Choral alpha

Musician's toolbox — interactive chord & progression explorer for guitar, bass, banjo & piano

Key & Mode

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Circle of fifths — pick a key and mode; everything else follows.

Mode
Click a key on the circle — outer ring major, inner ring minor

Progression generator

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Build progressions from presets or random functional harmony.

Genre progressions

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Signature changes by style — voiced in the current key.

Progression ID

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Type a chord progression — analyzed as roman numerals in the current key.

Diatonic chords

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The seven chords in the current key — click one to inspect it.

Chord Diagram

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Fingering chart for the selected chord on your instrument.

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Any chord:

CAGED C major

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The five open-chord shapes of one major triad, moving up the neck.

root   3rd / 5th

Arpeggio

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Chord tones across the neck — the scale map filtered to the arpeggio.

root   chord tone

Chord Builder

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Enter a voicing by fretboard, keys, or tab to identify the chord.

Tab:

Scale

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Map of the current mode across the fretboard or keyboard.

root   scale degree

Metronome

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Click track with tempo, tap, and time-signature control.

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BPM

Vibe generator

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Roll a mood — get a matching key, mode and tempo, then apply it to retune the whole board.

roll for a vibe ↓

Song structure

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Typical sections, their usual bar counts, and the classic forms they're arranged into.

Sections

Intro4–8
Verse8–16
Pre-chorus4–8
Chorus / refrain8–16
Post-chorus4–8
Bridge / middle 88
Solo / instrumental8–16
Outro4–8

Common forms

Pop / rockI·V·C·V·C·B·C·O
32-bar standardA·A·B·A · 8 each
12-bar bluesI×4 IV×2 I×2 V IV I V
StrophicA·A·A·…
EDM16-bar build–drop
Phrases almost always come in 4/8/16-bar blocks — at 120 BPM in 4/4, 16 bars ≈ 32 s, and most songs run ~80–140 bars (3–4 min).