Wireless speakers basically operate in the same way that traditional speakers work, but with the addition of a transmitter instead of wires that carry signals from the output source to the speakers. There are two main types of transmission media when it comes to wireless speakers: infrared signal-based and RF signal-based systems. Each of them have their own limitations and benefits.
RF, or radio-frequency-based systems broadcast signals to a remote receiver the same way an FM radio does. Such systems are ideal for speakers that will not have a direct line of sight from the transmitter to the receiver. This means the speakers can be placed outdoors or in alternate rooms. However, some barriers such as electronic devices, metal and some plastics may absorb or interrupt RF signals.
Infrared, or IR-based, systems utilize light transmissions to transmit data to the remote receiver. Such systems can only be used in a small area where the speaker receivers and transmitters are less that 20 feet apart. If there is any barrier between the receivers and the transmitter, the transmitted data will not be received. In wireless speaker setups, the transmitter has to be connected to the source output if one is not built in. Wireless speakers are battery powered and can be freely moved around.