Haiku Deck Pro subscribers can now add audio to their presentations using a new feature that exists as part of our Presentation Video function in the web app. Though this feature is not yet part of our iOS app, users can use the Haiku Deck web app after the fact to add audio to presentations originally created via the iOS apps.
You can also access this functionality from within the Haiku Deck web app editor while you're working on a presentation. Look for the microphone control on the left hand side for adding audio narration. Click the film-strip icon at the top to export as a video.
To learn more about how to add audio, watch this short video:
When slides have audio recordings attached to them, viewers will see a play icon on the lower left corner of slides when viewing presentations on HaikuDeck.com. This is shown below: