Thanks for the feedback! We didn't realise this would pose such a problem. We've updated the website so it asks for microphone permission after people press the 'Record' button.
Thank you, that's the perfect solution. Although you probably want to offer people a way to dismiss that modal, too: it's still "waiting" for permission rather than being able to go "wait this is not what I wanted to do how do I get back to the site".
Thanks for letting us know - we've realised we were unclear with our initial correction: the modal that asks for mic permission and explains that all audio processing is done in-browser now only appears when 'Record' is pressed, so users can check out the rest of the website.