World 4 · Chords & Harmony · 7 min · PRONinths & extensions
Beyond the seventh
PRO · Sound & Music Lab
World 4: Chords & Harmony is part of PRO
The first world of Sound & Music Lab is free. PRO opens the other 52 lessons in 6 worlds — simulations, quizzes and all.
PRO includes
- All 26 labs — every world, every lesson
- Practice exams and certificates
$8.33/mo, billed yearly ($99.99) · or $39.99 monthly