Sharp Roku tv's use the same IR code set as Vizio Tv's, and some Vizio soundbar respond to Vizio tv commands. In that case you can't change the IR either responds to, but you can stop using IR for your Roku tv and get Wifi Roku voice remote, then it will control the tv volume by wifi.
If the problem is cec, turn off the 1-youch play box in the Roku tv settings:
settings> system> control other devices> uncheck the 1-touch play box.
Edmund
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