Are there any resources to understand human hearing?

Wikipedia is a good place to start - and follow the “references”, “Further reading” and “External links”.

able to understand words in ultrasound.

Thus carefully avoiding the words “subliminal recording and messaging.”

Human hearing goes up to about 20,000Hz in pitch and that’s only if you’re a young girl. Everybody else’s hearing stops short of that, sometimes way short if you’re an old man who used to like rock concerts.

Digital services generally stop way short of that, too. Even WAV (Microsoft) 16-bit, Audio CD file format isn’t unconditionally perfect past about 17,000Hz. It fudges everything past that, so you can’t put words or messages up there. They get mangled.

MP3 is even worse. Its job is to delete subliminal sounds. That’s part of what gives it the small files.

There are other problems. It’s an uphill battle.


Including “Rorschach audio” & “auditory verbal hallucination”.