i have seen articles on similar tech before , and they MAY be true , BUT ! my ( computer ) speakers roll off so bad at higher frequencies that i suspected my hearing , and the cheap dollar store microphones that i employ at home are ahhh , pots frequency range ~ i mean , i do have ultrasonic transceivers that i use with my arduinos , and a tascam that can oversample , but , mmmm , i dunno ?? asking for ultrasound from microphones , chips and system software ( sampling rate and pre-filters and such ) , and speakers of common devices ?? which are ordinarily tasked to common mp3 quality , or about am radio of the '60s ???