Weeks 11-12 · transfer · shape-over-key
Take a phrase you know. Sing it from a different starting note.
The rule
pass: shape preserved + ≥2/3 notes on 3 of 4
Same three-dot contour, two starting pitches. The lower trace is the motif at the source tonic; the upper is the transposed version a P5 above. Both pass only when the intervals between notes are preserved — pitch is anchored relative to the new tonic. The failure mode is key bleed: your voice keeps drifting back toward the source tonic, so each note lands flat of where it should be in the new key.
Hear it first
Motif at the source key, the new tonic alone, and the motif starting from that new tonic. The tonic-only cue between source and target is your only reference — train your ear to grab it.
What’s happening. Transposition tests whether you stored the motif as a contour of intervals (key- independent) or as a list of absolute pitches (key-locked). Untrained singers fail transposition tasks at ~60% even on phrases they can sing perfectly in the original key — the shape never abstracted away from C major. This drill forces that abstraction.
Why a P5 or P4 jump, not a small interval. A whole-step transposition is too forgiving — the source tonic still sounds “in the right neighborhood” and your motor memory can mostly carry over. P4 and P5 are large enough that key-bleed is audible and key-anchoring is forced. They’re also the most musically useful intervals — most real-world transpositions in pop and folk land near these.
Why this is the capstone.Verse- and song-from-memory lessons assume the phrase is internalised as a shape, not a key. Live music — singing along with a guitar in a different key, joining a choir that pitched the song down — depends on it. This is the last barrier between “I can sing this song” and “I can sing this song wherever.”
Session ahead
4 trials · hear motif at source tonic, then the new tonic (P4 or P5 above), then sing the motif from the new tonic · each note ±50¢ for 2.0s · land the new tonic + ≥2/3 notes · 3/4 promotes.