system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Have we heard and written down every musical tone that's possible?
gpt
Yes and no because of the limitations of human hearing. Tonally: The human hearing range only encompasses tones between (approximately) 50Hz-20,000. As we get older, this is shaved down and we lose hearing in some of those frequencies. So because we can only hear tones in that range, we can't truly fathom tones outside of it.

Dogs, on the other hand, have a hearing range from 40Hz-60,000. Therefore, they can hear sounds we cannot. 

Musically: In western culture, we really only recognize 12 notes to make music with. (A-Bb-B-C-Db-D-Eb-E-F-Gb-G-Ab) These repeat themselves through higher and lower octaves. Some other cultures use a different set of notes in between those notes. There are pitches in-between all those notes and we often refer to them as +/- cents sharp or flat.

Intelligent life could recognize sounds far below or above our hearing range and even communicate in sound waves we can't fathom.

Edit: For those of you who wish to claim 20-20,000- this is true- from birth. The average person has hearing loss shaved off both ends of spectrum from life things such as having the car window open, airplanes, concerts, fireworks, trains, etc.