What To Expect From Multi-Channel Audio System?

Posted on by Donny Billinton on November 2nd, 2011 | 0 Comments »

Multi-channel audio has become mainstreams and vendors have developed many types of basic and more sophisticated technologies like Wireless Surround Sound Speakers, Virtual Surround Sound to simplify the setup of home theater systems. I will look at the latest trends to see which devices actually work. I will also give some guidance for picking the perfect components.

As in the past setting up a TV has been relatively straightforward, the appearance of multi-channel audio has made setting up home theater systems much more challenging by requiring a number of external speakers to create surround sound. While the traditional 5.1 channel needs 6 speakers: a front center, two front side speakers, two rear speaker and a Subwoofer, the more modern 7.1 channel adds two additional side speakers.

Therefore the setup of home theater systems has become a relatively complicated procedure. A lot of homes are not pre-wired for surround sound. In addition, long speaker cables are often unattractive. Some technologies have appeared to simplify this process.

Multi-Channel Audio System

The first solution is generating so-called virtual speakers by applying signal-processing to the audio and introducing phase shifts and special cues to those audio components that would typically be sent by the remote speakers. The sound is next broadcast by the front speakers along with the front speaker sound components. The signal processing is modeled after the human hearing. It utilizes the knowledge about how the human ear can determine the origin of sound. The signal processing has an effect that will deceive the listener into presuming that the audio is originating from a different location.

The advantage of this technology is that only a handful of speakers are required and no longer speaker cable has to be run all through the viewing environment. The downside though is that each person will process sound in a different way as a result of the different shape of every human ear. Because the signal processing is based on a standard human ear model, virtual surround will not function equally well for everybody dependant upon how much the viewer varies from the standard model.

Wireless surround sound products are an additional solution for simplifying home speaker setups and normally have a transmitter module that connects to the source as well as wireless amplifiers that will connect to the remote loudspeakers. This transmitter will generally have line-level and also amplified loudspeaker inputs. Ideally it should have a volume control to adjust it to the audio source.

A few wireless speaker kits have wireless amplifiers that connect to two loudspeakers. This still requires wire runs between the two loudspeakers. Other products come with individual wireless amplifiers for each loudspeaker. The most basic wireless systems utilize FM broadcast. FM broadcast is prone to noise and sound degradation. More sophisticated devices make use of digital audio transmission to perfectly maintain the original audio. Make certain that you pick a wireless system with a low audio latency, at most a few milliseconds. This will guarantee that the audio from all loudspeakers, including the non-wireless speakers, is in sync. Low latency is also vital for good sync with the video. A high latency would lead to an echo effect. This effect would degrade the surround effect. Many wireless products work in the 900 MHz and 2.4 GHz frequency bands. Some products use the less crowded 5.8 GHz frequency band and consequently have less competition from other wireless devices.

An alternative method, which is often called Soundbars like Yamaha YSP-4000BL Digital Sound Projector uses side-reflecting loudspeakers. There are additional speakers positioned at the front which broadcast the audio for the remote speakers from the front at an angle. The audio is then reflected by walls and appears to be coming from besides or behind the viewer. This approach works best in a square room with minimum interior design and obstacles. It will not function well in a lot of real-world scenarios with different room shapes though.

Read my other articles about Understanding A Stereo And Multi Channel Surround Sound System Receiver and Basic Components Of Home Theater System You Better Know

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