Here I had naively thought that a live demo would be persuasive....

Here I had naively thought that a live demo would be persuasive. FWIW in my view, Yuval did an excellent demo which included enough technical information to assure any reasonable observer of the properties of the digital speaker. The caveats were clearly pointed out, such as the methodology used to emulate the phone receiver speaker, or the frequency response of the microphone.

If people can watch this and refuse to accept it is a real technology, I don't know what else could convince them. But I think the mere fact this demo was achieved, speaks for itself. It is a triumph for such a small amount of people and financial backers to develop a groundbreaking technology over many years.

I would love to see the technology first hand - and if I can have phone calls with such a clear level of fidelity, it will be life-changing even just for the amount of times I have struggled to hear what people are saying on the phone with background noise and a quiet tinny speaker pressed against my ear...