(
BWV 269 and
BWV 347) In the
baroque era, a set of rules developed for
voice leading in four-part harmony. In these rules, the bass voice would be assigned the
root of the chord, although it can occasionally be assigned the fifth or the third. If the chord is a
triad, the root is generally doubled by one of the other voices. When two voices are harmonized in
perfect intervals (fourths, fifths and octaves), repeats of the same interval between the two voices (also known as moving in
parallels) are almost always avoided. Another rule concerns
perfect cadences. In such cadences, the
leading tone (the seventh scale
degree) must resolve step-wise to the tonic. That is, the voice that plays the leading tone must resolve up to the tonic, and if the chord is a
dominant seventh chord, the subdominant should resolve to the mediant. Another concern of four-part writing is
tessitura. Since the music is usually written for four-part choirs, each part should be able to be sung by the appropriate section of the choir, thus it should remain in the appropriate pitch range. As well as that, each voice should be easy to sing, meaning that large intervals within the same voice are to be avoided, instead favoring step-wise motion. Voices should also not overlap: the pitch sung by the alto should not be higher than that of the soprano, and so on for the other voices. Voices should also remain suitably close to each other, usually within an octave of each adjacent voice, except for the bass. These rules were generally followed during the common practice period. Nowadays, they are usually taught in music theory classes, but most compositions follow less strict rules, if not outright disregarding them. ==See also==