Pretty cool, I've never heard of this phenomena, to where if you use a balloon, you could preserve some auditory functionality even as you go deaf.
Also interesting to see how well he's able to speak for someone who went deaf as a child. Most deaf people I assumed would have far more trouble with attempting something like that level of articulated speech, but since he once knew what sound was, perhaps that much stayed with him.
There was one odd thing though that got me feeling like
and that was 3:10
"But he is so focused as he listens that he can tell which cable has been swapped in a stereo system by listening alone far more reliably than most audiophiles".
Seems Stereophile were baselessly making this claim. As right after that claim was made, the man says:
"You know, there's a lot of guesswork involved in listening to a balloon because there is a lot of detail that I am unable to hear and so I'm trying to figure it out in my mind"
I don't think the guy is remotely considering the idea that he can tell when cables are swapped, so I'm not sure why they made the claim that he can.