Neutral third 31-tet . Infants experiment with singing, and a few studies of individual infants' singing found that neutral thirds regularly arise in their improvisations. In two separate case studies of the progression and development of these improvisations, neutral thirds were found to arise in infants' songs after major and minor seconds and thirds, but before intervals smaller than a semitone and also before intervals as large as a perfect fourth or larger. The neutral third has been used by a number of modern composers, including Charles Ives, James Tenney, and Gayle Young. The equal-tempered neutral third may be found in the
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