Harmony basics: chords, cadences and tension

Harmony is what happens when notes sound together, and in most classical music it works as a kind of support system for melody. Chords tell the listener where the music is standing, whether it is settled, restless or on its way somewhere. Following harmony is one of the most rewarding listening skills and one of the least dependent on training.

The terms involved are few, and the feelings they describe are familiar to anyone who has ever heard a piece end and noticed whether the ending felt finished.

Chords

A chord is a group of notes sounded together. The most common type in the tradition is built from three notes in a fixed pattern, producing a stable sound, and a related type that produces a less stable one. Stability and instability are the raw materials: music alternates between the two.

Chords are not evaluated in isolation. The same chord can sound peaceful in one context and unsettled in another, depending on where the music has just been and where it seems to be going.

Cadences: how a phrase closes

A cadence is a harmonic formula that ends a phrase. Some cadences sound final, others sound like a comma rather than a full stop. Composers use the difference to control the shape of a passage, deciding whether each phrase stops or continues.

This is why you can often sense that a phrase has ended before any melodic pause confirms it. The harmony has closed, and the ear registers it.

Tension and release

• A stable chord feels like a resting point.
• A less stable chord creates a need to move onward.
• Delaying the expected resolution makes the tension last longer.
• Resolving the tension produces the sense of arrival.
• Resolving to an unexpected chord produces surprise instead.

Almost all expressive effect in tonal harmony reduces to this alternation of expectation and fulfilment, delayed or withheld.

Harmony at a glance

Why harmony is hard to hear at first

Melody is a single line and easy to follow. Harmony is a background layer, and beginners often hear only the melody plus a vague accompaniment. The skill improves quickly once you know what to listen for: the moment the music seems to relax or tighten, and the moment it finally comes to rest.

A useful habit is to listen to the lowest note rather than the tune. Bass lines move slowly and carry the harmonic weight, so following them reveals the structure with far less effort.

Beyond the basic chords

As the tradition developed, composers added notes to chords and used increasingly distant harmonies. The basic mechanism did not change; the distance between tension and resolution grew, and with it the expressive range. Even music that sounds unfamiliar at first is usually working with the same alternation of rest and movement.

Harmony and memory

Harmonic listening depends on memory. The sense that a chord needs to move comes from having heard where such chords usually go in the music you already know. That is why the skill improves quickly with exposure and why unfamiliar styles can sound formless at first.

The practical consequence is encouraging rather than intimidating. Every piece heard adds to the store of expectations, and the store is what makes a new piece intelligible rather than merely strange.

Where to go next

Listen to the final thirty seconds of three pieces and judge how complete each ending feels. That judgement is harmonic listening, and it requires nothing but attention.