Concept
Wireless speakers are loudspeakers that receive audio signals using radio frequency (RF) waves rather than over audio cables. The two most popular RF frequencies that support audio transmission to wireless loudspeakers include a variation of WiFi IEEE 802.11, while others depend on Bluetooth to transmit audio data to the receiving speaker. Apart from the employed RF standard, such speakers can basically be distinguished by their dedicated field of use. Portable wireless speakers for outdoor use are typically designed for ruggedness, portability and battery life, whereas stationary wireless speakers with a focus on good sound quality are meant to be used in home audio systems or surround sound systems for TV or video. Further, types for special applications like waterproof speakers for use in the shower or speakers for a voice assistant may intermix between the properties of the two former. Wireless speakers are composed of two units: a main speaker unit combining the loudspeaker itself with an RF receiver, and an RF transmitter unit. The transmitter connects to the audio output of any audio devices such as hi-fi equipment, televisions, computers, MP3 players, etc. An RCA plug is normally used to achieve this. The receiver is positioned where the listener wants the sound to be, providing the freedom to move the wireless speakers around without the need of using cables. The receiver/speaker unit generally contains an amplifier to boost the audio signal to the loudspeaker; it is powered either by batteries or by an AC electric outlet. The signal frequency range used by wireless speakers is generally the same as that used by cordless telephones – 900 MHz. The RF signal can traverse walls and floors/ceilings. Most manufacturers claim the signal transmits over a range of 150 to 300 feet (50 to 100 m). Many wireless speakers feature variable transmission channels that can be set using a tuning knob to overcome potential RF interference with other nearby wireless devices, such as cordless phones or baby monitors.
