That's pretty damned clever.
In a far less sophisticated way, I was able to achieve audio transmission without any extra hardware except for a ~6 foot aux audio cable. This was back when I was maybe 14 years old and I was already building RF circuits with crystal oscillators and such. Learning that audio is sampled at specific frequencies, I was then lead to wonder if the same principles used to send and receive audio through proximal electromagnetism(since electrical current generate fields). While this is obvious to any adult with basic knowledge of science, it was quite novel for me to discover that my boom box radio, when set to auxiliary mode, could slightly pick up audio passing through an open-ended cable from my sound card. What I really didn't expect was that by upping the volume further, I could send a clear signal across several feet. Clearly, this wasn't just the force of magnetism but there was some radio activity happening. I never figured out what was going on, although I hypothesized that the transistors in the microphone input hardware of the boom box were configured in a way that was behaving like a transistor radio.
I would love to understand what was really happening there.