Getting the Best From Lavalier Microphones, January 1998 - Mixonline

Getting the Best From Lavalier Microphones, January 1998

EXPERTS SHARE THEIR TIPS
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Experts Share Their Tips

lav·a·liere, n. an ornamental, usually jeweled, pendant
on a small chain, worn by women about the neck. Named after the
Duchesse de La Valliere (1644-1710), mistress of Louis XIV of
France.

The lavalier (or lavaliere) mic is a special-purpose device, not
unlike a shotgun mic or hydrophone. And like those devices, the
“lav” has some sonic characteristics that restrict its
usefulness. However, though the lavalier mic is rarely a first-choice
mic for music recording, there are many situations in which the
advantages of small size outweigh sound quality considerations. For
example, though a well-positioned overhead microphone is usually the
ideal location sound recording tool, when the mic must be invisible to
the camera, a lav may be the only choice. Similarly, a well-positioned
rostrum mic will usually sound better on an “industrial”
presenter or motivational speaker, but the reality is that a lav is
almost always the production manager’s first choice.

Which is not to say that it’s always the sound mixer’s
first choice. A common refrain, whether on a Broadway show or on
location for a big-budget feature film, is that “lavaliers are a
necessary evil.” Well, they don’t have to be. This article
explains how to get the best results from lavalier mics in
less-than-ideal circumstances.

SELECTING MICS
When selecting a lavalier mic, most of the P.A. rules of thumb apply:
Gain before feedback and a flat response are primary considerations
(fortunately, these two characteristics are usually complementary).
Coverage pattern is also important, though even the most hypercardioid
lavs tend to be far less directional than larger-format mics.

If you are renting lavs, try to stick to one model; mismatched lavs
can result in impossible situations, especially when there are several
lavs and a P.A. feed in the same room. An exception to this rule is
when a particular mic model accentuates an unwanted timbre or
sibilance.

Accessories can make the microphone. Ask your dealer what
accessories are available and buy extras—when you are on location
and find that you need more mics than you have, the extra clips make it
feasible to pre-rig several locations and switch mics around quickly.
Plus, you can now afford to lose an accessory, which is all too easy on
a busy set.

In general, stick with the manufacturer’s supplied mic clip or
windscreen; a substitute “universal” clip rarely works as
well as the original. Also, compromised mic-mounting solutions tend to
fail in the middle of a live feed, leading to stress on the
mic-to-cable connection (not to mention stress on the
director-to-sound-recordist connection). A warning: Don’t
temporarily store accessories in your pocket. They all seem to start at
a replacement cost of $30, and if you walk off the set with a pocketful
of accessories, that can take the profit out of your whole day.

POSITIONING AND SECURING
The all-round best spot to aim for in hiding a miniature mic is just
above the sternum or breastbone. The resonance of the chest cavity
sounds much better than when the mic is positioned at the throat area.
Often, a vampire clip to hold the mic inside the shirt, touching the
skin, is all you need. Layers of clothes and physical action can spoil
this setup fast, but if you place the mic to favor the head turn (if
there is one in the shot), this placement often does the job.

Warning! When using a metal-bodied mic next to the skin, be sure
that your power source is grounded properly (especially if it’s a
generator) and that all cables are wired correctly. A wet field,
leather-soled shoes and a truck generator in combination with a
hard-wire lav can make your star anchor do the “You’re
fired!” dance.

To hide a mic in or under clothes, choose a mic with a recessed
grille, rounded edges and an LF roll-off characteristic. “On
collars and ties, I like to hide the lav in the tie knot,” says
Pete Verrando, C.A.S., a freelance production sound mixer in Dallas for
the past 12 years. “The perspective is pretty forced, but the
clothing noise is really minimized. Suits make tons of clothing noise.
I usually tape the tie to the shirt, as well. I wrap the lav in toupee
tape before concealing it in the tie knot.”

