Chord Types Explained

Major triad

Root — Major 3rd — Perfect 5th  ·  C major = C-E-G

The major triad is the most familiar chord in Western music. It sounds bright, stable, and resolved — the sound of arrival, certainty, and satisfaction. When a pop song lands on its final chord and everything feels complete, that's almost always a major triad.

The major third (four semitones above the root) gives the chord its characteristic brightness. Combined with the perfect fifth (seven semitones), the result is a harmonically balanced, consonant sound. You'll hear major triads everywhere: the opening chord of "Let It Be," the triumphant ending of a film score, the I chord in nearly every pop song ever written. In ear training, major is usually the first quality you learn to recognise — it's the baseline against which everything else is compared.

Minor triad

Root — Minor 3rd — Perfect 5th  ·  C minor = C-Eb-G

Lower the third by one semitone and everything changes. The minor triad sounds darker, more introspective, and often melancholic. It's the sound of reflection, longing, and emotional depth. But "sad" is an oversimplification — minor chords can also sound mysterious, cool, powerful, or beautiful depending on context.

The difference between major and minor is a single semitone in the third, but that small change reshapes the entire character. Adele's "Someone Like You" lives in minor tonality. So does the verse of "Billie Jean." So does most of Chopin's output. Learning to distinguish major from minor instantly is the single most important ear training milestone for harmonic recognition, and it's the first quality distinction ChordFrog introduces — minor chords appear from Level 1 (The Campfire).

Diminished triad

Root — Minor 3rd — Diminished 5th  ·  C diminished = C-Eb-Gb

The diminished triad takes the minor triad's already dark quality and compresses it further by lowering the fifth. The result is tense, unstable, and dissonant — a chord that practically demands resolution. It sounds like a question mark, a cliffhanger, or the moment in a film when something unsettling is about to happen.

Built from two stacked minor thirds (three semitones each), the diminished triad has a symmetrical interval structure that gives it an ambiguous, rootless quality. In classical harmony, it typically appears as a passing chord — the vii° chord in a major key, leading strongly to the tonic. In jazz, diminished chords serve as substitution and tension devices. In film scoring, they're the go-to for suspense. Despite being rare as a standalone chord in pop, the diminished triad is unmistakable once you learn to hear its compressed, anxious character.

Augmented triad

Root — Major 3rd — Augmented 5th  ·  C augmented = C-E-G#

Where diminished compresses, augmented expands. Raising the fifth by a semitone from the major triad creates a wide, floating, dreamlike sound. The augmented triad doesn't sound happy or sad so much as unmoored — it's the musical equivalent of being suspended in mid-air.

Built from two stacked major thirds (four semitones each), the augmented triad is also symmetrical, which gives it a characteristic quality of not wanting to land anywhere specific. The Beatles used augmented chords famously — the transition in "Oh! Darling" and the chromatic movement in "Because." Steely Dan, Radiohead, and film composers all reach for augmented chords when they want to create a sense of otherworldliness or harmonic suspension. In ear training, augmented chords are the trickiest to identify at first because they're heard less frequently, but their unique colour becomes clear with practice.

Sus2

Root — Major 2nd — Perfect 5th  ·  Csus2 = C-D-G

Suspended chords replace the third with either a second or a fourth, removing the major-minor identity entirely. Sus2 substitutes a major second for the third, producing an open, spacious sound. It's neither bright nor dark — it's ambiguous and modern, like a wide-open landscape.

You hear sus2 chords throughout rock, pop, and ambient music. The Police's "Every Breath You Take" uses them prominently. So does much of U2's guitar work. The sound is clean and unresolved, but not tense — it sits comfortably without pushing toward resolution. For ear training, sus2 chords are easier to identify once you learn to hear the absence of the third. Without that defining interval, the chord sounds hollow in a distinctive way. The second sits close to where the third would be but doesn't fill the same harmonic role.

Sus4

Root — Perfect 4th — Perfect 5th  ·  Csus4 = C-F-G

Sus4 replaces the third with a perfect fourth, creating a chord with more tension than sus2. The fourth sits just one semitone above where the major third would be, and your ear can feel it wanting to resolve downward. This gives sus4 chords an anticipatory, leaning quality — like the moment before a door opens.

In hymns and classical music, sus4 chords appear as cadential suspensions that resolve to major. In rock and pop, they're used for their own sake — the Dsus4 to D movement is one of the most recognisable guitar gestures in music. Pete Townshend built entire songs around sus4 voicings. For ear training, the key distinction between sus2 and sus4 is tension: sus4 pushes toward resolution, while sus2 is content to float. Both sound "open" compared to major and minor, but they have different internal tensions.

Inversions

An inversion is the same chord with a different note in the bass. A C major triad in root position has C as the lowest note (C-E-G). In first inversion, E is the lowest note (E-G-C). In second inversion, G is the lowest note (G-C-E). The chord quality doesn't change — it's still C major — but the voicing sounds different because the bass note colours everything above it.

ChordFrog displays inversions in real time in Free Pond mode and validates them in Lily Pad Drill. Recognising inversions is an advanced skill, but ChordFrog surfaces the information so you can start building awareness of how the same chord sounds different depending on which note is in the bass.

Slash chords

Slash chord notation like C/E means "C major chord with E in the bass." This is another way of notating inversions — C/E is first-inversion C major. But slash chords can also indicate non-chord-tone bass notes, like C/Bb, where the bass note isn't part of the triad itself.

ChordFrog uses slash chord notation to display what you play. When you play E-G-C on your keyboard, ChordFrog shows it as C/E — telling you both the chord identity and the bass note. This notation matches what you'd see in a lead sheet or chord chart, so the visual feedback in ChordFrog directly translates to real-world music reading.