Voice leading refers to the series of “paths” that voices in a chord take to move to voices in another chord.
Efficient voice leading refers to the series of paths connecting two chords that result in the minimum cumulative intervallic distance between voices. Efficient voice leading is characterized by a “smoothness” that results from handling of voices as perceptually independent entities. Much of the time, the practice of voice leading implies using methods that result in efficient voice leading.
Let’s use a few simple examples:
Triad to Triad
Seventh Chord to Triad
Counterpoint is the relationship between two or more voices that share a harmonic context yet are independent in rhythm and melodic contour.
Types of Contrapuntal Motion
The relationship 2 notes maintain in a harmonic context can be described by their contrapuntal motion: parallel, contrary, oblique, or similar
Parallel – both voices move in the same direction by the same interval
Contrary – both voices move in the opposite direction of each other
Oblique – one voice remains common, the other voice moves
Similar – both voices move in the same direction, but by different interval distances
Motion to Avoid When Voice Leading
The following types of motion are typically avoided when voice leading to maximize the perceptual independence of each voice.
Consecutive Octaves occur when two voices of a chord voicing form the interval of a perfect octave between each other AND move to form a perfect octave between each other in the new chord.
Consecutive 5ths occur when two voices of a chord voicing form the interval of a perfect fifth between each other AND move to form a perfect 5th between each other in the new chord.
Octave displacement is irrelevant (a perfect 12th is functionally the same as a perfect fifth).
Hidden octaves occur when a perfect octave is formed through similar motion between 2 voices.
Hidden fifths occur when a perfect fifth is formed through similar motion between 2 voices.
Why are consecutive/hidden 5ths and consecutive/hidden octaves undesirable? #
Consecutive 5ths and consecutive octaves are often avoided due to the perceptual phenomenon referred to as tonal fusion, where the two tones are perceived as one due to their close relationship within the harmonic series. In efficient voice leading, the emphasis of voices as independent entities is important, and therefore practices that avoid tonal fusion are recommended.
A Computational Cognitive Model of Voice Leading #
For a deep-dive into the complexity of voice leading, check out this fantastic analysis by Peter M C Harrison and M. Pearce
How to Voice Lead in Cymasphere
