All SACD's are supposed to have a stereo track, but a surround track and a hybrid CD layer are both optional and may not be present on all discs. This is because it was originally a stereo only format, until pressure from DVD-Audio caused them to start offering surround support. In addition to checking whether the SACD has a surround track or not, I'd also check to see if the Denon has a setting for SACD audio priority. I haven't used Denon's players so don't know how they set them up, but OPPO's players have a setting that determines whether the player loads surround SACD, stereo SACD, or hybrid CD on SACD's that offer all of those. If it's set to stereo SACD, it will play that track even if a surround track is included. Setting it to surround SACD instead will cause it to use the surround track when available and stereo only when there's no surround track.