Once the mic is hung and dressed, the next few inches of mic cable
should be loosely looped into an overhand knot, then strain-relieved at
the nearest belt or collar. This is the little-known 9dB knot, so
called because the nature of the loop and knot allegedly reduces noise
by 9 dB. Hey, it works.

Successfully positioning a lav mic often necessitates a rather
intimate relationship between the sound engineer and the performer.
Sometimes actors and models are asked to work in cold environments, yet
are costumed as if for a heat wave. A cold-metal sound component
against the back can be just the thing to trigger very unphotogenic
goose bumps; so, after you battery-up your transmitters and preamps,
store them in your pocket for a while.

When your job involves shoving your arm under somebody’s
clothes, tact and consideration are extremely important. “I
don’t get much hassle from actors when futzing with their
clothes,” says Verrando. “I tell them what I’m going
to do first, and then get them to help me string the wire through the
clothing. It helps to kind of narrate the process as it’s
happening.” This goes double for high-power CEOs. These days,
most are pretty media savvy, but if you’re on their turf, watch
out! Confidence and politeness in these situations are essential, and
don’t forget those breath mints!

Make friends on the set or backstage. Wardrobe and hair people can
help you immensely or, intentionally or not, make your life miserable.
They can make useful accessories like mic belts, which can help hide a
radio transmitter when a dress has no pockets. Hairdressers can help
you with a good head mount that positions the mic in a hat, wig,
glasses, mask or hair. A good head mount is hard to beat; the proximity
can be excellent, the skull resonates nicely, breath pops are
eliminated, and head turns are not a problem. Make sure you have proper
strain relief, and keep the wire invisible at the neck. In the case of
a dancing performer, take extra care with strain relief.

Wardrobe can also provide you with integral mounting as part of a
costume and quick solutions to clothes that rustle. Everyone has an
opinion on which fabrics make the most noise, but most problems seem to
come from layers of different types of clothing rubbing over each
other. Starched or stiff clothes tightly worn are also noisy, as is
contact with the windscreen, body or cable of the microphone. A few
quick passes with needle and thread can often eliminate such
problems.

Nevertheless, some wardrobe choices are bad news for the sound
person. Jewelry, running suits, corduroy and plastic fabrics can all
cause problems and should be tested for sound in an air-conditioned
trailer, rather than on the set. Better yet, convince the director that
you should attend wardrobe pre-production meetings.

“The main thing about body mics is letting the [assistant
director] or who-ever is in charge know that sound needs some time to
wire actors,” says Verrando. “On crazy shoots, when in
doubt, wire ’em and it’ll be there if you need it. But
it’s good form to let all involved know what I’m doing. It
also trains the crew chiefs to occasionally expect a little sound setup
time.”

TOOLBOX TRICKS
Every sound pro carries a comprehensive spares kit and toolbox, but you
will need a few more items for lav mics. It’s extra stuff to
carry, but if you hang up the production while you fabricate and
perfect an improvisation, you may not be hired again.

A few thoughts about adhesives. Gaffer’s tape, toupee tape and
moleskin should be chosen carefully and used wisely. Residues can fill
in microphone windscreens and may gunk up the diaphragm. Never store
mics with tape still on them. Camera tape and paper-based tapes are bad
choices. Try waterproof adhesives like surgical tape; good, fresh
gaffer’s tape is always hard to beat. Most of the rest of the kit
resembles items from the hairdresser’s kit, but have the items on
hand anyway.

SMOOTH OPERATION
Lavaliers require maintenance, just like any other piece of pro audio
gear. In normal use, there is very little that can go wrong with a lav
mic, but heavy use and wet conditions should inspire cautious
preventative maintenance. Molded connectors should be visually and
operationally inspected, especially after a good yank on the cord.
Don’t lose your chance to identify the problem before the mic is
stored with its twins. Fastener-assembled connectors are notorious for
coming unscrewed, so make sure you have the right screwdrivers on set.
Make sure all your fasteners are well-seated, but not too tight. Watch
for corrosion build-up or dirt in the contacts.

