Cordless headphones allow the wearer to move freely without restraint of a cord while listening to a home stereo, television or other electronic audio player. The devices also free the listener from having to carry a portable audio device. Incidentally, cordless headphones are more commonly called wireless headphones, but the terms are synonymous.
Cordless headphones operate over a radio frequency or with infrared technology. Both technologies rely on a base station, or source transmitter, which is connected to an audio source that has a headphone jack or stereo RCA output. Headphones have a built-in receiver and amplifier. The signal is received in the form of radio waves and the amplifier converts them into sound waves into a pair of tiny speakers. Cordless headphones use batteries in order to power the receiver and amplifier. When not in use, devices with rechargeable batteries are docked on the base station for recharging.
Cordless headphones that use radio frequency (RF) technology operate like cordless house phones in that the radio waves, or signal, can penetrate nonmetal walls. This allows the user to move throughout the home, provided they remain within range of the base transmitter, which runs between 100 and 300 feet, depending on signal strength. Radio frequency usually provides a robust signal, and thus good audio quality when unimpeded. However, interference is a common drawback with RF technology. Interference occurs when another RF device using the same frequency creates static, which can affect the quality of sound. To minimize interference between radio broadcasts, the transmitter and headphone should be set to a range of channel frequencies. Signal loss results when the wearer strays beyond the transmittal range of the transmitter. In addition, RF headphones use more energy than IF headphones, shortening the life of batteries needed to power the amplifier.
Infrared cordless headphones receive an information signal emitted as an infrared light beam from the base station. For the headphone to work effectively, the wearer must remain within visual range of the transmitter. Thirty feet is the typical maximum transmittal range of most infrared systems.
For most wearers of IR headphones, the limitation in mobility is offset by the improved audio quality because the technology is not subject to radio wave interference. The technology also uses less energy than RF devices, making it more economical, as well.
