Pop harmony is harmony written for popular music.
Pop is used in its widest sense throughout the guide to include pop music and all its related genres from folk, blues, rock, country and western, punk, hip hop, to whatever is the latest fashion. It covers any type of music written for widespread and popular appeal.
Pop harmony is not counterpoint. It has no rules for writing a melody, intervals have equal status and are not classed as consonant or dissonant, and there are no rules for relative motion.
Pop harmony is not functional harmony. There is an apparent affinity between the two: they are both based on tertian harmony; they both use the triad and the dominant seventh chords extensively; they both use major and minor scales; and they are both written in a clear key. The similarity ends there. The two approaches have innumerable technical differences. For example, there are no rules for voice leading in pop harmony and both parallel fifths and parallel octaves are allowed.
The difference between pop harmony and functional harmony is more philosophical than technical. The main idea underpinning functional harmony is that music has a direction. Every note has a function, every chord has a purpose, and the aim of a chord progression is to promote tonality. In pop harmony, a note has multiple functions, a chord has no purpose, it just is, and a chord progression is a succession of pleasing sounds. Pop harmony may be written in a key, and often is, but not with the aim of promoting tonality.
Pop harmony has no musical purpose. Notes have multiple functions. Chords have no purpose. Chord progressions are a succession of pleasing sounds. These may sound like radical, even provocative, statements, but they are not meant to be. At heart, the issue is about the function of music. Functional harmony fulfils a musical function, pop harmony does not.
The guide takes the view that the objective of pop harmony is social. Its main function is to please. It may have, and probably does have, other objectives as well, such as to entertain, to tell a story, to dance to, to shock, and so on and so forth. These are all social, or cultural, functions, not musical functions
Pop harmony does not have a theory to call its own. In many ways pop eschews theory and rules and promotes the idea that anything goes as long as it sounds good. This freedom to do whatever you like is the defining characteristic of writing pop harmony: if it sounds good to you, then it is OK.
There are two broad approaches to writing a pop song. The first concentrates on the lyrics. A pop song is sung, lyrics are what are sung, and the nature of the lyrics determines the way the song is written. This approach is called songwriting. The second approach concentrates on structure. It treats a pop song as a form of music with a specific shape that is suitable for short pieces of music. This structural approach covers instrumental pop as well as the sung pop covered by songwriting
This part of the guide looks at the structural aspects of a pop song and uses the framework to examine the processes for writing pop harmony. The other aspects involved in writing pop music are covered elsewhere in the guide, namely, writing lyrics, writing melody, writing rhythm, writing noise, creating sound effects and organising instruments.
This part of the guide starts with a look at a complete one-minute pop song followed by a detailed breakdown showing how it was written.
The detail starts with writing a verse using a pop chord progression and changing key through pop modulation. A bridge is an optional feature but it is useful for writing instrumental pop harmony and acts as a showcase for new chords including the suspended chord, various types of add chord and the major and minor seventh chords. Writing a chorus features the hook, the catchy singalong bit, and borrowing a chord from another key is one way to write it.