AVR250
E-25
English
Surround modes
Introduction
Your AVR250 processor provides all the key decoding and processing modes for analogue and digital
signals.
Modes for Digital sources
Digital recordings are usually encoded to include information about their format type. The AVR250
detects automatically the relevant format in a digital signal, such as Dolby Digital or DTS, and switches
in the appropriate decoding.
Modes For Analogue sources
Analogue recordings do not contain information about their encoding formats, so the desired decoding
mode – such as Dolby Pro Logic – needs to be selected manually.
Mode Memory
The AVR250 has a comprehensive memory that allows it to store different settings for each source
button. The text below applies to all inputs except ‘DVD-A’.
Dolby Digital or DTS audio data (sometimes collectively referred to as ‘bitstream’ sources) can be output
in three mix modes, selected using the MODE button:
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Surround (e.g., ve main channels plus a subwoofer for a 5.1 source)
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Stereo Downmix
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Mono Downmix
The AVR250 will remember which mix mode was last used with a bitstream source. See ‘Multi-channel
Source Modes’ for more information.
Two-channel audio, regardless of whether it is analogue or digital also can be output in three mix modes,
selected using the MODE button:
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Surround (e.g., Dolby Pro Logic IIx Movie, Neo:6 Music, etc.)
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Stereo (with effects applied for analogue or digital PCM)
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Mono
The AVR250 will remember which mix mode was last used with a two-channel source and, if ‘Surround’,
which particular surround mode. See ‘Two Channel Source Modes’ for more information. If an effect
mode has been applied whilst in Stereo, this will also be remembered.
There is a link between the mix modes for multi-channel bitstream (e.g., 5.1) and two-channel bitstream
(2.0 or 2.1) sources. If a 5.1 source is played in Surround mix mode, the AVR250 will remember this
for all bitstream sources (e.g., DTS-ES Matrix, Dolby Digital 3.0 etc.) and use the maximum number of
speakers the signal is encoded for. As a result, when a 2.0 or 2.1 bitstream is played the Surround mix
mode is recalled and the AVR250 enters Dolby Pro Logic IIx Movie mode to try to recreate the surround
environment from what may be a Pro Logic encoded source. If you would rather listen to a 2.0 or 2.1
bitstream in ordinary stereo (with or without a subwoofer), press MODE to cycle through to the Stereo
mix mode (e.g., Dolby Digital 2/0.0 on the display). However, if the source becomes multi-channel
bitstream (e.g., 5.1) again, the AVR250 will recall Stereo mix mode and therefore output a Stereo
Downmix of the multi-channel signal. Full surround output can be re-achieved by pressing MODE to cycle
through to the surround mode encoded on the disc.
Digital multi-channel sources
Digital multi-channel source material is normally provided as ‘5.1 audio’. The ‘5.1 channels’ comprise of:
left, centre and right front speakers, two surround speakers and a low frequency effects (LFE) channel.
Since the LFE channel is not a full range channel, it is referred to as ‘.1’.
Surround systems decode and reproduce the 5.1 channels directly. Dolby Digital EX and DTS-ES
enhanced decoding systems create one extra rear channel from information buried in the two surround
signals of the 5.1 source. These EX and ES enhanced systems are sometimes referred to as ‘6.1’
systems. This extra surround back channel is normally reproduced through two separate loudspeakers,
creating a ‘7.1 system’.
5.1 Playback on 7.1 speaker systems
When listening to 5.1 channel digital recordings, such as Dolby Digital and DTS on a 7.1 channel speaker
system you will have two speakers producing no sound. These two surround back speakers can be
assigned the same signal as the surround speakers in the ‘Speaker Sizes’ page of the Set-up Menu.
When both the surround and surround back speakers are selected the volume from both will be reduced
by 3 dB to keep the sound levels in balance.
