Load of horse shit. unfortunately I’m at a party in Palm Springs to give a full explanation but the long and short is that voice is transmitted in waves.
Those waves actually change over different mediums. in order to reach a 90% accuracy you would need to sample an original wave directly from Fisherman.
They are comparing wave signals over cell which are vastly different than those over land lines.
In fact, a land kindling transmission is more accurate to the original wave of the spoken voice than cellular which shorten the wave initially and actually becomes erratic over than various mediums a cell phone travereses .
This guy is ginning garbage for an anterior self serving motive
I wasn’t going to go there, but since you did: most cell phone calls are digitized at some point. Spectrum is also limited. Seriously alters the frequency make up of the voice, although not in ways that are apparent to an untrained ear. Would definitely jack with computerized voice comp software, though.