Hi David,

I don't own either of your devices, but since nobody else has commented I can at least answer your question about ARC. Sending ARC from the TV to the 975 would give you at best the same audio as using SPDIF/coax (compressed Dolby Digital, not TrueHD). Some TVs don't handle passing multichannel from an HDMI input source well.

You may have already done this, but there is a setting in System Settings to direct HDMI Audio Output to HDMI2 (instead of Auto).