Articulatory Activity Of The Tongue, Jaw, And Lips During The Second Passaggio Acoustic Transition Of Female Singers

Sopranos typically exhibit an acoustic modification between 600 and 700 Hz (on /ɑ/) during which second resonance (R₂) tracking of the second harmonic (2f_o) changes to first resonance (R₁) tracking of the fundamental (f_o).

To quantify the alteration, the sound pressure level difference between the first two harmonics (L₁-L₂) was measured for chromatic scales sung between C5♮ and G5♮ (523 to 784 Hz) by 17 sopranos (9 judged by the first author as “techniqued” and 8 as “untechniqued” and confirmed by perceptual experiment).

Techniqued sopranos shifted from negative to positive values of L₁-L₂ as early as D5♮ (587 Hz), while the least techniqued singers did not make the change at all.

Articulatory correlates were measured using ultrasound of the tongue and optical tracking.

Head-corrected tongue contours showed the most critical articulatory factor to be the size of a triangular area between two points on the hard palate and the most anterior tongue point.

Sopranos who made the change earliest exhibited the largest anterior oral cavities whereas sopranos who never made the acoustic change had significantly smaller anterior cavities.

Larger anterior oral cavities appear to accommodate lower frequencies of R₂, presumably lowering L₂ and increasing L₁-L₂. [Supported by NIH grant DC-002717.]