Audureau (2021) has argued persuasively that the planetary interpretation of vowel sequences in the Papyri Graecae Magicae (PGM) is largely a modern historiographic construction, and that the primary function of vowels in the Greco-Egyptian ritual corpus is pneumatic: they embody the creative power of breath (πνεῦμα). This paper extends that philological finding into vocal acoustics. Formant analysis of the canonical Greek seven-vowel sequence Α–Ε–Η–Ι–Ο–Υ–Ω, grounded in acoustic phonetic data for Modern Greek vowels (Sfakianaki 2002) and French reference vowels (Georgeton et al. 2012), and in original exploratory spectrographic measurements by the author (a trained overtone singer), reveals: (1) a complete, smooth sweep through the resonant geometry of the human vocal tract, with both F1 and F2 moving continuously; (2) a progressive widening of the F2–F1 spectral gap from Α to Ι (“the formant arc”), followed by a collapse at Ο–Υ; (3) an acoustic rationale for the archaic pronunciation Υ = /u/ over Classical /y/ in ritual performance contexts; and (4) convergence of documented PGM permutation patterns (PGM XIII, 556–559; PGM CXXX; the expanding pyramid) toward smooth, continuous formant trajectories. Keywords: Greek vowels, formant trajectory, Papyri Graecae Magicae, vocal tract acoustics, pneumatic theology, spectral perception, overtone singing, vocal toning, archaeoacoustics, ancient Greek phonology
Ioannis Psallidakos (Thu,) studied this question.