There was a post sometime ago that got onto the topic of lowest note that could be played on an instrument. I believe I came up with a super-sub-contra-bass saxophone playing something in the area of 5Hz. Regardless, it was mentioned that the lowest note the human ear can hear is 20Hz. And that is a good healthy ear, many people don't have healthy ears.
We should probably correct this misconception. The statement is accurate and true in laboratory clinical tests. But in the outside world it is different. If you go on to study musical acoustics you will no doubt come across studies done by Physisit Arthur Benade, PhD. Mr. Benade did a lot of work with scientists and musical instrument manufacturers.
In the real world a very low pitched note will give off higher harmonics. So, even if you don't hear the fundamental pitch, in the abscence of the fundamental your nervous system will hear some of the harmonics and some missing harmonics and imply and then generate the correct pitch.
The original statement above in the clinical laboratory will filter out the harmonics so only the base fundamental is generated. But, again, in the real world the upper harmonics are there and we can hear notes lower than our "tested" hearing because of these harmonics.
I thought some of you would find this interesting.