5.1 sound plays... Stereo does not
...unless I switch the receiver over to "stereo" (2ch or 7ch).
I had everything set up so that via HDMI in (coming from an Xbox1), with the 661 set to "straight" it all worked just fine. *Something* got switched over, so now when audio plays, it only works if the source is sending 5.1. If it's just an old stereo audio track (eg classic shows on Netflix), all I hear is some murmuring from the sub-woofer.
It's been years since I've had to monkey with settings, so I'm not sure how to trouble-shoot. Does anybody have any tips?