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The process of setting up multi-channel audio speakers in home theater systems is fairly tedious and manufacturers have invented new products and technologies such as wireless surround sound speakers or surround sound wireless headphones recently to help simplify the installation. I am going to look at some of the most recent technologies which were developed to make setting up home theater systems a snap. I will point out what to look out for when making your buying decision.

Most of today’s 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. In case of 5.1 surround, 6 speakers are used: center, left and right front, left and right rear and a subwoofer. More recent 7.1 systems require a total number of 8 speakers by adding 2 additional side speakers.

Therefore, home theater installations have become rather complex. Running wires to remote speakers also is often undesirable due to aesthetic reasons. Component vendors have come up with a number of technologies to simplify the installation.

One solution is reducing the number of speakers by creating virtual speakers. This method applies signal processing to the audio and adds phase shifts and cues to the audio that would normally be broadcast through the remote speaker. The signal processing is designed based on how the human hearing determines the location of a sound. The audio signal is then broadcast through the front speakers. The signal processing has an effect that will trick the listener into assuming that the audio is originating from an alternate location.

The advantage of this technology is that only a few speakers are required and no long speaker cable has to be run throughout the viewing environment. The drawback though is that each human will process sound differently due to the different shape of each human ear. The signal processing of these virtual surround systems is based on a standard model which was measured with a standard ear. However, virtual surround will not work equally well for every person.

Another approach for simplifying home theater setups and eliminating long speaker cable runs is to use wireless surround sound systems or wireless speakers. A wireless solution will typically include a transmitter component that connects to the TV or source as well as wireless amplifiers that will be connected to the remote speakers. This transmitter will usually have line-level as well as amplified speaker inputs. Ideally it should have a volume control to adjust it to the audio source.

Some wireless kits come with wireless amplifiers that connect to two speakers. This still require cable run between the two speakers. Other products offer separate wireless amplifiers for each speaker. Entry-level wireless systems use FM transmission or audio compression which will degrade the audio quality to some extent. More advanced wireless kits employ uncompressed digital audio transmission. Make sure that you choose a wireless system with a low audio latency, at most a few milliseconds. This will ensure that the audio from all speakers, including the non-wireless speakers, is in sync. Low latency is also important for good sync with the video. If the latency is more than 10 ms then there will be an echo effect which will degrade the surround sound. Most wireless products operate in the 900 MHz and 2.4 GHz frequency bands. Some products use the less crowded 5.8 GHz frequency band and therefore have less competition from other wireless devices.

Another method, which is often called sound bars uses side-reflecting speakers. The audio that would normally be broadcast by the remote speakers in instead sent by speakers at the front. These front speakers send the audio at an angle. Then the audio is reflected by the side and rear walls and appear to be originating from besides or behind the viewer. The effect largely depends on the shape of the room and interior design and not work well in many real-world scenarios due to different room shapes and obstacles in the room.

You can get further information regarding wireless surround sound products from Amphony’s website.

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