Wireless mics (microphones) have been around our industry for about 30 years now, with the earliest models dating back to the late 50’s. So much has been written about these extremely useful tools. We use wireless technology in virtually all forms of PA (Public Address) systems. They are especially helpful to those speakers who like to have total free movement about either a stage or auditorium.
Wireless does come with its own set of rules. Primarily, the 1 to 10 rule. That is, for every dollar spent on a wired mic 10 dollars will need to be spent on a wireless mic to have a similar sound. That said it is better for a band or singing group to use wired mics based on cost savings, overall reliability, and sound quality. You should plan on spending a minimum of $100 per wired mic and a minimum of $450 per wireless channel. (Keep in mind that the $100 wired mic will sound significantly better)
Wireless mics come in many varieties, like a standard hand held unit-which is preferred by many performers- as it gives them the ability to alter their levels according to their singing or speaking. This style is also preferred by groups who want to pass a mic easily between a variety of speakers. When you watch a professional performer using their hand held mic (wireless or not) you will see them use it very close to their mouth, for best overall level without feedback, or moving the mic away for effect or sound level fades.
Head worn or Countryman style (over the ear) mics which have a small mic or tube which extends up to near the performers mouth is preferred by active performers who want no hand restrictions for dance or to augment their speech or to sing with movements.
The down side of these is not being able to remove them quickly for a slight cough or throat clearing. Depending on your needs it is wise to think long and hard about how it will be used.
Shure builds a great variety of both wired and wireless mics. Shure is one of the oldest and most respected of the manufactures of these devices. Other notable brands include AKG-Acoustics, Sony, Audio-Technica, and Sennheiser. Shure builds about five grades of wireless mics and even more grades or styles of wired. Shure also builds- in the less expensive lines, dual channel wireless receivers so that you might have one hand held and one worn mic both being delivered to a single wireless receiver. They also sell units which are dual channel and they come with 4 wireless mics (2 hand held and 2 wireless) –only 2 mics can be used at a time however, one mic only per channel. These types of mics need to be clearly marked to keep only one mic per channel. This allows for many types of performers and performances needs, to be addressed with minimum of expense.
Many institutions use a variety of mics which all feed into a mixer and can be controlled by a technician for level and equalization. A good rule of thumb on equalization is to always employ the LF (low filter) or sometimes called HPF (high pass filter). This filter will effectively block all sound below 80 Hz or there about. There is no need in common mic applications to hear sounds in the below 100 Hz range or above the 10-13 kHz on the top end. 20-20KHz on a mic input will get runaway feedback so it is often wise to use the input equalization which is on most all mixers to limit the input frequency response with sharp cutoff filters, leaving only a range of about 100-8kHz for a male speaker and perhaps 150-12kHz for a female.