Julien (Dumky) Couvreur comments on my sonar-discovery thoughts:

"Some problems for measuring distances: -don't you only measure the distances modulo the wavelength?"

Yes...*scratch on back of envelope*... holy cow, those are much shorter than I realized...So much for pure tones; you'd have to use a complex waveform. Which would seem to bring us into the world of Fourier transforms, which goes beyond my "thoughts while dog walking" capabilities....

Why use sound to bootstrap a networked meeting rather than just use IP-level discovery?

The idea was that sound maps perfectly with "people having a conversation" while IP-level discovery is either a figment of the network or WiFi-based....