If you try to keep in tune with previous notes, you will often start wandering away from the original key. This video has a good example: https://www.youtube.c

If you try to keep in tune with previous notes, you will often start wandering away from the original key. This video has a good example: https://www.youtube.com/watch?v=TYhPAbsIqA8 https://www.youtube.com/watch?v=TYhPAbsIqA8 So in a choral context, you would typically aim to be in tune with the people singing simultaneously. The root note of each chord is pitched according to equal temperament. This has its downsides as well. Consider the chord progression Em -> A7: both chords contain the note G, which in the first chord acts as a minor third, and in the second chord as a minor seventh. The minor third should be pitched 16% of a semitone (cents) above equal temperament, and if we're doing really just intonation and pitching minor sevenths as harmonic minor sevenths, the minor seventh should be pitched 31 cents below equal temperament. So consider a voicing where one voice should hold a G across both chords: this means that even though it's singing the "same" note, the voice should drop 47 cents when the chord changes - almost a full quarter tone! This video from the excellent Voces8 ensemble has an example of how this might sound, at 55:50 (between the first two notes): https://www.youtube.com/watch?v=dDXbQ-2_sns https://www.youtube.com/watch?v=dDXbQ-2_sns I highly recommend watching the whole thing, it goes into a lot of detail about the practical implications of singing in just intonation. For the problem described above, one solution is to avoid the issue by tuning minor sevenths using equal temperament in tricky cases like this one.