Harmony, where two or more notes sound together, lies at the heart of tonal music. In this lesson, study the structure of chords, combinations of three or more notes heard at the same time, focusing on triads, a group of fundamental three-note chords. Learn about major and minor triads, and the lesser-used diminished and augmented triads, and observe harmony in action in a Bach chorale.

Seventh chords are another essential component of Western tonal music. Observe how seventh chords (four-note chords) are built on triads (three-note chords), by adding another interval of a third. Learn how seventh chords "resolve" or propel the music forward. Study the five types of seventh chords, how they are used in different musical genres, and hear seventh chords in context.

This episode discusses the phrase structure of tonal music. Discover how music unfolds in phrases, segments of musical material that end with a sense of rest or pause, often using a harmonic event called a cadence, which concludes the phrase. Hear how musical phrases operate, and how they are organized into larger units called periods and sentences, which create a musical narrative.

Building on your study of harmony, observe how harmonic motion works, where one chord or tonality leads to another, forming a progression that we hear as a coherent harmonic sequence or event. Study the example of the tonic harmony, the "home" tonality of a piece, as it leads to the predominant harmony, the dominant harmony, and resolves back to the tonic, completing the progression.

In listening to music, we sometimes hear the meter differently than the way it's written on the page. Learn how the concept of hypermeter helps explain this, by showing that when measures of music are grouped into phrases, we often hear a pulse for each measure in the phrase, rather than the pulses within the measure. Explore examples of hypermeter, and how we perceive music as listeners.