Muffled music audio on streambar

Having audio trouble with my Roku stream Bar that is about 2 years old. 

Another Roku user posted the identical problem, when watching a TV show such as the Grammys where there is a combination of speaking audio and the musical performances all sounds great with the speaking audio but when they switch to a musical performance the sound is very muted, muffled, almost like the singers microphone is turned off yet we still hear them faintly from the nearby guitarists microphone.

The other Roku user is dgray3825.

my model number 18445131492

Exact symptoms the other day during super bowl the game sounded fine but during halftime I could barely hear usher singing, if I turned up the volume to 30 or more I could hear it a bit better but still didn't sound very good.

There are lots of other Roku users posting similar problems and unfortunately you don't post any follow-up or resolutions you often just mention that you are handling with them directly and not on this forum.

Thanks for any help