Device-to-device audio communication (think QR codes, but made out of sound) seems very underrated. Much better UX than QR codes or NFC because you don't have to worry about putting your phone in the exactly right place or pointing it in the right direction.

Anyone here with more detailed takes on this?

It would be ideal if you could do it in the high frequency range. 

Then you could play it on loop and have a really nice UX. 

But if I remember right this is lossy and it’s very hard to get the error correction right.

Technowatermelon. Elder Millenial. Building Farcaster. 

nf.td/varun

Nyquist Shannon sampling theorem. As long as high freq is below half the sampling rate, we can losslessly reconstruct the signal.

Long range might be very susceptible to interferences