Nasal cavities function as a branched second passage shaping voice timbre

Evidence

We have not included the modifications due to the nasal passage and cavities. After all, we can hum a tune with our mouths closed. Even with the mouth open, the different timbre of a voice with and without heavy nasal congestion or with the nose pinched closed is more than ample evidence of the effect of a second passage and chambers to the outside. This leads us to the topic of branched tubes, closed or open. — Eric J. Heller, Why You Hear What You Hear- An…, 1728

Categorization

• XREF: Builds on the side-branch Helmholtz resonator discussion referenced directly in the passage; causal mechanism of acoustic branching changing resonance.