I think it’s cool but with payments you’ll have to address security considerations. How can you prevent someone from spoofing a transaction or spoofing audio for payments?
Seems like an interesting way to start a transaction without needing to buy any specialized equipment.
(If some one knows more, please step in and comment.) I’m guessing some of these could be issues with NFC too but from what I have skimmed online it seems both the tag and receiver would need to be modified to work at larger than normal distances of “1-5cm”[1]. Also much more power is needed to extend the range of NFC than sound since sound strength diminishes with the square of the distance and, from what I have skimmed, magnetic induction used by nearfield NFC diminishes with the cube of the distance [2][3].
1: https://seritag.com/learn/using-nfc/nfc-tag-scan-distance-ex...
2: https://www.physicsforums.com/threads/magnetic-field-strengt...
3: https://physics.stackexchange.com/questions/44037/why-is-nea...