Wireless Microphone

A wireless microphone, as the name implies, is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated. More commonly known as a Radio Microphone, there are many different standards, frequencies and transmission technologies used to replace the microphone\'s cable connection and make it into a wireless microphone. They can transmit, for example, in radio waves using UHF or VHF frequencies, FM, AM, or various digital modulation schemes. Some low cost models use infrared light. Infrared microphones require a direct line of sight between the microphone and the receiver, while costlier radio frequency models do not. Some models operate on a single fixed frequency, but the more advanced models operate on a user selectable frequency to avoid interference, and allow the use of several microphones at the same time.

Advantages: 

•  Greater freedom of movement for the artist or speaker
•  Avoidance of cabling problems common with wired microphones, caused by constant moving and stressing the cables
• Reduction of cable \"trip hazards\" in the performance space

Disadvantages:

• Sometimes limited range (a wired balanced microphone can run up to 300 ft or 100 meters). Some wireless systems have a shorter range, while more expensive models can exceed that distance
• Possible interference with or, more often, from other radio equipment or other radio microphones, though models with many frequency-synthesized switch-selectable channels are now plentiful and cost effective
• Operation time is limited relative to battery life; it is shorter than a normal condenser microphone due to greater drain on batteries from transmitting circuitry, and from circuitry giving extra features, if present
• Noise or dead spots (places where it doesn\'t work, especially in non-diversity systems)
• Limited number of operating microphones at the same time and place, due to the limited number of radio channels (frequencies)