Many of the basics of microphone care and maintenance are the same common sense techniques that apply to most other electronics: avoid high temperatures, moisture, dust, rough handling, etc. Other parts of care and maintenance, however, may contradict some of the common practices you’ve seen.
We have all seen someone blow into or tap on a microphone to test whether it is functional and turned on. This risks damaging sensitive electronic elements inside the microphone that pick up sound. The diaphragm inside a microphone is often a small piece of plastic which is only slightly thicker and more rigid than a plastic grocery bag. Tapping on a microphone risks rupturing this element which affects its ability to pick up subtle sounds. Just a small amount of moisture from blowing into the microphone can cause popping and other unwanted noise.
You may be familiar with the expression mic drop, which became popular around 2012. Wikipedia defines it as, "the gesture of intentionally dropping one’s microphone at the end of a performance or speech to signal triumph." The term is often used figuratively, but, as you might assume, actually dropping a microphone will make any audiovisual technician wince in pain.
Often, hand-held microphones, like the iconic Shure SM58, are designed for the rigors of live sound touring with features that make them extra rugged. Others, like Lavalier, Gooseneck, and Boundary microphones are much more sensitive and may perform poorly if roughly handled. No matter what kind of microphone you have, treat it like you would treat the most delicate item on stage. Even the toughest microphone will experience premature failure when not treated properly.
Cable management is another important element of microphone maintenance that may go overlooked. Always be careful where you place cables when they are in use and also how you store cables when they are not in use.
Placing cables where they will be stepped on will cause damage and, over time, this will negatively affect sound quality and cause premature failure. In addition, injury and equipment damage are possible if someone’s foot snags a cable causing them to trip. If possible integrate microphone cables into your performance or presentation area so that microphone cables can be plugged into connectors near microphone bases. Otherwise, cord/cable covers are available that will ensure that people can traverse cables without tripping over them.
Always coil cables loosely when they are not in use or if there is extra slack after running them for a live performance. This is especially true with delicate cables used with lavalier and head-worn microphones. Wrapping them tightly around receivers can cause them to fail prematurely. When these cables are integrated into the microphone element, it can be difficult and expensive to replace them.
For wireless microphones, batteries are an ongoing concern. When battery voltage is low, the connection between the transmitter and receiver can suffer, causing noise or total loss of sound. You should replace batteries frequently and always check date codes: just because a battery has never been used does not mean it is fresh.
Many wireless microphones now come with built-in, rechargeable batteries. Even these, however, must be replaced from time to time. Whatever battery your wireless microphone transmitter uses, be sure you know the best type.
Non-rechargeable batteries generally provide the most run-time. Among the different types of non-rechargeables, lithium batteries are the most powerful. They can provide more than twice the endurance of similar alkaline batteries. Depending on the type, rechargeable batteries can provide run-times that are comparable to non-rechargeable batteries. Most likely, your wireless microphone tranmitter will use AA or 9V batteries.
In AA-sized batteries, Nickel Metal Hydride (Ni-MH) types provide the best longevity. Compared to non-rechargeable alkaline batteries, Ni-MH rechargeables may offer more than twice the run-time. Compared to non-rechargeable lithium batteries, however, you can expect just 50% to 85% of the run time.
For 9V batteries, only Lithium Ion (Li+) batteries can offer the endurance of comparable non-rechargeables. The run-time for Li+ batteries is nearly identical to non-rechargeable alkalines, but less than half that of non-rechargeable lithium batteries.
Before settling on a battery type for your wireless microphone, check the transmitter’s user manual. Although batteries are packaged in uniform sizes (AA, 9V, etc.), the voltage they produce varies among the different formulations. Only use rechargeable batteries if the transmitter is designed for that type of battery.
If you would like to learn more about wireless microphone battery selection, the Shure Technical FAQ, Batteries & Wireless Microphones covers this in detail. In addition, we would appreciate the opportunity to answer any questions you may have any of the topics we discussed above.Download PDF