My sound is out of sync.

This can happen. I have experienced this the most with hulu but have also experienced it with netflix amazon and youtube. I have attributed it to 3 things...

1. crappy app

2. streaming demand exceeding transmission speed

3. crappy device

Troubleshooting...

1. Id try using the same service and streaming the same content across multiple devices. ie netflix Breaking bad on a Smart TV and a Smart phone and a tablet. Do they all behave the same way?

2. change the content and try again

3. change the app and try again

What do they all have in common?

Try again with a different provider (try at a friends house or use Starbucks wifi for instance)

Hulu on my old TV SUCKED and would commonly go out of sync...My new TV does not have the same issue The difference was a ROKU vs an Android based  Smart TV...the ROKU version of HULU SUCKED. I gave mu ROKU to my daughter...problem solved (for me)

add-on sound system??