Three Chord Qualities — Major, Minor, Diminished

What separates the three is the distance of the middle note

There are only three triads, yet many people never manage to tell them apart. The point of this page: the difference is one thing only — how far the middle note sits from the root.

Three qualities, one listen each

One: major triad (0 / 4 / 7 semitones)

Two: minor triad (0 / 3 / 7)

Three: diminished triad (0 / 3 / 6)

The key: only the middle note moves

Across those three, the root (C) and the top note barely change — what moves is the middle:

This is why you can "see" that major and minor triads are the same shape on the keyboard. They genuinely are the same shape — the fingers just land half a key apart.

Diminished is different — its top note drops too (to the flattened seventh). That is why diminished sounds so tight.

An action you can verify yourself

1. Listen only to the first (major) on "decompose"; 2. Then only the second (minor) on "decompose"; 3. Alternate between them quickly — you will feel those two middle notes (E and E♭) starting to swap places in your mind.

That "swapping" sensation *is* the build-up of identification ability. The method is identical to the interval pages here.

What each quality does in music

• Major: settled, open, a beginning or an ending;
• Minor: darker, worried, a downward pull;
• Diminished: highly unstable — its job is to resolve somewhere else.

The key understanding: a diminished triad is not a "colour". It is a "question". It almost always appears on the beat before going home (dominant to tonic, leading tone to tonic).

So when you hear a diminished triad, the right reaction is not "what colour is this" but "where is it going".

An honest boundary

This page covers triads only. Sevenths, suspensions and added notes all build on the triad — once you have the idea of "the middle note moves", the rest is addition.

Next

• What adding one note produces: seventh chords
• Does changing position change the sound?: inversions
• The second before it resolves: suspensions
• The three qualities in combination: the three commonest progressions

Sources

• 本页为三和弦性质对比练习的说明；和弦构成依据通用乐理记法
• 实例均标注来源与许可档位，可在线试听；练习用的合成音由浏览器实时生成，非录音

Used for fact-checking only; all prose is original.