As historically TVs would come with built-in stereo loudspeakers, these days a number of external loudspeakers are used to allow the viewer experience surround sound. The most commonly used 5.1 surround sound format requires setting up a total of 6 speakers. The newer 7.1 standard raises this number to 8 by adding two extra side speakers.
The first solution is called virtual surround sound. This technique will take the audio components which would normally be broadcast by the remote speakers. As the signal processing is based on how the human hearing detects the origin of audio, the sound components which underwent signal processing can be mixed with the front speaker components and broadcast by the front speakers. Virtual surround avoids the remote loudspeakers and simplifies the setup and also avoids long speaker wire runs. On the other hand, it also has a disadvantage. As a result everybody processes sound differently. This transmitter will generally come with line-level in addition to amplified loudspeaker inputs. This still requires wire runs between the two speakers. The most sophisticated wireless surround systems highlighted at amphony.com employ digital transmission to eliminate signal degradation. Wireless kits frequently utilize the 900 MHz or 2.4 GHz frequency band. It will not work well in a lot of real-world scenarios with diverse room shapes however.