Using Microphones With Wireless

Although modern microphones are rugged and reliable, they can fail if abused, mishandled or subjected to damaging conditions. In addition, heavy use and the accumulated effects of normal wear and tear will eventually result in performance loss or failures. With reasonable care and some simple precautions, the useful life of a microphone can be greatly extended.

Because of the way that they are used, handheld transmitters are subject to being dropped. Their shape also allows them to roll off of tables and desks, increasing the chances that they will eventually suffer a fall. Both the microphone element and the transmitter electronics can be damaged by a fall, but electronic failures tend to occur slightly more often than element failures. Although a short drop is not likely to cause failure, drops from greater heights will increase the chances of damage.

Even if the microphone element does not fail, repeated drops can eventually affect sound quality. The shock caused by drops can also disturb the adjustments in the transmitter electronics, possibly resulting in reduced range or poor audio quality. After a handheld transmitter has suffered a hard drop, it is wise to listen carefully to the wireless system to make certain that the sound quality has not been affected. A range test is also worthwhile.

Because of their shape and the way they are typically used, wireless body-pack transmitters are less likely to be dropped. Their lower weight also tends to reduce the chances that a drop will result in a failure. Hard drops, however, can sometimes damage the microphone connector, especially if the drop occurs while the microphone is plugged in. The lavalier microphones themselves are very light and are almost never damaged by being dropped.

The miniature cables used with lavalier microphones can be damaged by pulling, stretching, sharp bends and repeated flexing. Most cable failures occur where the cable enters the connector or the microphone body. Generally, a cable break near the connector can be repaired by shortening the cable by 2 inches (5 cm) or so, at least until the cable becomes too short to be usable. Extra care in avoiding sharp bends and excessive flexing, especially near the microphone itself, will pay off in longer life and fewer problems. Eventually, however, a microphone cable simply wears out and can no longer be used.

In certain applications, such as aerobics instruction and the musical theater, it is unavoidable that the microphone cable is subjected to constant flexing. In these circumstances, selecting a microphone with a slightly larger and stronger cable should be considered. It is always a sensible idea to have a spare microphone on hand, especially for applications of this type. In addition, microphone life will inevitably be shorter than for less stressful uses, and the cost of replacement microphones should be factored into the budget.

Unless appearance is of prime concern, the use of foam windscreens is advised for handheld wireless transmitters. Although the foam does not offer much protection from drops, it does greatly reduce wind noise and voice "pops." The foam also helps protect the microphone element from moisture and keeps the metal grille windscreen clean. Foam windscreens are less necessary for lavalier microphones unless wind noise is a problem or conditions are very wet.

Foam windscreens should be washed frequently and air dried. When it is no longer possible to wash the foam clean, the windscreen should be discarded and a new one installed. Unless a foam windscreen is always used, the metal windscreens on handheld microphones should be inspected frequently and washed when necessary. Lipstick, makeup and dried saliva tend to clog up metal windscreens, as well as the internal foam windscreen, if one is used. Over time, the output and sound quality of vocal microphones can gradually degrade unless the windscreen is kept clean.

Severely dented metal windscreens should be replaced. The dents can allow the mouth to come too close to the microphone element, increasing pop noise and changing the sound of the microphone. The internal foam windscreen, when one is used, can also be pushed into the element, muffling the sound and affecting microphone performance.

Microphones and wireless transmitters and receivers should be protected from moisture. Although modern microphones are not particularly sensitive to the environment, moisture or excessively high humidity can cause corrosion and other problems, affecting both microphone elements and electronic circuits. Unless necessary to protect from high humidity, microphones and transmitters should not be stored in plastic bags or sealed enclosures after use, at least until completely dry. Always air-dry the equipment after use to allow water, perspiration and saliva to evaporate, rather than trapping it inside the equipment.

Condenser microphones should be protected from excessive humidity and long term exposure to high temperatures. Either can permanently degrade sensitivity and sound quality over a period of time. Perspiration is particularly damaging because it is corrosive, leaves harmful chemical residues and attacks condenser microphone elements with moisture. When performers perspire freely, it is highly advisable to protect the microphones from direct exposure by using foam windscreens or protective plastic covers.

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