Awireless microphone, as the name implies, is amicrophonewithout 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 wirelessmicrophone. They can transmit, for example, in radio waves using UHForVHFfrequencies, FM, AM, or various digital modulation schemes. Some low cost models useinfraredlight. 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 XLR 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)