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ENGLISH
2 Dolby Digital and Dolby Pro Logic
Comparison of home surround
systems
No. recorded channels (elements)
No. playback channels
Playback channels (max.)
Audio processing
High frequency playback limit of
surround channel
Dolby Digital
5.1 ch
5.1 ch
L, R, C, SL, SR, SW
Digital discrete processing
Dolby Digital encoding/decoding
20 kHz
Dolby Pro Logic
2 ch
4 ch
L, R, C, S (SW - recommended)
Analog matrix processing Dolby
Surround
7 kHz
2 Dolby Digital compatible media and playback methods
Marks indicating Dolby Digital compatibility: .
The following are general examples. Also refer to the player’s operating instructions.
Media
LD (VDP)
DVD
Others
(satellite broadcasts, CATV, etc.)
Dolby Digital output jacks
Coaxial Dolby Digital RF output jack
1
Optical or coaxial digital output
(same as for PCM) 2
Optical or coaxial digital output
(same as for PCM)
Playback method (reference page)
Set the input mode to “AUTO”.
(Page 34)
Set the input mode to “AUTO”.
(Page 34)
Set the input mode to “AUTO”.
(Page 34)
1 Please use a commercially available adapter when connecting the Dolby Digital RF output jack of the LD
player to the digital input jack.
Please refer to the instruction manual of the adapter when making connection.
2 Some DVD digital outputs have the function of switching the Dolby Digital signal output method
between “bit stream” and “(convert to) PCM”. When playing in Dolby Digital surround on the AVR-
2805, switch the DVD player’s output mode to “bit stream”. In some cases players are equipped with
both “bit stream + PCM” and “PCM only” digital outputs. In this case connect the “bit stream + PCM”
jacks to the AVR-2805.
Surround
The AVR-2805 is equipped with a digital signal processing circuit that lets you play program sources in the
surround mode to achieve the same sense of presence as in a movie theater.
Dolby Surround
(1) Dolby Digital
Dolby Digital is the multi-channel digital signal format developed by Dolby Laboratories.
Dolby Digital consists of up to “5.1” channels - front left, front right, center, surround left, surround right,
and an additional channel exclusively reserved for additional deep bass sound effects (the Low Frequency
Effects – LFE – channel, also called the “.1” channel, containing bass frequencies of up to 120 Hz).
Unlike the analog Dolby Pro Logic format, Dolby Digital’s main channels can all contain full range sound
information, from the lowest bass, up to the highest frequencies – 22 kHz. The signals within each channel
are distinct from the others, allowing pinpoint sound imaging, and Dolby Digital offers tremendous dynamic
range from the most powerful sound effects to the quietest, softest sounds, free from noise and distortion.
(2) Dolby Pro Logic IIx
• Dolby Pro Logic IIx furthers the matrix decoding technology of Dolby Pro Logic II to decode audio signals
recorded on two channels into up to 7.1 playback channels, including the surround back channel. Dolby
Pro Logic IIx also allows 5.1-channel sources to be played in up to 7.1 channels.
The mode can be selected according to the source. The Music mode is best suited for playing music, the
Cinema mode for playing movies, and the Game mode for playing games. The Game mode can only be
used with 2-channel audio sources.
(3) Dolby Pro Logic II
• Dolby Pro Logic II is a new multi-channel playback format developed by Dolby Laboratories using
feedback logic steering technology and offering improvements over conventional Dolby Pro Logic circuits.
• Dolby Pro Logic II can be used to decode not only sources recorded in Dolby Surround ( ) but also
regular stereo sources into five channels (front left, front right, center, surround left and surround right) to
achieve surround sound.
• Whereas with conventional Dolby Pro Logic the surround channel playback frequency band was limited,
Dolby Pro Logic II offers a wider band range (20 Hz to 20 kHz or greater). In addition, the surround
channels were monaural (the surround left and right channels were the same) with previous Dolby Pro
Logic, but Dolby Pro Logic II they are played as stereo signals.
• Various parameters can be set according to the type of source and the contents, so it is possible to
achieve optimum decoding (see page 41).
Sources recorded in Dolby Surround
These are sources in which three or more channels of surround have been recorded as two channels of
signals using Dolby Surround encoding technology.
Dolby Surround is used for the sound tracks of movies recorded on DVDs, LDs and Video cassettes to
be played on stereo VCRs, as well as for the stereo broadcast signals of FM radio, TV, satellite broadcasts
and cable TV.
Decoding these signals with Dolby Pro Logic II makes it possible to achieve multi-channel surround
playback. The signals can also be played on ordinary stereo equipment, in which case they provide
normal stereo sound.
There are two types of DVD Dolby surround recording signals.
q 2-channel PCM stereo signals
w 2-channel Dolby Digital signals
When either of these signals is input to the AVR-2805, the surround mode is automatically set to Dolby
Pro Logic II when the “DOLBY/DTS SURROUND” mode is selected.
2 Sources recorded in Dolby Surround are indicated with the logo mark shown below.
Dolby Surround support mark:
Manufactured under license from Dolby Laboratories.
“Dolby”, “Pro Logic” and the double-D symbol are trademarks of Dolby Laboratories.