Onkyo TX-NR 838 Manual page 46

This listening mode can be selected only if your Blu-ray Disc/DVD player
is digitally connected to the unit or the player's output setting is bitstream.
When playing back 5.1 ch sources from Blu-ray Discs, Dolby Digital is
automatically applied.
Dolby EX/Dolby D EX
This mode expands any 5.1 ch music or movie source for 6.1/7.1 ch playback
that can give an effect of surround back speaker. It is suitable for the Dolby
EX soundtrack containing the matrix-encoded surround back channel. Adding
the surround back effect to 5.1 ch source will improve spatial representation
by creating a moving sound effect of 360-degree surround sound or
overhead sound and giving a realistic experience.
Input source: 5.1 ch
Speaker configuration: 7.1 ch surround back
This listening mode can be selected only if your Blu-ray Disc/DVD player
is digitally connected to the unit or the player's output setting is bitstream.
Dolby Pro Logic IIx/Dolby Pro Logic II
This mode expands any 2 ch source for 7.1-ch playback. It provides a very
natural and seamless surround-sound experience, keeping the sound clear.
In case of 5.1 ch without surround back speaker, the mode becomes
Dolby Pro LogicII instead of Dolby Pro Logic IIx.
– PLIIx Movie/PLII Movie: Use this mode with any 2 ch movie.
– PLIIx Music/PLII Music: Use this mode with any 2 ch music source.
– PLIIx Game/PLII Game: Use this mode with any 2 ch game source.
Input source: STEREO, 5.1 ch (PLIIx Movie and PLIIx Music only)
Speaker configuration: 3.1 ch, 5.1 ch, 7.1 ch, 7.1 ch surround back (PLIIx
Movie and PLIIx Music only)
Dolby TrueHD
This mode is for use with Dolby TrueHD sources. The audio from the input
source is output as-is, without surround sound processing.
Input source: 5.1 ch, 7.1 ch
Speaker configuration: 3.1 ch, 5.1 ch, 7.1 ch
This listening mode can be selected only if your Blu-ray Disc/DVD player
is digitally connected to the unit or the player's output setting is bitstream.
DSD
This mode is for use with DSD sources. The audio from the input source is
output as-is, without surround sound processing.
Input source: 5.1 ch
Speaker configuration: 3.1 ch, 5.1 ch, 7.1 ch