Piano part generator

SPRIG

Draw a line. SPRIG plays a piano part that follows it.

SPRIG composes a piano part over a chord progression and plays it in time with your DAW: an arpeggio whose top note sings the melody, left-hand chords and a bass. Draw a line and the melody follows it. Same settings, same performance. Drag the loop, or everything SPRIG played, onto a track as MIDI or WAV.

PriceLaunch price $35 (until November 7, 2026 (JST), then $49)

Buy SPRIG

Also in Frond 4 Bundle: $99 for 4 tools

Also in Frond 9 Bundle: $149 for 9 tools

SystemsmacOS 12+ (Apple silicon, Intel) · Windows 10 / 11 (64-bit): VST3 and standalone app (SPRIG MIDI: Mac only)
One purchase covers both Mac and Windows.FormatsAudio Unit · VST3 · standalone app
SPRIG MIDI: AU MIDI FXStatusOn sale

Refund policy

Screen and sound from SPRIG 1.0.0.

In this demo

What it does

The parts that make SPRIG different, in plain words.

125 progressions on the circle of fifths

Each progression is drawn as its own figure on the circle of fifths. Click one to play it, or type your own chart. Three styles: Jazz, Neo Soul and Lo-Fi.

1.0.4: Chord names by bar

Chord names appear above each 4-beat bar of the melody panel. Changes within a bar show their beat numbers. Click the chord header to read the full chart.

Reharm in six steps

From none to a chord on every beat: colour tones, secondary dominants, related ii-Vs and tritone substitutes.

16 arpeggio patterns, shaped by your line

From calm (rising, Alberti, open spread) to virtuoso (grand sweep, cascade, broken tenths), a short hook repeated and answered, or runs between the melody notes. Draw across the band at the bottom and the melody follows your line.

Sounds, presets and MIDI

22 built-in sounds, or load an Audio Unit or VST3 instrument into SPRIG, or send MIDI only. 48 presets. Frond SPRIG MIDI is a MIDI effect for Logic Pro that plays the instrument on its track.

How it works

You bring
A chord progression and a line you draw
It does
An arpeggio whose top note is the melody, with left hand and bass
You get
Played in time with your DAW, or dragged out as MIDI or WAV

Screens

Click a screen to see it full size.

SPRIG 1.0.4: chord names for each bar above the melody line.

Details

Price: Launch price $35 (until November 7, 2026 (JST), then $49)
Release date: October 14, 2026
Systems: macOS 12+ (Apple silicon, Intel) · Windows 10 / 11 (64-bit): VST3 and standalone app (SPRIG MIDI: Mac only)
One purchase covers both Mac and Windows.
Formats: Audio Unit · VST3 · standalone app
SPRIG MIDI: AU MIDI FX
Manual: Read the manual
Status: On sale