I have a Polk Magnifi mini connected to the ARC HDMI on a Vizio M43-C1 I was using the HDMI cable that shipped with the Polk, but trying to fix this problem I switched to a BlueRigger high speed HDMI cable from Amazon. STB is a Samsung from Spectrum its connected to the high speed 60hz HDMI on TV. Audio setting on TV is TV speakers off. CEC is set to ARC only (recommended selection for sound bar) The issue is the sound bar does not always power on when I turn on the TV and STB and sometimes there is no sound. So sometimes I have to power on the Polk or disconnect and reconnect the HDMI from the sound bar to get the sound going. Its a bedroom TV I just want everything to work when I turn on the STB and TV
Couldn´t find the feature, that the power automatically is getting on while powering on the other devices. Do you use one remote to power all three devices on? Then maybe the remote is not programmed well or out of range for the sound bar
Is your sound bar connected to the internet? To update the firmware you will have to install the Google Home App and wait one night to update itself. Maybe this will fix your issue.
CEC doesn't always work as intended.
Different manufacturers don't cooperate to make the standard universal.
You can get a Logitech Harmony universal remote that will operate the system. The cheapest one will work just fine. Usually about $30us. It programs quite easily with the My Harmony app from their huge online database of IR codes.