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.
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.
Even though the batteries will last in excess of 1000 hours of operation, when using battery-powered mics, make certain the batteries are fresh, especially for that critical production.
For microphones that require it, verify that the phantom power is switched on. I have been on locations where time was spent troubleshooting bad mic cables, only to discover that the phantom power was turned off at the mixer. When turning phantom power off or on, and when connecting or disconnecting condenser microphones, turn the input channel's level down to avoid nasty “pops” in the audio system.
Because the backplate and diaphragm in a condenser mic are charged (think capacitor), condenser microphones are more susceptible to moisture than are dynamic mics. When used in situations with high humidity, there is a chance that excess moisture on the diaphragm may cause sizzling sounds similar to bacon frying to be heard from the mic. Simply let the microphone dry out. Put a bowl of uncooked rice in a closed box with the mic to absorb moisture. Protect air-studio mics from excessive mouth moisture with a good pop filter or foam windscreen (also good for mic hygiene). Another way to extend the life of your production studio microphones is to cover them when not in use.
In extremely damp locations, consider protecting the microphones with an impenetrable moisture barrier. Yes, the lowly unlubricated condom works wonders for keeping moisture out without too badly affecting the response and pickup. During a recent Winter Games, more than 400 of these impenetrable barriers were sent to the site to protect shotgun mics from snow and ice.
A shotgun or rifle mic is shaped like a long narrow tube with a series of slots down the sides. Protect these mics by storing them in their manufacturer-supplied cases. An alternative storage method is to keep the mic (with its foam windscreen attached) inside a piece of PVC pipe the same diameter as the mic/windscreen and loose capped at both ends. Just remember not to carry these through airport security.
Another thing to consider when using phantom-powered mics is the mic cable. XLR connectors will wear out with continued plugging and unplugging. Sometimes they become intermittent, disrupting phantom power and causing all kinds of noises. Make it a practice to regularly check and maintain your cables and replace worn connectors as necessary.
Finally, if you find that your expensive studio mics just don't sound as good as they did when you bought them, consider sending them back to the manufacturer for a tune-up. Many manufacturers can provide this service. Often a good cleaning and adjustments by the service tech can restore a microphone back to factory specs, adding many good years of life to your mic.
Microphones are an investment. With a little care, that investment can pay off for many years.
Steve Savanyu is director of educational services for Audio-Technica.
The broadcast loop
Proper dressing of a lavalier microphone's cable can help minimize cable noise. This technique, called the broadcast loop, is one way to do it. Start by mounting the microphone in the mic clip. Make a small loop with the cable below the mic, and secure the cable to the clip.
Thread the cable up, around and back down behind the clip securing the cable between the fabric and back of the clip. Note that the cable goes down behind the loop. Finally, dress the cable under the wearer's clothing, out of sight.
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