The newer 7.1 standard raises this number to 8 by adding two additional side speakers.
The first approach is building so-called virtual speakers by applying signal-processing to the sound and introducing phase shifts and special cues to those audio parts that would typically be broadcast by the remote speakers. The sound is next broadcast by the front loudspeakers together with the front speaker sound components. The signal processing is modeled after the human hearing. Virtual surround eliminates the remote speakers and simplifies the installation and also eliminates long speaker cable runs. The shape of each human’s ear is a little dissimilar. If the form of the ear changes, sound will travel in a different way. Consequently virtual surround will not function equally well for everybody. Another option for simplifying home theater installations and eliminating long speaker cord runs is to employ wireless surround sound kits or wireless rear speakers kits. A wireless solution will normally incorporate a transmitter module that connects to the TV or source and wireless amplifiers that will be connected to the remote loudspeakers. This offers freedom to connect to any type of source. FM transmission is susceptible to noise and audio degradation. A number of products utilize the less crowded 5.8 GHz frequency band and therefore have less competition from other wireless devices.
A third technology employs side-reflecting loudspeakers. There are additional speakers located at the front which broadcast the audio for the remote loudspeakers from the front at an angle. The sound is then reflected by walls and seems to be originating from besides or behind the viewer.