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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.

While in the past setting up a TV has been quite easy, the emergence of multi-channel audio has made setting up home theater systems much more difficult by requiring a number of external speakers to create surround sound. While the traditional 5.1 format requires 6 speakers: a front center, two front side speakers, two rear speaker and a subwoofer, the more recent 7.1 format add two additional side speakers.

Thus setting up a home theater has become quite difficult and long speaker wire runs are often undesirable for aesthetic reasons. Several technologies have emerged to simplify this process.

The first approach is creating so-called virtual speakers by applying signal-processing to the audio and introducing phase shifts and special cues to those audio components that would normally be broadcast by the remote speakers. Since the signal processing is based on how the human hearing detects the origin of sound, the audio components which underwent signal processing can be mixed with the front speaker components and broadcast by the front speakers. The viewer is in effect tricked into believing the audio is originating from a location other than the front speakers.

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.

Wireless surround sound products are another method for simplifying home speaker setups and usually come with a transmitter component that connects to the source as well as wireless amplifiers that will connect to the remote speakers. The transmitter will often have amplified speaker inputs as well as line-level inputs and have a volume control to adjust it to the source audio level.

While some wireless speaker kits come with a wireless amplifier that connects to two speakers, other products offer individual wireless amplifiers for each speaker. The most basic wireless systems use FM transmission. FM transmission is prone to noise and audio distortion. More advanced systems employ digital audio transmission to perfectly preserve the original audio. To make sure that all speakers are in sync in a multi-channel application, make sure that you pick a wireless system which has an audio latency of a few milliseconds at most. A high latency would lead to an echo effect. This effect would degrade the surround effect. Wireless kits often use the 900 MHz or 2.4 GHz frequency band. Some products also use the 5.8 GHz band. These products have less competition from other wireless devices than products using the crowded 900 MHz or 2.4 GHz bands.

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 additional information about audio transmitter products from Amphony’s website.