Multi-channel audio has become mainstream and manufacturers have developed many types of basic and more sophisticated technologies like wireless surround sound speakers, virtual surround sound to simplify the installation of home theater kits. I will look at the newest trends to see which devices actually work. I will also give some advice for picking the best components.

The majority of recent TVs will be installed as a multi-channel audio system. While traditionally TVs would have built-in stereo speakers, these days a number of external speakers are used to let the viewer experience surround sound. The most commonly used 5.1 surround sound format requires setting up a total of 6 loudspeakers. These are one center speaker, two front side speakers, two rear speakers and a subwoofer. The more recent 7.1 standard increases this number to 8 by adding two extra side speakers.

For that reason, home theater setups have turn out to be pretty complicated. Running wires to remote loudspeakers also is often undesirable due to aesthetic reasons. Vendors have recently introduced new products and technologies. These products were created to help simplify the installation of home theater kits.

One well-known choice for doing away with wires is the use of a kit. Another approach is creating so-called virtual speakers by applying signal-processing to the sound and introducing phase shifts and special cues to those audio components that would typically be broadcast by the remote loudspeakers. Since the signal processing is based on how the human hearing detects the origin of audio, the audio components which underwent signal processing can be mixed with the front speaker components and broadcast by the front loudspeakers. Due to the signal processing, the viewer is tricked into assuming the audio is coming from virtual remote surround speakers.

Virtual surround avoids the remote loudspeakers and simplifies the setup and also eliminates long speaker cord runs. On the other hand, it also has a drawback. The form of each human’s ear is somewhat different. Therefore everybody processes sound in a different way. Because the signal processing is based on a standard human ear model, virtual surround will not work equally well for everybody depending on how much the viewer varies from the standard model.

A different solution for eliminating long speaker wire runs is to make use of wireless surround sound kits or wireless speakers. A wireless product contains a transmitter and one or a number of wireless amplifiers. The transmitter connects to the source. The wireless amplifiers connect to the remote loudspeakers. Customarily the transmitter part will have amplified loudspeaker inputs and line-level inputs. This provides freedom to connect to each type of source. A transmitter volume control helps take full advantage of the dynamic range and eliminates clipping of the sound inside the transmitter.

Whereas a number of wireless speaker products have a wireless amplifier that connects to two speakers, other devices offer individual wireless amplifiers for every speaker. The most basic wireless systems employ FM transmission. FM broadcast is prone to noise and sound degradation. More advanced systems utilize digital audio transmission to perfectly preserve the original audio. To make certain that all loudspeakers are in sync in a multi-channel application, make certain that you pick a wireless system that has an audio latency of a few milliseconds at most. If the latency is higher than 10 ms then there will be an echo effect which will deteriorate the surround sound. A number of wireless devices work at 5.8 GHz which offers the advantage of less competition from other wireless devices than systems employing the crowded 900 MHz or 2.4 GHz frequency band.

Another method, which is often referred to as sound bars utilizes side-reflecting speakers. In this case the audio for the remote loudspeakers will be broadcast by individual loudspeakers positioned at the front at an angle and reflected by walls as to appear to be originating from besides or behind the viewer. This approach works best in a square room with minimal interior design and obstacles. It will not work well in many real-world scenarios with different room shapes though.