I’m looking to by a Roku Streambar but my tv doesn’t have an optical connection. Will the sound still travel through the HDMI cable?
When you use any of the apps on the Streambar, there wont be an issue.
If you want sound from your TV/devices connected through the TV, your TV needs to support HDMI-ARC.
As long as it supports ARC and you have ARC/CEC enabled in your TV's settings, you should hear sound from your TV/devices connected to it.