The lavalier is probably the most frequently used microphone in any videographer’s kit. Once the size of a salt shaker and hung by a stout cord around the neck, like the jeweled pendants worn by a French duchess named La Vallière, these ubiquitous mics are today small enough to be inconspicuously clipped to – or hidden beneath – the wearer’s clothing.
Lavs are the mic of choice for standups because they leave the hands free and, as they remain a constant distance from the reporter’s mouth, provide a fairly constant audio level. Practically a requirement on interviews, lav mics don’t intrude on the picture, are less intimidating than a hand mic stuck in the subject’s face, and allow wide latitude in composition as the interviewer can be positioned out of frame.
Care must be taken when attaching a lav that scarves, jewelry, and the wearer’s hair will not come into contact with the capsule. Beware of anyone with shoulder-length hair. Brushed back at the beginning of the interview, long hair will jump over someone’s shoulder and onto the lav the first time they turn their head. The mechanically induced sound of something touching the mic will ruin the recording.
Always consider the direction the subject is likely to turn their head when mic-ing an interview. Position the lav on the lapel nearest to each person’s conversation partner or in the center or the chest if they are in the middle of a group. This prevents going “off-mic” if the head is turned away from the side on which the lav is positioned.
Taping the cable to the underside of a subject’s sweater or jacket will help prevent the mic from being dislodged by an accidental tug on the cord. Making sure there is plenty of slack when someone tucks a cable under their belt or waistband is another way to prevent mishaps. The simple act of leaning back or crossing a leg while seated can pull an improperly attached lav out of place. A guest on an interview show almost brought the taping to a halt when, unaware that she was on-camera, she began trying to retrieve mic that had become dislodged from the top of her blouse.
Interviewees should be frisked for mobile phones before the interview begins. Turning off the ringer does nothing to prevent the phone from periodically checking in with the cellular system. The RF generated when a mobile phone acknowledges messages or queries from the carrier is readily picked up by a lav. This all too common problem even affected an extended sit-down interview with President Obama that aired on a major network.
Finally, remember that lavs don’t always have to be fastened to a person to prove their worth. A lav can be taped invisibly to a podium when there is neither a mult-box nor space for a mic stand, or to a telephone handset so you can record the person on the distant end of a conversation. Covered with a block of sound-deadening material and taped to the earpiece of an aviation headset, a lav will even let you record a standup or interview in the high-noise environment of a helicopter via the noise-cancelling mics that are part of the aircraft’s intercom system.