Neutral third cents and are difficult for most people to distinguish by ear. Neutral thirds are roughly a quarter tone sharp from 12 equal temperament minor thirds and a quarter tone flat from 12-ET major thirds. In just intonation, as well as in tunings such as 31-ET, 41-ET, or 72-ET, which more closely approximate just intonation, the intervals are closer together. Neutral thirds expressed in the form of a ratio of two whole numbers can also be considered as the interval between the harmonics of the same order. For instance, an undecimal neutral third, with a ratio of 11:9, is the interval
Major thirds tuning of major-third and minor-sixth intervals are termed "inverse intervals" in the theory of music. Consequently, chord charts for minor-sixths tunings may be used for left-handed major-thirds tunings; conversely, chord charts for major-thirds tunings may be used for left-handed minor-sixths tunings. Major-thirds tuning facilitates playing chords with closed voicings. In contrast, standard tuning would require more hand-stretching to play closed-voice seventh chords, and so standard tuning uses open voicings for many four-note chords, for example of dominant seventh chords. By definition, a "dominant seventh" is a four-note chord combining a major chord and a minor seventh. For example, the C7 seventh