I am unable to duplicate that issue on my end on multiple browsers and multiple operating systems.
You might have experienced a Vimeo glitch - they are our video hosting provider.
Can you try using a private browser session to check again? If you are able to get sound in the private browsing session then you might want to clear your browser cache.
How to do private session in Chrome: Ctrl + Shift + n.
If you still have problems, go ahead and open up a ticket and we can help you figure out what's going on.