Additional Information

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Additional Information

Surround back speakers

Optimum surround sound for different sources

There are currently various types of multi-channel signals (signals or formats with more than two channels).

2Types of multi-channel signals

Dolby Digital, Dolby Pro Logic, DTS, high definition 3-1 signals (Japan MUSE Hi-Vision audio), DVD-Audio, Super Audio CD, MPEG multi-channel audio, etc.

“Source” here does not refer to the type of signal (format) but the recorded content. Sources can be divided into two major categories.

2Types of sources

•Movie audio:

Signals created to be played in movie theaters. In general sound is recorded to be played in movie theaters equipped with multiple surround speakers, regardless of the format (Dolby Digital, DTS, etc.).

Movie theater sound field

 

 

 

Listening room

FL SW C

FR

 

sound field

 

 

 

 

 

SL

SR

FL

SW C

FR

 

 

SL

 

SR

 

 

 

SB

 

SB

Multiple surround speakers

(For 6.1-channel system)

In this case it is important to achieve the same sense of expansion as in a movie theater with the surround channels. To do so, in some cases the number of surround speakers is increased (to four or eight) or speakers with bipolar or dipolar properties are used.

SL : Surround L channel SR : Surround R channel

SB : Surround back channel (1 speaker or 2 speakers)

•Other types of audio:

These signals are designed to recreate a 360° sound field using three to five speakers.

FL

SW

C

FR

SLSR

In this case the speakers should surround the listener from all sides to create a uniform sound field from 360°. Ideally the surround speakers should function as “point” sound sources in the same way as the front speakers.

These two types of sources thus have different properties, and different speaker settings, particularly for the surround speakers, are required in order to achieve the ideal sound.

A 6.1-channel system is a conventional 5.1-channel system to which the “surround back” (SB) channel has been added. This makes it easy to achieve sound positioned directly behind the listener, something that was previously difficult with sources designed for conventional multi surround speakers. In addition, the acoustic image extending between the sides and the rear is narrowed, thus greatly improving the expression of the surround signals for sounds moving from the sides to the back and from the front to the point directly behind the listening position.

Change of positioning and acoustic image

with 5.1-channel systems

 

FL

 

SW

 

C

 

FR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SL ch

SR ch

Movement of acoustic image from SR to SL

Change of positioning and acoustic image

with 6.1-channel systems

 

FL

 

SW

 

C

 

FR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SL ch

SR ch

SB ch

Movement of acoustic image from SR to SB to SL

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