Hear a chord, a scale or a whole chord progression and name what it is. Instant feedback, a running score, and a difficulty you set — from major-versus-minor up to seventh chords, the modes and the progressions most songs are built on.
Recognising chord quality and scale type by ear is what lets you work out a song without sheet music, follow a jam, and hear what a piece is doing while you listen. It is a separate skill from interval recognition and it responds well to short, regular practice.
The third of a chord is what makes it major or minor — a bright, open sound versus a darker, heavier one. Get major versus minor solid before you add anything else. Diminished sounds unstable and wants to move; augmented sounds suspended and dreamlike. Seventh chords add a layer of colour on top of the triad you already know.
Every scale is played from the root, so you are hearing a pattern of steps rather than a single distance. Major and natural minor split at the third. Each mode has a tell — Dorian's raised sixth over a minor third, Mixolydian's flat seventh over a major third, Lydian's raised fourth. Sing along with the scale as it plays and the shape becomes obvious.
The third drill plays a whole progression and asks which one it was. This is the skill that actually lets you work a song out by ear: almost all popular music runs on a handful of movements, and once I – V – vi – IV is unmistakable you have thousands of songs. Do not try to name each chord in turn. Listen for where the tension lands and where it resolves — the V pulling home, the vi darkening the middle, the ♭VII stepping outside the key.
Build the underlying theory with the Music Theory Fundamentals path, drill intervals on the Interval Ear Trainer, and look up any chord or scale in the reference library.