Weeks 1-2 · range · do → sol → mi
Glide between three pitches without letting your voice break.
The rule
pass: correct contour · no gap > 150 ms · 5/5
Three pitches — do, sol, mi — within a fifth. The emerald line is one continuous slide through all three anchor dots; the grey trace shows the same contour with a 280 ms gap where the voice dropped out — roughly twice the allowed break. The exact pitches matter less than the unbroken line connecting them.
Hear it first
A clean siren glide, then the same shape with a register break in the middle — the kind that happens when your chest voice runs out of room and the larynx has to flip. That flip is what we’re training away. The third clip is the same three notes stepped, not glided — also a fail.
What’s happening. A siren is the most direct exercise for the two muscles that change pitch — the cricothyroid stretches the vocal folds to go higher, the thyroarytenoid shortens them to go lower. Sliding smoothly forces those muscles to hand off gradually instead of switching abruptly. Untrained voices break in roughly one in three attempts at this interval; trained ones glide through it without thinking.
Why a fifth — and why this specific contour. A fifth is wide enough to require real laryngeal motion but narrow enough to stay inside one register for most people. We use do → sol → mi specifically because the down-glide from sol to mi is where untrained voices most often crack — putting the difficult transition in the middle of the contour, not at the end, forces you to recover within the same trial. The 150 ms break threshold is roughly the shortest unvoicing a listener perceives as a discontinuity.
Why this is the foundation.Every melodic-contour lesson downstream — five-note hums, scale fragments, intervals, arpeggios, passaggio sirens, melismas — assumes you can change pitch without losing tone. If your voice breaks on a three-note slide, it’s going to break on a real phrase too. Steady this here so the upstream work isn’t fighting the foundation.