subject: Latest Technologies Make Installing Multi-channel Audio Products A Breeze [print this page] Multi-channel audio has become mainstream and vendors have developed many types of basic and more advanced technologies including wireless surround speakers, virtual surround sound to simplify the setup of home theater kits. I am going to take a look at several of the latest technologies that were designed to make installing home theater systems a breeze. 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 straightforward, the appearance of multi-channel sound has made installing home theater systems a good deal more difficult by requiring a number of external speakers to create surround sound. In case of 5.1 surround, 6 speakers are used: center, left and right front, left and right rear and a subwoofer. Newer 7.1 systems need a total amount of 8 loudspeakers by adding 2 extra side speakers.
Therefore setting up a home theater has turn out to be pretty hard and long speaker wire runs are normally undesirable for aesthetic reasons. Part suppliers have designed various technologies to simplify the setup.
The first option 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 ordinarily be sent by the remote speakers. The signal processing is engineered according to how the human hearing determines the location of a sound. The sound signal is then broadcast through the front loudspeakers. Because of the signal processing, the viewer is deceived into assuming the audio is coming from virtual remote surround loudspeakers.
This technology minimizes the quantity of needed speakers and eliminates long speaker cables but every person will process sound somewhat differently due to the shape of the ear. Because the signal processing is based on a standard human ear model, virtual surround will not work equally well for every person depending on how much the viewer varies from the standard model.
An alternative approach for eliminating long speaker cord runs is to make use of wireless surround sound devices or wireless speakers. A wireless product includes a transmitter and one or a number of wireless amplifiers. The transmitter connects to the source. The wireless amplifiers connect to the remote speakers. Generally the transmitter component will have amplified loudspeaker inputs and line-level inputs. This offers flexibility to connect to every kind of source. A transmitter volume control helps maximize the dynamic range and avoids clipping of the audio within the transmitter.
Some wireless speaker systems are designed to connect 2 speakers per wireless amplifier. A better solution would come with a wireless amplifier for every remote loudspeaker to avoid the wire runs between each of the 2 remote loudspeakers. Entry-level wireless kits utilize FM broadcast or audio compression which will deteriorate the sound quality to some degree. More sophisticated wireless systems make use of uncompressed digital audio transmission. In multi-channel audio products, it is essential to choose a wireless solution with a latency of only a few milliseconds. This will ensure that the sound of all speakers is in perfect sync. Otherwise there will be a noticeable echo kind result. Many wireless gadgets work in the 900 MHz and 2.4 GHz frequency bands. A number of products use the less crowded 5.8 GHz frequency band and consequently have less competition from other wireless devices.
Another method, which is often referred to as sound bars utilizes side-reflecting loudspeakers. The audio that would ordinarily be broadcast by the remote speakers is instead sent by loudspeakers at the front. These front speakers broadcast the sound at an angle. Then the sound is reflected by the side and rear walls and appears 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 a lot of real-world scenarios with diverse room shapes however.
