What are "Full range speaker"

Yes, we're physically capable of 20 to 20k yet we don't hear the extremes often unless you have your system is hooked up to a frequency generator.
I'm not sure what note you can hear at 20 hz but I only felt the "wind".

Happy listening

I can't think of anything that generates a 20Hz note. However, there are plenty of natural phenomena that generate sounds incorporating 20Hz frequency in part. For that matter, much lower frequencies too.

I can't think of anything that generates a 20Hz note

A church organ, for one. Chips... (OK, that's an electronic device).
One problem with actually "hearing" a 20Hz note is its length -- ~17,5 m. So, when it's there (rarely) we perceive reflected sound.
It's also very difficult to reproduce, requiring tons of amplification power and excursion from the driver(s)