Passaggio
The transition zone between vocal registers — the few notes where chest voice gives way to head voice and the voice naturally wants to crack or shift.
Passaggio (Italian for "passage") is the most-discussed handful of notes in vocal pedagogy. It's the bridge between your chest voice (the heavier, speech-like register most of us live in) and your head voice (the lighter, resonant register that sits above). Untrained singers usually hit this transition and either crack, push harder, or strain — none of which sound or feel good.
Most singers have two passaggi. The first (primo passaggio) is where chest voice starts feeling effortful; the second (secondo passaggio) is where head voice fully takes over. The exact pitches depend on voice type — a tenor's secondo passaggio sits around F#4–G4, a soprano's around F5. Knowing where yours land is the first step to navigating them smoothly.
Training the passaggio is what unlocks belting, rock screaming, riff agility, and operatic high notes — basically every vocal style that lives above your speaking voice. The work is technical (lip trills, sirens, modified vowels) and patient (months, not weeks). But a smooth passaggio is the difference between a singer who hits the high note and a singer who flies through it.