Hi @southearn,
A warm welcome here in the Roku Community, and thanks for the inquiry!
We appreciate you for bringing this information with us, and we'd be happy to assist. Kindly be informed that Roku TVs are only compatible with Roku wireless speakers and Soundbars. But, you can connect your non-Roku soundbar if it does have compatibility to connect to an HDMI cable that can be located at the back of your Roku TV.
In addition, does the audio/picture sync issue you've experienced happen to a particular channel? Please tell us more about this so we can help you with this further.
All the best,
Kash
Takashi O.
Roku Community Moderator