TV: Insignia NS-55L260A13 Rev A Soundbar: Sony HT-CT390
HDMI cable from TV socket labelled "HDMI 1 (ARC)" to soundbar's HDMI ARC socket. Roku in HDMI 2 of TV. Instructions for soundbar say to switch input on the TV to the ARC socket (ie 1), then turn the soundbar on. However, no sound.
TV has no SPDIF socket and the manual's only mention of ARC is that use of it is recommended. No menu option to enable/disable it, though I did cycle through the sound type options (PCM etc) to no avail.
The soundbar works through SPDIF and Bluetooth on other TVs and devices, but I don't have any other HDMI ARC to test it with. HDMI cables were bought >2012 and tried 3 different ones.
I'm a bit confused by having to switch the TV to HDMI 1, because I then have no picture. If I then switch to HDMI then I get a picture but only TV sound (though I did try disabling the TV speakers to no avail). I don't understand why the TV is supposed to be on a non-picture source, unless there is some kind of handshaking going on over ARC while switched to that. The soundbar is not a pass-through HDMI device, i.e. there is only one HDMI socket.
Ideas of what to check, or some settings to change I've not yet found, or an explanation of how ARC works on one input while watching TV on another would be appreciated.