Type a progression, hear it loop, and keep editing while it plays. Each chord shows its notes and its Roman numeral in the key, so you can see why a progression works as well as hear it.
Writing chords
Chord symbols go in the text field, separated by spaces, commas, or bar lines. The parser reads the spellings people actually use:
| Write | Chord |
|---|---|
C Cmaj CM |
C major |
Am Amin A- |
A minor |
G7 |
G dominant seventh |
Cmaj7 CM7 CΔ7 |
C major seventh |
Bm7b5 Bø7 |
B half-diminished |
Bdim B° Bdim7 |
B diminished, diminished seventh |
Dsus4 Dsus2 |
suspended fourth, second |
C/E |
C major with E in the bass |
A token that is not a chord is marked in red on its card and skipped, so a typo never stops the loop. Clicking a card plays that chord once.
Presets in Roman numerals
Every preset is stored as numerals and spelled out in your key, so the 12-bar blues in A comes out as A7 A7 A7 A7 D7 D7 A7 A7 E7 D7 A7 E7. The list covers the four-chord pop loop (I–V–vi–IV), the doo-wop I–vi–IV–V, the jazz ii–V–I, Pachelbel’s eight-chord ground, the royal road progression common in J-pop, and three minor-key standards, among them the Andalusian cadence i–bVII–bVI–V.
Voicing and rhythm
Chords are played in close position between D3 and G5, with the bass note an octave or two below in the C2 to B2 range. A slash chord’s bass note replaces the root.
With smooth voicing, each chord takes the inversion and octave that moves least from the chord before, then the first chord is voiced again against the last so the loop point moves as little as the rest. This is how a keyboard player would play it, and it is why a progression sounds connected rather than stepped.
Four rhythms are available. Hold sustains each chord for its full length. Pulse strikes it on every beat with the downbeat accented. Arpeggio plays eighth notes up through the chord and the root an octave above. Strum spreads the notes 22 ms apart from the bottom up.
Loops without a seam
With Loop selected, the WAV is exactly the number of repeats long. The release of the last chord, which would otherwise be cut at the end of the file, is already playing at the start, because that is what you would hear as the loop comes round. A sampler or DAW can repeat the file with no gap and no click. Let ring adds three seconds after the last chord instead, for an ending.
Example: a minor-key backing loop
Choose the Andalusian preset, set the key to A, the tempo to 96, Pulse rhythm, and the Strings sound. The progression reads Am G F E. The bass walks down A, G, F, E while smooth voicing keeps the chords above it within a semitone or two of each other. Download four repeats as a loop and add the Online Drum Machine’s boom bap pattern at the same tempo underneath.