Human beings hear between about 20 hertz and 20,000 cycles per second. But the edges of sound extend beyond that. Dogs can hear up to about 40,000 cycles a second, which is about an octave above us.
And this one, probably about 65, which is a few notes higher than that. There is an upper limit to the frequency that air can support. It’s ridiculously high, something like 5 gigahertz, and it’s related to the size of the air molecules and the speed of sound.
Conversely, there is no lower limit to the frequency air can support. Elephants can hear about an octave below us, down to around 10 hertz. But really, really, really low frequency changes in air pressure?
That’s called weather. What do you suppose that sounds like?
