Obviously wireless microphones have some major advantages over their wired counterparts. Most notably is that it does not need a mike cable in order to connect it to the mixer. Instead, the signal is broadcast by a low-power FM radio transmitter to a receiver and subsequently fed into the mixer.
Wireless microphones seem like the perfect answer, so why doesn’t everyone always use them? It looks like a sound designer’s dream solution! Unfortunately, however, like all things, there are drawbacks. One of which is the problem of batteries dying. The batteries that power the microphone transmitter have to be checked, and usually changed, for every performance.
Another drawback is that since the signal is broadcast, the receiver is also subject to receiving other types of transmissions besides the ones that are wanted, including many types of interference. Most theatres are in moderate to large cities, and in these areas it is not uncommon for the wireless microphone receivers to pick up local radio stations as well as the microphones.
Yet another drawback occurs when using more than one wireless microphone in the same production. Each microphone being used needs to transmit on a different frequency so that the sound operator can monitor the individual performers. In a typical production there are usually three to five leading characters which need to be equipped with wireless microphones.
Another major drawback is the price. A wireless system is very expensive. A good-quality wireless microphone, which will transmit and receive within a very narrow frequency range often costs between $1,000 and $3,000.
The wireless microphone, despite the many drawbacks, is an excellent method of miking a show. The challenges outlined here can be overcome in most cases. The wireless microphone is probably the best known way of reinforcing the voice in a theatre. The presence that is attained with this type of mic placed close to the actor’s mouth can be matched only with a hand-held microphone. It would seem quite out of place in most theatrical productions to have characters walking around carrying microphones. There are no other theatrical reinforcement systems that even come close.