system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does "on hold" music on a phone sound like it's under water?
gpt
Most human voice is between 300 Hz and 3000 Hz. So most phone systems are designed for these frequencies. In addition human voice have a lot of familiar patterns so you can save bandwidth by compressing it with special algorithms for voice. However music is usually between 30 Hz and 20,000 Hz and follow very different patterns. So the high and low notes will get cut off and the voice compressor will mangle the rest of the notes. This makes the music very strange to listen to.