On the acoustics of spread lips
Björn E. F. Lindblom, Johan Sundberg, Peter Branderud, Hassan Djamshidpey · 2005
In response to our incomplete understanding of how the 3-D geometry of the lips should be modeled in 2-D area functions, we present some measurements made on simplified physical models of the vocal tract. Our main result is that it is possible to match the formant pattern of a notched tube with that of an unnotched tube provided that an increment is added to the length of the unnotched tube. This increment was found to vary systematically with the depth of the notch and, to some extent, also with the size of the tube’s cross-sectional area. We expect these results to be relevant to representing articulations with the mouth corner posterior to the midsagittal anteriormost point of the vocal tract- as in spread vowels, especially when emphatically and emotionally spoken.