Moisture is the enemy, sweat is the worst. Joe Pino, resident sound
designer at the Tony Award-winning Alley Theatre in Houston
since 1990, recommends the following for sweat-outs:
“There’s nothing you can do after it happens, as far as I
know. Let them dry out and see if they start working again—after
a few days, Pow!, there they are like nothing ever happened.” In
desperate situations, try storing the mic in a zip lock with some form
of sealed desiccant. As a preventative step, Pino recommends spraying
or dipping new mic windscreens in Scotch Guard and then immediately
blowing the mesh out with canned air.

Windscreens are often necessary outside, but they are not
“rain screens.” “Lately we’ve been leaving the
windscreens off—the windscreen seems to actually wick the
moisture into the capsule,” says Pino. “We still use
moleskin or Elastoplast occasionally as a cover and moisture barrier,
especially if the mic needs to be colored to match make-up. It really
depends on the performer and the application.”

A particularly important point to consider is battery power,
including electret batteries, battery-driven phantom supplies and
transmitter packs. Pino recommends checking the latest Consumer
Reports
battery tests to see how the various manufacturers’
models stack up. Such articles usually include an informative treatise
on different battery compositions. The major point to note is that as
voltage goes down, the noise floor seems to rise, the output is reduced
and gain before feedback is reduced. The preferred type of battery
starts with a high sustaining voltage that drops off sharply, rather
than gradually. Never compromise on batteries, and properly dispose of
them immediately to prevent reuse. No matter how much the producer
whines about budget, just remind him that cameras need light and sound
needs batteries. Never accept rechargeables.

EQUALIZATION
And when you’ve wired the actors and are set to record, please
remember: Critical EQ decisions are often better left to
post-production! The watch word is consistency. In live situations,
radical EQ settings chosen to favor one voice can leave other
actors’ voices too thin. Further, radical EQs will not cross-cut
well against the “average” EQ setting. Make sure to record
some ambient room tone while you still have everyone wired.

In order to reduce noise from handling, clothes, ambience and breath
pops, a low-cut (bass roll-off) EQ is allowable. High-frequency EQ
should only be added in cases where intelligibility is being lost, such
as when the mic is obscured by thick clothes. Unnecessary use of HF EQ
can result in too much sibilance, especially in a wireless/Nagra
combination. In such situations, another mic placement or another type
of mic, such as a shotgun, will often yield better results.

Properly used, lavs can provide an elegant solution to many modern
sound design problems, and they can often be used in conjunction with
other mics to improve overall sound quality. “I often use a lav
to help clarify a line in a boomed scene,” says Verrando.
“When a scene is great on the boom except for a line or two,
I’ll sneak the lav in the mix to perk up those lines. A scene
doesn’t have to be all boom or all lav.” Don’t be
afraid to experiment, and give yourself time to use the best test
equipment in your rig: your ears!

PREPPING MICS THE ALLEY WAY(courtesy of Joe Pino)
1. Power up the pack.
2. Quick vocal check (“One, two, testing”).
3. PFL in cans, work the entire length of the cable, looking for
continuity faults, especially at the connector.
4. Second vocal check.
5. Repeat for next mic. Note: Once mics are turned on at the console
by the engineer, they should never be turned off. If you try to save
batteries by leaving them off for a late power-up, you’re
courting disaster.

6. After check, which should be as late as possible (keep the batteries
fresh), the mics should go straight to the performers.
7. In long shows, it’s not a bad idea to change batteries at
intermission.

Pino claims that, thanks to these procedures, he has mics over seven
years old that are still in fine condition!

LAVALIER TOOL KIT ESSENTIALS
• Small rolls of gaffer’s tape, toupee tape,
medical/surgical tape
• Vampire clips, tie-tack clips, button-hole clips
• Extra batteries
• Foam windscreens, cheesecloth windscreens
• Velcro body-pack holders
• Zip-lock bags and a sealed desiccant package
• Battery-powered shaver (used to prevent “five
o’clock shadow” noise on the collar)
• Breath mints (self-explanatory)