I was recently challenged to fit the entirety of Bohemian Rhapsody into 8Kb of data. I thought it might be impossible, as the original file is 5.7Mb. This would be a compression of 712.5x. However, the challenge said nothing about audio quality, so I still thought it might be possible. To begin, I cut the sample rate to 2k, the lowest any audio format I found supported, changed to opus format, and set compression to 10.
I reduced it to 120kb. That is 475x. The audio was terrible, practically turning Bohemian Rhapsody into death metal. I then decided to try using midi. Using a compressed midi, I reduced Bohemian Rhapsody to exactly 8Kb: 712.5x compression!