Stem mastering is the same process as mastering, with the difference that instead of processing a single stereo mix track, we are processing 2 or more tracks of sub-mixes which we call "Stems". For example, instead of exporting the mix as a single stereo track, it can be exported as 2 or more separate tracks (stems), each containing drums, bass, other instruments, and vocals respectively. This gives us greater flexibility and control in mastering, so we can process and correct problems in each stem, affecting the rest of the mix as little as possible