system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do piano notes of lower pitch sound 'rougher' and higher pitch notes sound smooth?
gpt
Low notes vibrate slow enough that you can hear the individual back and forth of the strings. 

High notes vibrate so fast that it sounds like one seamless tone. 

If you were to record a high pitch sound and play it back at a slow speed, you'd hear a low pitch tone instead.