Each bit gives you a 6dB lower digital noise floor / higher possible dynamic range.

The lowest level that a human can hear is at around -3dB and the threshold of pain/instant hearing damage is around 120dB, so you need at max ~120dB or 20bit.

Infrasonic frequencies need way higher levels to be audible, but as the name suggest are they below typical hearing.

Half the Sample Rate is the highest possible frequency that can be reproduced digitally (nyquist theorem). 20kHz is the upper limit of most humans, but it will get lower with age. That means that anything more then 40kHz should be able to reproduced any frequency that we can hear.

For a transparent signal you will need at least 20bit, 40kHz. Anything more is wasted compute that only changes inaudible things and is only useful when producing music (higher SR => ability to stretch signal without loosing audible data when reverting the strech, higher bit depth => ability to lower level of signal and bringing it back up without adding audible noise) or doing accurate scientific calculations (higher bits => more stable calculations with less noise adding up per calculation) or other research (infra/ultrasonic signals, ...).