Chord Recognition Trainer
Listen to a chord and identify its quality — major, minor, diminished, augmented, the three sevenths, and extended 9/sus chords. Choose a difficulty level, add inversions, pick a sine or organ timbre, and play each chord as a block or arpeggiated. Every chord is built from exact 12-tone equal-temperament intervals above a random root (A4 = 440 Hz).
ℹ This is an uncalibrated ear-training practice aid, not a test or certification of musical ability. The intervals are mathematically exact in 12-TET, but the “feel” words below each answer (bright, dark, tense, dreamy) are conventional, subjective associations. How a chord sounds also depends on your headphones or speakers and your room. Your score, streak and accuracy are personal practice metrics stored only in this browser — nothing is recorded or uploaded. Use a moderate listening volume.
Answer choices
Tip: use good headphones at a moderate level. Try block playback to learn the overall colour of a chord, then switch to arpeggiated to hear each interval in turn. Turn on inversions once the root-position chords feel easy.
How It Works
A chord is just several notes sounded together, and its quality (major, minor, diminished, and so on) is defined entirely by the pattern of intervals between those notes — not by which note you start on. This trainer picks a random root, then stacks a fixed set of semitone offsets on top of it. A major triad is the root plus 4 and 7 semitones; a minor triad lowers the middle note to 3 semitones; a diminished chord stacks two minor thirds (0–3–6); an augmented chord stacks two major thirds (0–4–8). The sevenths add a fourth note (a major 7th at 11, a flat 7th at 10), and the extended 9/sus chords add or swap further tones.
Each note’s pitch is computed in 12-tone equal temperament with A4 = 440 Hz using f = 440 × 2(m−69)/12, where m is the MIDI note number. So the intervals you hear are mathematically exact — there is no tuning ambiguity. In block mode the notes are summed and played at once through a short click-free envelope; in arpeggiated mode they are scheduled one after another on the audio clock and then re-struck together so you hear both the line and the whole chord. The sine timbre is a single pure partial per note, while the additive timbre adds a few quieter harmonics for a fuller, organ-like tone that can make thirds and sevenths easier to pick out.
Turning on inversions can re-voice the chord so its lowest note is no longer the root (root position still turns up sometimes) — the quality is identical, but the bass and spacing change, which is exactly the harder, more realistic case you meet in real music. After each answer you see the actual root and chord name, any inversion, and a short, deliberately subjective description of how that chord tends to feel. Two honest notes: the descriptions are conventions, not facts, and a chord that sounds clear on studio headphones can sound muddy on laptop speakers — so practise on the best gear you have, and treat the score as a personal progress marker rather than a measure of talent.