Question MI Soundbar refuses to accept input from HDMI to audio splitter

[Prickly]

My XiaoMI soundbar runs perfectly on bluetooth, but then its volume Up controls don't work. Using TV's volume Up has no effect and it sounds on a base level. I tried using HDMI to audio splitter (using SpDif), which runs on 2.1 okayish, but when switched to 5.1, weird sound results, even if the soundbar is muted from TV side. On bluetooth, it runs 5.1 okay.

Any idea what can be wrong? (the soundbar has Aux, Line In, SpDif, Optical and bluetooth). On using Optical, there is considerable sync problems and voice often lags.

 

[hang-the-9]

Likely the issue is with the splitter. For the bluetooth volume control, use the soundbar remote not the TV one.

 

[Prickly]

Tried 2-3 splitters, but, unfortunately behaved the same. The soundbar did not come with a remote.