ChordIQ vs music21

ChordIQ teaches sight-reading, ear training, rhythm, singing and music theory through interactive games. It offers more than 30 modes covering reading, chords, scales, theory, ear training, singing and rhythm. Reading practice includes treble, bass, alto and grand staff, key signatures, note values, rests, and Marathon and Survival runs. Ear exercises cover intervals, chords and notes by ear, perfect pitch, solfège scale degrees and melodic dictation. Players can tap written rhythms across ten complexity levels, echo heard rhythms, or sing or play pitches scored with a live cents meter. Supported instruments are piano, guitar, ukulele and bass, with on-screen keyboard or fretboard input in playing modes. External class-compliant MIDI keyboards work on iOS and Android; iOS supports wired or Bluetooth MIDI, while Android uses USB OTG. Scores appear on the World Chart leaderboard, with separate rankings for each mode. ChordIQ runs on Android, iOS and macOS. Its free plan includes most game modes, with ads between rounds. Pro is available as yearly and weekly subscriptions or a one-time lifetime purchase; prices vary by country and appear in the store before purchase.

music21 is a free Python toolkit for computer-aided musicology, used to study music datasets, teach music theory, edit notation, analyze music, generate examples, and compose. It includes a corpus of thousands of encoded works, plus tools for searching that corpus, plotting pitch, and performing advanced analysis such as nPVI. The toolkit works with MIDI and MusicXML and can be extended to handle other formats. Its documentation recommends MuseScore for viewing and editing notation, and describes MusicXML readers including Finale, Sibelius, and Dorico. Optional integrations include LilyPond, Matplotlib, SciPy, PyAudio, and Pygame; music21 can also be used in web-based Jupyter Notebook. It runs on Linux, macOS, and Windows, with web use through Jupyter. The toolkit is BSD-licensed and costs nothing. Some corpus works have separate license restrictions. Users need some familiarity with Python, and music21 works primarily with symbolic music data rather than sound waves; it cannot read notation directly from images or PDFs.