The term “voice leading” refers to the way individual voices move within a melodic line. Different harmonies result from changing notes, and a composer must decide where each voice belongs in the melody and harmony. The term “voice leading” encompasses not only singing voices, but also the voices of the various melodic instruments in a piece. It can be used for two or more instruments, though three-note chords are more commonly used in this type of composition than two-note intervals. Voice leading techniques are commonly used in Baroque music to establish melodies and sub-melodies within a harmonic structure.
Chords can be rearranged and modified to fit in music, even though they are usually written with the root at the bottom for study purposes. When working with a set harmonic structure, a composer can use voice leading to figure out how these chords should be represented in the piece. This method can be used by the composer to decide which notes to keep, which to highlight, and which to eliminate.
This method is almost universal in basic music composition classes. Counterpoint is a well-known method for teaching voice leading. The chords of a piece are defined by modal root progression, and voice leading is used to choose how the chord pieces will sound out within a musical composition.
Chords have basic notes that distinguish them, and effective voice leading can help these notes ring out. When using a triad, voicing the parts of a chord that set it apart from other chords like it is an important part of good composition and arrangement. For example, if the chord in the music is a minor triad (major root, minor third, and fifth), the composer should choose to voice the root and minor third to bring out the minor elements of the chord. If a composer only voices the chord’s root and fifth notes in a multi-instrument composition, it’s impossible to tell whether the chord is minor, as intended, or a major fifth or major triad, which use similar notes.
In addition to theoretical guides that assist composers with voice leading, the instruments used in the piece should be considered. When writing music, the composer must think about not only what sounds good, but also what the singers and instrumentalists can play. Each instrument has a set of notes that it is most commonly played with. Notes written outside of an instrument’s normal range can make a piece more difficult to play, requiring the instrumentalist to have a special skill for notes outside of the instrument’s normal range. When a melody falls outside an instrument’s playing range, many composers choose to switch instruments or transpose notes, unless they are trying to achieve the sound of an instrument played outside of its normal range.