As the name suggests, this type of headphones do not have a cable connected to your stereo, cell phone, tablet or computer. They work wirelessly, the sound will be transmitted via a wireless connection protocol such as Bluetooth, radio frequency or infrared.
There are three main types of wireless headphones, which can be divided into two categories: those that require a separate transmitter, and those that do not.
Infrared is rarely used, but there are companies such as Sennheiser that still use it for some of their models. Infrared wireless is the best option for connecting to the TV, but it requires an unobstructed line of sight between the headphones and the transmitter, which means there are limits to both the distance and the angle at which they can be used.
Radio frequency is more powerful. Wireless headphones using radio frequencies can work at distances of up to 45 meters, and the signal can pass through walls, so they can be used for a stereo or a TV. In this case interference is a problem: it increases with distance, and with other wireless devices using the same frequency range (typically 800-900 MHz). It is less secure than Bluetooth. They come with a transmission base that connects to the TV via an optical, RCA or 3.5 mm cable. Perfect for listening to the sound of a TV, as you will not find any lag and its sound is very clear. Its range is really good, reaching up to 100 meters.
The Bluetooth connection works with a radio band that operates around 2.45 GHz, but does not remain constant and can change as needed and to avoid interference. It can use a spectrum of 79 different frequencies (channels) centered on 2.45 GHz. You may have problems of “lag or latency” in the sound in case you do not have the latest bluetooth version available. Its range is much smaller, about 10 meters.
It is a technology designed to operate in a small range, about 10 meters. Bluetooth devices are managed through a “master and slave” relationship. One device controls the other.
Bluetooth technology is your choice if you want headphones without a transmitter, and is the best choice for general use. They require that the device (smartphone, tablet) also has this technology. Bluetooth has a range of about 10 meters.