SetClass vs Chords Weaver

Explore the building blocks of modern harmony. This app lets you see, hear and manipulate pitch class sets, the foundation of post-tonal and atonal music theory. EXPLORE • Tap notes on the pitch wheel to build any chord or scale. • See the Forte number, prime form, normal form and interval vector. • Check transpositional and inversional symmetry. • Open the K/Kh complex of any set to see which set classes include it or its complement. FIND • Tap notes on a keyboard, or type a Forte number (3-11, 6-Z44) or pitch-class numbers (0 4 7). • Browse all 224 Forte set classes, with Z-relations, filtered by size. TRANSFORM • Transpose, invert and multiply (M5, M7) any set. • Morph smoothly from one set to another. CREATE • Generate sets by cardinality, symmetry and density. • Arrange sets into rhythmic sequences using P, T, I, R and RI operations, with every inversion level. • Build a serial matrix from rows of 2 to 12 notes. • See each set as geometry in tonal space, with symmetry axes. • Export to MIDI and MusicXML. LEARN • A built-in theory guide. • Analysis examples from Debussy, Schoenberg, Stravinsky, Berg, Messiaen and more, with links to scores. Built for students, composers and theorists, from first-time learners to advanced analysis.

Chords Weaver is a hands-on chord instrument you play by ear. Pick a note on the keyboard and it filters to the chords that fit. Choose one, and two pads open up: one shapes its voicing (spread, inversion, octave) while the other suggests where to go next, the right side resolving, the left adding tension. Build a progression on the timeline, and a live piano roll shows exactly what will play. Press play and the progression comes alive with arpeggios, block grooves and strums, each chord ringing in time. Turn on Drift and the voicings slowly wander on their own, so the loop keeps evolving. MORE - Rich arpeggios: ascent/descent, ternary grooves (waltz, shuffle, jig 6/8), a lilting 7/4, and sparse syncopated patterns (charleston, tresillo, offbeat, push). - MIDI Out to your synths, DAW or hardware, with a 24 PPQN clock. - Four scenes, copy and paste, and a "roll a matching bridge" helper. - Optional cloud save: sign in and your progressions follow you to every device. The app works fully offline. - Five languages: English, Français, Español, Русский, 日本語. Free to download. Weaving, voicings, playback and saving are all free. A one-time Pro unlock adds MIDI/WAV/text export and live MIDI-out. No ads, no subscriptions. Signing in is only for optional cloud sync.