[rafa1981]

Maybe the source was compressed audio instead of flac/wav?

Edit: the source is an mp3, which removes audio frequencies based on perception/masking with other frequencies. It's perfectly normal that it is showing artifacts. A better source is needed.

[mwcampbell]

I encoded the source in MP3 for your convenience. But the source that I fed into Spleeter was FLAC.

Edit: I uploaded the original FLAC to my web server last night, before I decided that MP3 would be more convenient:

https://mwcampbell.us/tmp/spleeter-demo/jonathan-coulton-re-...