Wireless Microphone Systems: An Introduction
Wireless microphones have been gaining popularity over the past number of years because of their sound quality, reliability, and improved cost. This guide is designed to give you a basic understanding of how these systems work, as well as help you decide which wireless microphone package is right for your needs.
Why Go Wireless?
The greatest benefit of a wireless microphone is the freedom. These systems eliminate the need to have a cable running from the mic to your setup. This allows you to move around your stage without worrying about coming unplugged or tripping over excess wires. In general, one wireless system replaces one standard wired system in a setup.
How Does Wireless Work?
A standard wireless system will feature an input device, a transmitter, and a receiver. The input device produces the sound that is sent to the transmitter, which in turn handles the conversion of the audio signal into a radio signal.
Transmitters are usually offered in a “body-pack” style, which is a small box about the size of a compact point and shoot camera connected to your belt or body, or, for instrument applications, connected to the instrument itself. Additionally, in the case of wireless microphones, the transmitter can be built directly into the mic. Transmitters all require a battery to operate and can usually send signals from 100 feet to over 1000 depending on the conditions in the environment.
Receivers are responsible for turning the radio signal broadcast by the transmitter back into an audio signal. Because a receiver’s output is electrically identical to a standard mic signal, it can be connected to a soundsystem’s microphone input. Wireless receivers are offered in single antenna and diversity configurations. Single antenna receivers are similar to FM radios, using one receiving antenna and one tuner. They work well in many environments, but are prone to momentary interruptions depending on where the person wearing the transmitter is standing. Diversity receivers, on the other hand, use two separate antennas and, often times, two separate tuners. The with two signals being received, an “intelligent” circuit selects the best one, or even blends both options, ensuring the signal is clean at all times and doesn’t drop out.
If more than one performer or presenter is using the wireless system at a particular location, each must use a different frequency. This is because wireless signals cannot “share” frequencies without serious interference. Think of it as if two television stations were trying to broadcast on the same channel. Because of this fact, there is always going to be a limit on the number of systems that can be used at one venue.
Which Wireless System is Right for You?
Choosing the wireless system that will work best for you really comes down to what your specific needs are as an artist. For example, your input device and transmitter will be chosen based on the source you will be micing. So, if you’re a vocalist, you’ll probably want a handheld mic/transmitter; if you’re singing, but your hands are occupied or you’re also dancing, you’ll want a headwornmic and a bodypack transmitter; if you’re playing a horn, you’ll want a clip-on mic and a bodypack transmitter, etc. Making sure you have the setup that is right for your needs is the first step to a successful wireless system.
Choosing the right mic for your system is a similar process to choosing any other mic. You need to take into account how you’ll be using it and the environment. The mic being wireless does not change the fact that you will need to consider pickup patterns, frequency responses, and other technical aspects.
Choosing the type of receiver you need comes down to environment most of the time. Single antenna systems should be used in environments where the operating distance is short and the space is not prone to dropouts. Diversity systems should be used in larger spaces, spaces where the signal may have to travel through walls and doorways, or environments that may be prone to radio frequency interference.
How Does the Wireless System Connect to the Sound System?
As mentioned earlier, almost all wireless receivers emit a signal that is electrically identical to a wired mic, so the receiver’s output jack can simply connect to the same input jack where a wired mic would connect. If your system revolves around a guitar, a short cable will connect the guitar to the transmitter, which transfers the sound to the receiver, which is connected by a wire to the input jack on your amp.
Each wireless system in use must be connected to different inputs on the sound system. This is so each microphone can be adjusted independently, taking into account each user may be singing, talking, or playing at different volumes. Depending on the type and number of connections your sound system has, you may need an adapter cable to ensure everyone is properly connected to the interface. These adapters are easily found at your local wireless system dealer.