So crazy. I'd seen on HN that chrome was rolling out that feature, but it didn't seem like a big deal at the time. Chrome already blocks things like pop-ups and flash, but it tells me when it does so and offers me a way to load the pop-up / flash content if I want it.
Doesn't work for me in Chrome Beta or Canary I'm afraid, unless I reload the page which is probably not intuitive for many users.
What I've been doing is sending a pop-up to users on audio-critical pages (where audio is the entire point of the site) that says "hi, let's get started, you'll hear audio on this page so please adjust your headphones or speakers" and that seems to give the best result. It's also helpful on a page like yours where the sound is quite loud and I found it a bit loud for my headphones. You must also just provide a button that changes the sound volume which would have the same effect, of telling Chrome that the user has interacted with the page.
This time, chrome just feels broken.