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Surround back speakers
The THX Surround EX format adds new “Surround Back” (SB) channels to the conventional 5.1-channel system. 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.
FL
C
SW
FR
FL
C
SW
FR
SR ch
SL ch
SL ch
SR ch
SB ch
Change of positioning and acoustic image
with 5.1-channel systems
Speaker(s) for one or two channels are required in order to achieve a THX Surround EX system with the AVC-A1XVA. Adding these, however,
allows you to achieve stronger surround effects not only with sources recorded in THX Surround EX, but also with conventional 2- to 5.1-channel
sources. The WIDE SCREEN mode is a mode for achieving surround sound with up to 7.1 channels using surround back speakers, for sources
recorded in conventional Dolby Surround as well as Dolby Digital 5.1-channel and DTS Surround 5.1-channel sources. Furthermore, all the Denon
original surround modes (see page 151) are compatible with 7.1-channel playback, so you can enjoy 7.1-channel sound with any signal source.
Movement of acoustic image from SR to SL
Change of positioning and acoustic image
with THX Surround EX system
Movement of acoustic image from SR to SB to SL
2
Number of surround back speakers
With THX Surround EX, the surround back channel consists of one channel of playback signals, but we recommend using two speakers. The
modes that use the new ASA technology from THX (See page 189) are most effective when using two monopole type surround back speakers
placed close together.
Using two speakers results in a smoother blend with the sound of the surround channels and better sound positioning of the surround back
channel when listening from a position other than the center.
2
Placement of the surround left and right channels when using surround back speakers
Using surround back speakers greatly improves the positioning of the sound at the rear. Because of this, the surround left and right channels
play an important role in achieving a smooth transition of the acoustic image from the front to the back. As shown on the diagram above, in a
movie theater the surround signals are also produced from diagonally in front of the listeners, creating an acoustic image as if the sound were
floating in space.
To achieve these effects, we recommend placing the speakers for the surround left and right channels slightly more towards the front than
with conventional surround systems. Doing so sometimes increases the surround effect when playing conventional 5.1-channel sources in the
THX Surround EX mode. Check the surround effects of the various modes before selecting the surround mode.
