Melody, Harmony and Song Structure: The Core Tools of Music Composition

Every song, from a 1930s Broadway standard to a current pop single, is built from the same three ingredients: melody, harmony and structure. Melody is the line of single notes a listener hums back; harmony is the set of chords played underneath that line; structure is the arrangement of sections — verse, chorus, bridge and so on — that organizes the whole piece. Berklee College of Music's songwriting curriculum treats these as a "symbiotic relationship," where choices in one element shape the others, according to the course description for Berklee Online's Songwriting Fundamentals program.

Writing a melody

Berklee Online's Songwriting: Melody course teaches a step-by-step approach to building a melodic line over a chord progression, moving from a single chord tone with decorative notes, to two chord tones connected by passing notes, and finally to full arpeggios and scale-based lines, according to the course's published curriculum. The same course also covers shaping a melody's rhythm to fit the stressed syllables of the lyric, building phrases through repetition, sequence and inversion, and techniques for shortening or lengthening a short musical idea, or motif.

The course also covers writing melodies against a single sustained chord using modes such as Mixolydian and Dorian, and against major or minor pentatonic and blues scales, per the Berklee Online curriculum. For melodies written in harmony with a second voice, the course lists parallel, similar, oblique and contrary motion as the basic ways two melodic lines can move relative to each other.

Building harmony: chords and progressions

Harmony is the layer of chords that supports a melody. Berklee Online's Songwriting: Harmony course covers designing harmonic movement, including cadences and modulation, to guide a song's momentum and resolution. It lists several cadence types used to end phrases — full, half, deceptive, plagal and mixed cadences — and three ways to modulate, or change key, within a song: parallel-key modulation, relative modulation, and a third type the course labels surprising-key modulation. Songwriters can also alter a basic chord progression by subtracting, adding or replacing chords, or by adding a pedal part that holds one note under changing chords, according to the course outline.

Certain short chord progressions recur across decades of popular music. A Berklee Online article on common chord progressions lists several examples, cited below with the songs it uses to illustrate them.

The Berklee Online article notes that songwriters typically do not use these progressions unchanged; they vary the melody, lyrics and arrangement built on top of a familiar chord sequence to make the result sound original.

Arranging song structure

Structure is how a song divides into sections. Berklee's Songwriting Fundamentals course lists the verse as the section that carries storytelling and development, the chorus as the section built around the song's main hook and emotional release, and describes contrast between sections as a way to keep a listener engaged across the whole song. A bridge, used for contrast partway through the song, is listed as a common additional section in the course curriculum.

The two main structural templates covered are verse–chorus–bridge form and AABA form, also called 32-bar form, according to Berklee's course outline. A detailed breakdown of AABA form published by the University of Puget Sound's music theory program describes it as three sections, each typically eight measures long: two A sections carrying the main melody, followed by a contrasting B section commonly called the bridge or middle eight. That source traces the form's prominence to Broadway musicals of the 1930s, citing George Gershwin's "Let's Call the Whole Thing Off" and "Someone to Watch Over Me," Cole Porter's "Anything Goes" and Irving Berlin's "Blue Skies" as examples. It states that AABA remained one of the most popular song forms until the 1950s, when rock and roll rose in popularity, though the form continued to appear in major songs into the 1960s, including the Beatles' "Yesterday," "Norwegian Wood" and "Hey Jude." The same source describes AABA as less common today, giving the Cure's "Friday, I'm in Love" (1992) and Norah Jones's "Don't Know Why" (1999) as occasional later examples.

How the elements interact

None of the three elements is written in isolation. Berklee's Songwriting Fundamentals course frames the relationship between melody, harmony and rhythm as central to songwriting, and ties arrangement choices — instrumentation, texture and rhythmic groove — back to reinforcing the mood set by the melody and lyric, according to the course description. In practice, this means a melody's chord-tone choices are shaped by the harmony underneath it, and both are placed inside whichever structural section — verse, chorus or bridge — the songwriter is writing for.

• Melody: a sequence of single notes, often built from chord tones plus connecting non-chord tones such as passing notes.
• Harmony: the chords underneath a melody, organized into progressions and resolved through cadences.
• Structure: the arrangement of sections — verse, chorus, bridge, or the A and B sections of AABA form — that organizes a complete song.
• Motif: a short musical idea that can be repeated, sequenced, inverted, shortened or lengthened to build a full section.