Surround Sound Reproduction

In home theaters, a surround-sound system has the ability and the need to create impressions of Space and Distance as well as the perception of direction.

A typical surround sound system (5.1- channel arrangement) is able to create at least five different locations. Additional locations can be created by making use of a phantom image which can be positioned between two or more channels.

The impressions of distance is a result of delayed sounds as well as reflections from both the recording and the influence of the room. The impression of spaciousness and envelopment was introduced.

A surround-sound arrangement can create different sounds at both ears which leads to the perceived apparent source width (ASW, see 2.4.1), spaciousness and envelopment which are important for the listener in a home theater to perceive the feeling of being in a different space.

The different sounds occurring at both ears can be measured as the interaural cross-correlation coefficient IACC, introduced in 2.4.4 and correlates with the spatial descriptors.

surround sound arrangement

Figure 1: Improving the impression of distance and envelopment by the use of surround sound channels and room reflections.

Figure 1. illustrates a surround sound arrangement with surround loudspeakers reproducing delayed sounds of the front loudspeakers to yield the impression of distance and envelopment.

The thick dashed lines show the direct sound from the front sound stage where most of the sound in movies comes from, while the impression of envelopment will be caused by the surround sound channels.

The figure also shows the additional reflections from the opposite room surface beneficially contributing to the perceived spaciousness. The front and rear wall contributions are ineffective in improving spaciousness and can be avoided by applying absorption on front and rear wall.

In this post, we explained Surround Sound Reproduction; Other types of these methods that need to be mentioned to improve the sound will be published in future posts. These will pave the way for creating a home theater of the highest quality.

Although, we explored two types of sound absorbers that are effective in controlling sound reflections; Other types of these absorbers and the things that need to be mentioned to improve the sound will be published in future posts. These will pave the way for creating a home theater of the highest quality.

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