Someone said that theres no opcion to remove the notice of power on/power off, but its in the manual (page 11).
Turn the soundbar on, press and hold the [🔛] and [VOL + ] button on the soundbar to enable or disable voice prompts.
Notice OFF●(Solidly red and white LEDs flash 3 times)
Excelent sound and bass for the money you pay for it, I got it in a deal, paying basically the same as I did a couple years ago for a 2.0 soundbar that sound almost the same as the TV itself (also hisense) but now I can notice the difference