You are here: Home Page » Audio » Making mics last

Making mics last

May 1, 2009 12:00 PM, By Steve Savanyu

Microphones are an investment. With a little care, that investment can pay off for many years.

You can improve the performance of dynamic microphones, such as the AE4100 from Audio-Technica shown here, simply by removing the headcase and cleaning out the debris.

Our journalistic hero, caught in a bind on location, needs to pound a nail. No hammer in sight, he pulls out his trusty handheld interview mic (complete with station ID flag) and, like “MacGyver,” quickly seats the offending nail, just in time to complete the interview and boost station ratings. We have all heard these stories, and although some microphones are fairly rugged, we would stop short of using one as a hammer.

In reality, a microphone is a precision instrument that, with a little care, can last many years. Today, broadcasters use many different types of microphones. Two of the most popular are dynamic and condenser.

Dynamic microphones

Dynamic microphones are a prevalent choice for handheld interviews, live vocals and some air studio uses. Characterized by their large physical shape, these inherently rugged microphones will take most of the abuse a field correspondent can dish out. The biggest issue with dynamic handheld mics seems to be with headcase grilles getting clogged and damaged. Simply removing the headcase, cleaning out the debris and replacing it can improve performance. Plus there's the hygiene factor: Cleaning the grille can help prevent the spread of germs. An external foam windscreen is also useful for protecting the headcase.

Don't overlook the microphone's connector. Over time, the connector insert may come loose with repeated use. Simply tightening the small setscrew that that holds the connector in place will do the trick. Because the threads in the insert are reversed, turning the screw to the right actually backs it out of the connector insert, securing it to the microphone body. A technician's “greenie” screwdriver is ideal for this task.

Condenser microphones

Condenser microphones with their extended response, low handling noise and ability to be miniaturized are commonplace on set and location. A far cry from the neck-worn lav mics of the last century, the new breed of subminiature lavaliers are practically invisible on camera and can outperform the best dynamic mics. Although these microphones are quite rugged, a little common-sense care can extend their lives. Here are some tips to make them last longer.

When using wired lavalier microphones, attach the power supply/module to the wearer with the power supply's clip. This keeps the strain off the smaller lav cable should the wearer decide to get up and walk with the mic. Store the mic with its cable coiled in a protective case, and resist the temptation to coil the mic and cable around the radio-mic transmitter pack. When wearing a radio-mic transmitter, secure the mic cable under the transmitter belt clip to take strain off the connector.

Some lavalier microphones come with an accessory kit that includes small “makeup caps” designed to slip over the microphone capsule. These are used to keep theatrical makeup from clogging the small element opening and damaging the mic. They also work well to keep other debris out of the mic and can be easily removed for cleaning with rubbing alcohol and a cotton swab.

Remember the “broadcast loop” technique for dressing a lav mic cable on a clothing or tie clip. (See “The broadcast loop” sidebar below.) Besides helping to minimize the pickup of mechanical sound transmitted up the wire, this helps lessen cable strain on the mic.

All condenser microphones require power to operate. Typically, this power supplies energy to a small amplifier circuit inside the microphone, although some condenser microphones use it to put the electrical charge on the capsule's backplate. Depending on the situation, this power can come from a microphone's built-in battery or up the microphone cable in the form of phantom power provided by the mixer, camera or an outboard power supply.