Feel the sound in Virtual Reality?

What is “physical audio” in the context of auditory feedback? How does this add to the personal experience of VR?
Reading this article I think they are referring more to how they can convert physical cues into haptic (feeling) feedback. Interesting concept and I would be interested to see it’s interaction with audio and the overlay of audio description especially for people with vision impairment: Redefining Immersive Virtual Experiences With Embodied Audio