Marantz NR1605 - Manual (Page 119)

Auto surround playback
This mode detects the type of input digital signal, and automatically
selects the corresponding mode for playback.
Perform stereo playback when the input signal is PCM. When the input
signal is Dolby Digital or DTS, the music is played back according to the
respective channel number.
1
Press PURE to select “Auto”.
Auto surround playback begins.
This can also be set by pressing PURE DIRECT on the main unit.
Contents Connections Playback Settings Tips Appendix
119 Front panel Display Rear panel Remote Index