akousia
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Close-up of piano keys in low light, the black keys casting soft shadows on the white keys.

Chords, scales, rhythm and harmony

Music theory you can hear.

Understand the chords in a song, hear what changes when you move one note, and try a rhythm of your own. Akousia brings music explanations, playable examples and ear training together. Start with a question, or just press play.

Start with the basicsTrain your ears
No account needed. Everything plays in your browser.
C E G · major chord

Three ways in

Where shall we start?

The basics20 lessons from your first note to building chords and reading music. No prior knowledge needed.Learn504 pages on chords, scales, harmony and rhythm, with explanations and listening examples.Practice20 ear training exercises to help you recognize chords, intervals and other musical sounds.

Never done this before

20 music theory lessons for complete beginners

Start with a few notes on the piano. Hear how they form a melody, play your first chords, and try a simple rhythm. Each lesson explains one idea and gives you something to try. You can do it all in your browser, even if you have never played an instrument.

Start with lesson one
Beginner course20 lessons · no account needed
01What a note isStart here02The distance between two notes→03Why some notes clash→04What a chord is→05The four kinds of triad→
15 more, up to reading musicAll lessons →

Practice

Train your ears on what you have learned

You can know how to build a minor chord and still hesitate when you hear one. These exercises give you practice making that connection. Listen, choose an answer, then replay the example and check the feedback.

Hear intervalsHear two notes and identify the distance between them.Start →Chord qualityListen for the difference between major, minor and seventh chords.Start →Name the progressionHear a chord sequence and identify its pattern.Start →Which scale is that?Listen to a scale and choose its name.Start →

Play it yourself

A piano and a drum kit, right in your browser

Click the keys or play them on your computer keyboard. Hold three piano keys and you see which chord you made.

Hold three keys to hear a chord
Virtual piano88 keys · MIDI · 3 keyboard layoutsThe full keyboard plays the notes as long as you hold them, with a sustain pedal. It works with a MIDI keyboard too.Open the virtual piano →
Tap a pad, or press X for the kick
Virtual drums12 pads · click trackEvery hit sounds the moment you give it. Turn on the click and play along with a beat.Open the virtual drums →
Pianolab 27 chord typesBuild a chord, change the root or inversion, and hear which notes move.Drumlab 12 style groovesPut hits in a grid, then change the tempo and swing to hear the groove shift.

Follow your curiosity

The music theory knowledge base

Look up a chord you have just found, explore why a progression works, or go deeper into songwriting and production. Start with one of these topics and follow your next question.

Chords175 pagesBuild major, minor and extended chords. Hear what changes when you add a note or put a different one in the bass.Explore chords →Scales84 pagesCompare major, minor and other scales. Find their notes and hear how a changed note gives a scale its character.Explore scales →Progressions29 pagesHear familiar chord sequences and follow each change. Learn how to use them as a starting point for your own music.Explore progressions →
Harmony19 pagesExplore how chords work together: create tension, bring a phrase to a close or move into another key.Explore harmony →
KOO'S TIPA minor chord is a major chord with its middle note one key lower.
More topicsIntervalsRhythmMelody and formPlaying and improvisingReading musicSongwritingStylesSound and hearingProduction and arrangingGlossary

Why Akousia exists

Put a sound to the words

I learned plenty of music theory words before I could pick out what they described in a song. I wanted the explanation and the sound closer together.

That is the idea behind Akousia. Read about a chord inversion, then hear the chord with a different note in the bass. Learn what swing means, then change the spacing of the drum hits yourself.

The aim is to help you notice more in the music you love and have more ideas when you play or write. Follow a lesson, look something up, or stay at the piano a while.

About Akousia →
Hear the examplePlay chords, scales and rhythms alongside the explanations.
No account neededOpen a lesson, try an exercise or play an instrument straight away.
Try your own ideaChange a note or a drum hit in the labs and listen to the result.
akousia