Choral Lab
Chorale Harmonizer
$6.99 · Designed for iPad. Not verified for macOS.
Harmonize soprano melodies in four-part Bach chorale style. Browse 410 J.S. Bach chorales with score view, piano roll, and real-time chord analysis.
Choral Lab brings the art of four-part Bach chorale writing to your iPhone. Whether you're a composer, music student, or theory enthusiast, explore one of the most refined harmonic styles in Western music.
Harmonize your melodies. Draw a soprano line on the interactive piano roll and watch Choral Lab instantly generate alto, tenor, and bass voices following authentic Bach voice-leading rules — avoiding parallel fifths and octaves, resolving leading tones, and building natural cadences.
Browse 410 Bach chorales. Explore the complete corpus of J.S. Bach's four-part chorales with full score display, real-time chord analysis, and playback with rich choir sounds.
Two ways to read the music. Switch between a traditional four-part score view with proper notation and clefs, or a piano roll view to see the voice leading clearly laid out across time. Mute individual voices to focus on any single part or study how voices interact.
Generate original chorales. Let the app create complete chorales from scratch in any key — major or minor — with realistic harmonic progressions, passing tones, and Picardy thirds.
Study chord analysis. Follow along with real-time Roman numeral chord labels as the music plays.
Features:
• Interactive soprano piano roll with tie support
• Automatic SATB harmonization in Bach style
• Library of 410 J.S. Bach chorales
• Score view with Bravura music engraving font
• Piano roll view with per-voice muting
• Real-time chord analysis
• Choir, piano, and organ sounds
• MIDI export
Ratings & Reviews
Fixed a crash when exporting MIDI on iPad.
The developer, Martin Adler, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Martin Adler
- Size
- 101.2 MB
- Category
- Music
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
English and 5 more
- English, French, German, Italian, Portuguese, Spanish
- Age Rating
4+
- 4+
- Copyright
- © 2026 Martin Adler
