We say that music consists of three things:
- Melody and
Harmony and melody both describe the relationship between pitches (although differently) without respect to their duration, whereas rhythm describes the relationship between sounds and their durations without respect to their pitches. Harmony is what happens when we combine notes in music. If you add one or more notes to another note, and you play them at the same time or in a sequence, then you’ve added harmony to the original note.
This is one way to think about harmony. Harmony is the vertical relationship between pitches. It is a structure, like a lattice; a network. When you understand the relationship between two or more notes harmonically, you are treating them as though they were happening at the same time (even if they are happening one after another). It is possible in this way to think about the way the overall harmonic structure of a piece moves and changes.
Harmony is the thing that most people mean when they talk about theory. Melody is like harmony in that it describes the relationship between pitches, but it is a horizontal rather than vertical understanding. While still a matter of relative structure, the melody is all about the way that notes act in sequence, so that the same 4 notes played in different orders have different melodic values, even if those 4 notes taken together might have the same harmonic structure.
Melody could be considered simply as part of the harmony which focuses on how notes sound together in a sequence. Usually, we add harmony to a melody line (which puts the melody in a certain context and makes it sound richer), or we may add melody to the existing harmony. Rhythm is the relationship, in time, between notes (or sounds in general) regardless of pitch relationships. Rhythm describes the way sounds pulse (or don’t pulse), their speed, and regularity.
Rhythmic structures describe the way a piece moves according to a particular kind of time-based division. While not generally the focus of as much theoretical attention, rhythm is equally as important. An understanding of the role of time and duration in music is essential since music is, after all, a time-based art form. That’s why there is a whole section dedicated to rhythm in this book.
What Makes a Great Melody?
A strong melody is essential to good music. It is the difference between bringing someone’s ear on a ride and driving right past it. A good melody is all about telling a story. It moves and unfolds, builds and releases. It plays against and with the chord structure of a song (the harmony) in a way that makes people want to hear it.
A good melody is hard to understand and even harder to prescribe rules for (read: impossible), but in general, we say that a melody consists of tension and release. That means that a good melody moves away from the harmonic center of the music, building tension, and then moves back in some interesting way, releasing that tension.
To tell a story is to create an arc. To rise and to fall. And that’s what a good melody does: it begins somewhere, and while it usually follows the structure of the chords, it does so in a way that creates movement and drama, that makes a little friction between the single notes in the melody and the structure of the chords (its harmonic structure). In most music, this is followed by some kind of release, in which the relationship between the single notes and the chords is again easy, consonant and stable.