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New evidence that nonlinear source-filter coupling affects harmonic intensity and fo stability during instances of harmonics crossing formants
- Publication Year :
- 2016
-
Abstract
- The traditional source-filter theory of voice production describes a linear relationship between the source (glottal flow pulse) and the filter (vocal tract). Such a linear relationship does not allow for nor explain how changes in the filter may impact the stability and regularity of the source. The objective of this experiment was to examine what effect unpredictable changes to vocal tract dimensions could have on fo stability and individual harmonic intensities in situations in which low frequency harmonics cross formants in a fundamental frequency glide. To determine these effects, eight human subjects (five male, three female) were recorded producing fo glides while their vocal tracts were artificially lengthened by a section of vinyl tubing inserted into the mouth. It was hypothesized that if the source and filter operated as a purely linear system, harmonic intensities would increase and decrease at nearly the same rates as they passed through a formant bandwidth, resulting in a relatively symmetric peak on an intensity-time contour. Additionally, fo stability should not be predictably perturbed by formant/harmonic crossings in a linear system. Acoustic analysis of these recordings, however, revealed that harmonic intensity peaks were asymmetric in 76% of cases, and that 85% of fo instabilities aligned with a crossing of one of the first four harmonics with the first three formants. These results provide further evidence that nonlinear dynamics in the source-filter relationship can impact fo stability as well as harmonic intensities as harmonics cross through formant bandwidths.
- Subjects :
- Adult
Male
Glottis
Sound Spectrography
Voice Quality
Acoustics
Vocal Cords
01 natural sciences
Models, Biological
Article
Speech Acoustics
03 medical and health sciences
Speech and Hearing
Young Adult
0302 clinical medicine
Phonation
Speech Production Measurement
0103 physical sciences
Humans
030223 otorhinolaryngology
010301 acoustics
Physics
Linear system
Filter (signal processing)
Fundamental frequency
Middle Aged
LPN and LVN
Nonlinear system
Formant
Otorhinolaryngology
Nonlinear Dynamics
Harmonics
Harmonic
Female
Vocal tract
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....279f03645f7f5c0bca531001774407ec