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Latest Technologies Make Building Multi-Channel Audio Kits A Snap
The process of installing multi-channel audio speakers in home theater products is fairly tedious and vendors have invented new products and technologies including wireless surround sound speakers or surround sound wireless headphones lately to help simplify the installation. I will have a look at a few of the products and technologies which have emerged and give some pointers about choosing proper components for a hassle-free setup.
Most of today’s TVs will be installed as a multi-channel audio system. As traditionally TVs would have built-in stereo loudspeakers, today a number of external loudspeakers are used to let the viewer experience surround sound. While the traditional 5.1 format needs 6 speakers: a front center, two front side speakers, two rear speaker and a subwoofer, the more modern 7.1 format adds two additional side speakers.
Consequently, home theater setups have turn out to be relatively difficult. Running cables to remote loudspeakers also is often undesirable because of aesthetic reasons. Part suppliers have designed several technologies to simplify the installation.
The first option is called virtual surround sound. This approach will take the audio components which would typically be sent by the remote loudspeakers. It then uses signal processing to those components and inserts special cues and phase delays. Next these components are mixed with the front speaker sound. Because 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 sent by the front loudspeakers. Because of the signal processing, the viewer is tricked into believing the audio is coming from virtual remote surround loudspeakers.
The advantage of this technology is that only a small number of loudspeakers are needed and no long speaker cord has to be run throughout the viewing environment. The downside though is that each person will process audio differently because of the different form of every human ear. The signal processing is based on measurements which are done using a standard human ear model. If the form of the ear changes, sound will travel differently. Consequently virtual surround will not function equally well for everyone.
Wireless surround sound products are an additional solution for simplifying home speaker setups and normally have a transmitter component which connects to the source and wireless amplifiers that will connect to the remote speakers. The transmitter will normally come with amplified speaker inputs and line-level inputs and come with a volume control to adjust it to the source audio level.
Some wireless speaker products are designed to connect 2 loudspeakers per wireless amplifier. A superior option would provide a wireless amplifier for every remote speaker to eliminate the wire runs between each of the 2 remote loudspeakers. The most sophisticated wireless systems employ digital transmission to avoid signal degradation. Make sure that you pick a wireless system with a low audio latency, at most a few milliseconds. This will make sure that the audio from all loudspeakers, including the non-wireless speakers, is in sync. Low latency is also important for good sync with the video. A high latency would lead to an echo effect. This effect would degrade the surround effect. Wireless kits frequently utilize the 900 MHz or 2.4 GHz frequency band. A few products also use the 5.8 GHz band. These products have less competition from other wireless devices than devices utilizing the crowded 900 MHz or 2.4 GHz bands.
A third technology uses side-reflecting loudspeakers. This solution is called sound bars. There are extra loudspeakers positioned at the front which broadcast the audio for the remote speakers from the front at an angle. The sound is then reflected by walls and appears to be coming from besides or behind the viewer. This method works best in a square room with minimum interior design and obstacles. It will not work well in many real-world scenarios with diverse room shapes however.