I've been using the A-780 without issues, or so I thought, since 2018. I was checking my settings today and decided to run a Tone Check. I could hear the tone from all of my speakers but the sub. I had just updated to firmware 2.01 but that usually doesn't change anything. I contacted the Sub mfr (Emotiva) and according to them, the sub settings were correct. If I run a YouTube 5.1 sub test, I can't get any sound out of the sub. So, is there a setting I need to check or change on the A-780 before considering that the sub has died. \n\nThe sub is set to LFE with the x-over set to max (120Hz) as recommended. Phase is Normal.\n\nThe A-780 uses manual speaker settings (the YPAO settings didn't sound right to me). Audio is set to DSP Straight, Power Amp Assign is Basic, Configuration is Small, Bass Boost is Off, Phase is Normal.