One of the things that makes wireless microphones so great is what they don't have - wires! Working wireless gives artists with elaborate stage shows, like Pink, true freedom of movement on set. But as awesome as wireless mics are, they are not without issues. In this List, we'll discuss five common glitches that you might experience with wireless microphones (and their receivers) and how to fix them.
One of the most common problems with wireless mics is signal blockage. A wireless mic is a transmitter, and anything in a wireless set-up between the transmitter and the receiver can block the signal. The typical culprits are walls or solid/dense objects on set, so you may need to move your receiver, or your external antennas if you use them, around to find a line of sight path for the RF signal. The human body can also absorb signals, which can be problematic for belt-pack units if not placed carefully. Same goes for handheld mics: make sure that they are being held properly so that the antenna is not covered by the hand. We explain this in more detail in Wire List #8.
Bodyworn transmitters, such as you'd use with a lavaliere mic, depend on their antennas - that covered wire extending out - to deliver a signal. If the antenna is obscured or bent, your signal will be affected. Repeated stress, such as bending an antenna in the same spot, will break the tiny wires that make up the inner core of the antenna and render them useless over time. Our antennas are quite tough but with enough abuse, they can fail. Our transmitters have fixed-length antennas for specific frequency ranges, so always ensure that your antenna matches your frequency. We color-code ours to make it easy. If you are finding that your range is inadequate, consider using a directional or omni-directional antenna to boost the range. We offer several options depending on your specific need, and you can also make your own.
“Static” in the audio can be created when mic connectors are worn out, damaged, or corroded, or if there is moisture in the connector. Any movement can then create noise which is then transmitted. Be sure to keep your connectors clean, and if the metal parts become worn or the fit isn’t what it once was, consider having the connector replaced. We cover connector cleaning in Wire List #5.
Accidental Setting Changes
Have you ever synched your mic, only to find that it changed settings again somehow and now isn’t syncd? Settings are often sent via IR, where the "window" of the transmitter is exposed to the emitter on the receiver. Usually, the range of these IR emitters is only a foot or so, but in just the right conditions, the reach might be further. To prevent this from accidentally changing the settings on one of your units, simply put a piece of tape over the IR window after you've synched. This will "lock" the setting and make sure that no other signal can change it. Just remember that the tape is there next time you use it! Tape is also useful for power switches. While our handheld has the power switch behind a sliding panel, other manufacturers have it where it can easily be toggled. A piece of tape prevents the switch from being accidentally bumped to the off position.
Interference and Intermodulation
If you are using Frequency Finder or another program to scan and choose your frequency, you may never experience interference. However, in today's crowded airwaves and when you are using multiple systems, it’s a possibility, in which case, you simply need to change your frequency for the affected units. Try switching your mic/receiver 2-4 MHz (do it in steps) up or down from where you were. Intermodulation, which we discussed in last week's Wired List, is when two or more frequencies interact, create new signals, and cause potential interference. You will frequently see this in large productions, when you have ten or more mics operating in a relatively small (frequency) space. Like too many people in one room that make it hard to hear conversations, intermodulation can be corrected by calculating for these interactions and planning your frequency occupation carefully among your connected units. This is an ideal use for Wireless Designer as you can see and keep track of all of your connected systems on one page. As you can see, most of these problems are easily diagnosed and just as easily repaired without needing assistance. Still stumped?