Not affiliated at all, but I've just tried LowEnd Forge (GitHub - hannes-wan/lowend-forge-official: Bass-first transcription workbench: isolate low-end audio, edit tab, review waveform and export charts.) and I was blown away with the result. I've wondered how can a bass line be completely isolated from a song, and the other way around, with the bass completely removed from a song, and this program does it. Only one test at the moment but got so excited I had to post about it 
Test was with this song:
Test was with this song: