Hi,
I was playing with the settings of my external audio and activated the HDMI control option (it has CEC RHID, but no ARC), with that I can control the volume of my TV from the external sound system, and I can mute the external speaker from the TV remote control. Great. But, now both speakers (internal TV and external system) are both on all the time (with a noticeable delay). I tried turning off the TV speaker in Menu -> Speakers and selecting "External audio system", but that keeps the TV speakers on. If I choose the "TV speakers" option in the same menu, the external speaker is muted as expected. With either option, if I press mute (or lower the volume) both the TV and the external speaker gets muted.
I have an HDMI connection from the TV (JVC Android TV) to the external sound system (Onkyo TX-SR507) and a SPDIF cable for 5.1 sound from the TV to the sound system (no ARC on the sound system). Also, the TV is 4K but the sound system is only FullHD, so I need to keep this setup to have 5.1 sound (through SPDIF) and 4K video.
Any suggestion other than turning off HDMI control? Thank you!
Here's a guess: it's passing the audio out (from the TV to the sound system) via HDMI and then the sound system is passing it back in to the TV via SPDIF.
Disconnect SPDIF. HDMI can carry extremely high quality audio if you have a new enough cable.