What is the circle of fifths?

The circle of fifths is a visual diagram that shows the relationships between the 12 major and minor keys. Each adjacent key is a perfect fifth apart. It helps composers understand key signatures, modulations, and chord progressions. TENSIMUSIC's interactive circle of fifths lets you click any key to instantly see its signature, diatonic chords, and relative minor.

What are music intervals?

A music interval is the distance in pitch between two notes. Intervals are named by their size (unison, second, third, fourth, fifth, sixth, seventh, octave) and quality (perfect, major, minor, augmented, diminished). TENSIMUSIC's Interval Explorer lets you visualize and hear any interval on a staff and piano keyboard.

How do you build a chord?

A chord is built by stacking intervals above a root note. A major triad uses a major third plus a perfect fifth. A minor triad uses a minor third plus a perfect fifth. Seventh chords add another third on top. TENSIMUSIC's Chord Builder lets you construct and hear triads, seventh chords, and extended harmony in any key.

What is the difference between major and minor scales?

A major scale uses the interval pattern: W W H W W W H (whole and half steps), giving it a bright, happy sound. A natural minor scale uses: W H W W H W W, giving it a darker, sadder quality. TENSIMUSIC's Scale Explorer shows you the notes, notation, and piano keys for major, minor, and all seven modal scales in any key.

Is TENSIMUSIC free to use?

Yes, TENSIMUSIC Music Lesson is completely free. All tools — interval explorer, chord builder, scale explorer, circle of fifths, and structured lessons — are available with no account or payment required.

What languages does TENSIMUSIC support?

TENSIMUSIC supports three languages: English, Traditional Chinese (繁中), and Japanese (日本語). You can switch languages using the language buttons in the top navigation bar.

Modern Music Theory

Master Music
Theory & Harmony

Explore intervals, chords, scales and the circle of fifths through interactive tools — built for modern composers and musicians.

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Structured Lessons

Step-by-step lessons with text, notation examples and multilingual explanations.

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Interval Explorer

Visualize and play every interval on the staff and piano keyboard.

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Chord Builder

Construct triads, seventh chords and extended harmony with instant playback.

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Scale Explorer

Major, minor, modes and beyond — hear and see every scale pattern.

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Circle of Fifths

Navigate key relationships and understand harmonic distance at a glance.

Lesson 1

Root Note

Interval

Direction

Root Note

Chord Type

Voicing

Root Note

Scale Type

Master Music Theory & Harmony

Structured Lessons

Interval Explorer

Chord Builder

Scale Explorer

Circle of Fifths

Interval Explorer

Chord Builder

Scale Explorer

Circle of Fifths

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Master Music
Theory & Harmony