Since we can't guess the makes and models the only advice I can give you is to convert whatever audio output the TV has to whatever input the soundbar has. If the Android box has an audio output and it's your only source you can connect it's audio output to the soundbar bypassing the TV completely for audio.
Most soundars have an ARC HDMI input and an optical input, some also have stereo RCA.
If your TV supports ARC you will need to figure out which HDMI input that's for and connect that to the soundbar and then enable it in the TV menu.
If you have a coaxial SPDIF output it can be converted to optical.
For my cheapo Veon TV I had to turn on HDMI (CEC) to then be able to turn on HDMI (ARC)