Onkyo TX-NR545 Manual page 87

"Off": Do not use this function
DTS
Make the settings for DTS Neo:6 Music listening mode.
Neo:6 Music
Center Image
Default Value: 2
Adjust the width of the sound field of the front channel when playing in
the DTS Neo:6 Music listening mode.
"0" to "5": Selecting a smaller value brings the sound field of the front
channel to the center while selecting a larger value spreads the sound
field of the front channel to left and right.
Theater­Dimensional
Make the settings for Theater­Dimensional listening mode.
Listening Angle
Default Value: Wide
To enhance the effect of Theater­Dimensional, select the actual angle
of the left and right front speakers as it appears from the listening
position.
"Narrow": Less than 30°
"Wide": Greater than 30°
Position the front speakers 20° to the listening position if you have
selected "Narrow" in "Listening Angle" and 40° if you have selected
"Wide".
Volume
Make the detailed volume setting of the unit.
Maximum Volume
Default Value: Off
Set the maximum value to avoid too high volume. Select a value from
"Off", "30" to "79".
Power On Volume
Default Value: Last