
from rubbing against each other an making airborne noise that
could be picked up by the mic.
I've also found that a piece of wig tape will
keep an actor's wayward necktie centered an looking neat.
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
The most common kind of microphone is the handheld
type. This style is the most flexible, because it can be held
by the user, mounted on a floor or desk stand, or attached
to a flexible "gooseneck" on a lectern. A good quality
handheld mic should have an internal shock mount which will
minimize handling noise (thumping sounds transmitted through
the handle and picked up by the microphone cartridge), and
it should be ruggedly constructed to withstand physical abuse.
If you can have only one microphone in your kit of audio gear,
it should be a handheld mic. Models at the upper end of the
price scale will usually offer clearer, wider-range sound,
better shock mounting, and more durable construction.
Tips:
Whether held in the hand or mounted on a stand,
the microphone should be positioned about 6-12 inches from
the talker's mouth, pointing up at about a 45-degree angle.
With some types of microphones, holding the microphone very
close (3-6 inches) will cause additional emphasis of the lower
frequencies (known as proximity effect), resulting in a "warmer,"
bass-heavy sound.
From:
Shure - Guide to Better Audio
Written by Christopher Lyons
Top of Page
Another popular mic for video use
is the lavaliere type. Historically, the word "lavaliere"
refers to microphones which are hung on a cord around the
wearer's neck, but in recent years the term has grown to include
models which mount with a tie-clip, tie-tack, stick-pin, or
other similar arrangement.
Lavalier microphones leave the talker's hands
free to gesture, hold notes, or demonstrate a product. In
addition, they are usually very small and therefore tend to
"disappear" on camera. Also, using a lavaliere will
keep the distance from the microphone to the talker's mouth
fairly constant, reducing the need for frequent mixer adjustment
once levels have been set.
A disadvantage of lavaliere mics is the fact
that they tend to be "single-purpose" microphones
- they rarely sound good if handheld or used away from the
body. While the lavaliere mic's small size makes it easy to
conceal behind lamps or other objects, an equalizer is usually
necessary to make the mic sound "natural" when it
is not attached to the person talking.
Tips:
For best results, lavaliere mics should be clipped
to the tie or lapel at the breast pocket level. Try to avoid
placing the mic behind the tie or any material having more
than one layer-this reduces pickup of high frequencies, which
results in a flat, "muddy" sound. In addition, noise
from the movement of clothing against the mic or its cable
can be severe; experiment before risking the quality of your
audio track. On women, the mic may often be attached to a
stickpin or small chain with good results.
From:
Shure - Guide to Better Audio
Written by Christopher Lyons
Top of Page
These are microphones that are designed to work
on a flat surface. They are usually physically contoured to
look less intrusive on a conference table or desktop. The
microphone element is located very close to (but not touching)
the surface, which allows it to take advantage of the reflected
sound as well as the direct sound. This effectively doubles
the sensitivity of the microphone over a free-standing handheld
type at the same distance.
Tips: Surface mount microphones work best when
positioned on a smooth, flat surface, such as a table or desk.
If table vibrations are a problem, try putting a very thin
piece of soft foam rubber underneath the mic. In some situations
surface mount mics can even work well when mounted on a wall.
Keep in mind that the sound quality of this type of microphone
is affected by the size of the surface it is placed on. For
best results, use a surface at least 3 feet square; using
a smaller surface will tend to reduce pickup of low frequencies.
From:
Shure - Guide to Better Audio
Written by Christopher Lyons
Top of Page
The shotgun microphone is so named because the
long, slotted tube in front of the microphone cartridge makes
it resemble a shotgun. This "interference tube"
helps to reject sounds coming from more than about 30 degrees
off to the sides, while still picking up sounds from the front.
This extremely directional pickup pattern (called a Line/gradient
pattern) makes shotgun mics popular for TV news and on movie
sets.
Shotgun microphones are not "telephoto
Lenses" for sound. They do not allow you to "zoom
in" on a conversation from 100 feet away. Here's a much
more accurate analogy: imagine looking through a long tube
at a person standing 20 feet away. The person's image does
not appear to be any larger or closer, but it is somewhat
easier to see, because the eye is not distracted by things
happening off to either side. This is exactly what shotgun
mics do best - screen out sounds coming from the sides. You
can use this advantage in two ways: position the mic at the
same distance as you would a handheld mic, and enjoy clear
pickup of the source with very little background noise; or
position the mic farther away, and get the same amount of
background noise as the handheld microphone would have given
you.
Tip:
Shotgun mics can be positioned either slightly
above, below, or to the side of the sound source, so that
the mic does not appear in the camera frame. Try to avoid
moving the mic rapidly, since shotguns are sensitive to wind
noise, and use a foam windscreen if possible. Larger "zepplin"
or "blimp" type windscreens are usually necessary
outdoors. Also, it's a good idea to use a rubber-isolated
shock mount to minimize handling noise.
From:
Shure - Guide to Better Audio
Written by Christopher Lyons
Top of Page
When we record panels, we don't close mics because
we don't want to miss the first word of a speaker who suddenly
decides to chime in. But, as at least one former President
can attest, there is nothing worse than having an under-the-breath
comment heard by the world. To help prevent embarrassment,
Richard Johns, a freelance producer in Chicago, puts a note
in front of each participant that says, "Mics are live
at all times."
From: Dick Reizner
To share your tips for possible inclusion in his article in
Videography magazine, contact Dick at:
Reizner & Reizner Film & Video
7179 Via Maria, San Jose, CA 95139
dickreizner@worldnet.att.net
All submissions become the property of Reizner & Reizner.
None can be returned.
Top of Page
I recently had a carbon fiber boompole
crack at the end - not a pleasant occurrence by any means,
and rather than spend a lot of cash for a new section, I thought
to do a repair. I'm sure the folks at van den Bergh would
wince at the thought of what I'm about to describe, but here
goes:
The crack was just at the end,
past the hole the cable exits through after going through
the metal plug onto which the shockmount goes. A small piece
fractured off but was still hanging on. After talking with
a variety of others ranging from a very good (and thrifty)
soundman to a friend who does oddball construction (sets,
residential, and whatever) I came to the conclusion that this
would be repairable by someone like me.
I finally settled on marine epoxy
- very thick stuff meant to be used for hull patching and
plumbing work, among other things. The plug at the end of
the boom had ridges in its exterior that provided a good lot
of places for the epoxy to bond. Glopping a good but not excessive
amount on the plug, I pushed it back into the pole end. The
tiny fractured piece was replaced at this time.
Fiberglass filament packing tape
was cut to the proper width and tightly wrapped two or three
times around the circumference while the epoxy was still setting,
to compress and secure the fracture and provide reinforcement.
All this was allowed to set for two days.
Two days after, the plug felt solid
with plain hand manipulation, no movement whatever. To make
really certain, I put a small tie-wrap (non-releasable) over
the tape and pulled it tight.
I tested it with the Rycote in
place, and it feels rock-solid. Oh, I also got a small XLR
jumper to go from the 416 to outside the Rycote, so disassembly
of "Cousin Itt" is no longer required to dismount
the Rycote rig.
Alan Lloyd - Video Mercenary
alanlloyd@worldnet.att.net
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