Screen mirroring via your Roku device doesn't feature any audio, and understandably, this can be a problem for many users.  While you can't use your TV's speakers during Zoom on a Roku device, users can rely on other software – like SmartThings – to separately relay audio to the Roku device.  Users with smartphones can utilize SmartView technology to start screen mirroring and then access SmartThings to select the settings for transmitting audio.  If you're still not getting any sound, check to make sure your devices aren't on mute. This includes checking your Roku, TV, and smartphone. Once both SmartView and SmartThings are connected to your Roku device, check the audio and video with any relevant app on your smartphone.