Pitch, Scales, and Key
How musical pitches are named and ordered into scales, modes, and key systems.
Definition
The organization of pitch into ordered collections (scales and modes) and the hierarchical key systems that establish a tonal center.
Scope
Covers the naming of pitches and pitch classes, octave and enharmonic equivalence, the construction of major and minor scales (natural, harmonic, melodic), the diatonic modes, key signatures, and the circle of fifths that relates keys to one another. Stops short of the chordal syntax built on these scales, treated under harmony.
Core questions
- What is the difference between a pitch and a pitch class?
- How are major and the three forms of minor scale constructed?
- What is a key, and how does a key signature encode it?
- How does the circle of fifths organize the relationships among keys?
- What are the diatonic modes and how do they differ from major and minor?
Key concepts
- Pitch class and octave equivalence
- Major scale
- Natural, harmonic, and melodic minor
- Diatonic modes (Ionian, Dorian, etc.)
- Key signature
- Circle of fifths
- Relative and parallel keys
- Enharmonic equivalence
History
Modal organization inherited from medieval church practice gave way during the seventeenth and eighteenth centuries to the bipolar major-minor key system, whose web of relationships the circle of fifths conveniently diagrams.
Key figures
- Guido of Arezzo
- Gioseffo Zarlino
Related topics
Seminal works
- clendinning2021
- aldwell2019
Frequently asked questions
- What is the difference between a scale and a key?
- A scale is an ordered collection of pitches; a key is the tonal system that makes one of those pitches a center of gravity toward which the others resolve.
- Why does minor have three forms?
- Natural minor is the basic diatonic form; harmonic minor raises the seventh degree to create a leading tone, and melodic minor adjusts the sixth and seventh to smooth melodic motion toward the tonic.