Journal article
New Evidence That Nonlinear Source-Filter Coupling Affects Harmonic Intensity and fo Stability During Instances of Harmonics Crossing Formants
Journal of voice, Vol.31(2), pp.149-156
03/01/2017
DOI: 10.1016/j.jvoice.2016.04.010
PMCID: PMC5292312
PMID: 27501922
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.
Details
- Title: Subtitle
- New Evidence That Nonlinear Source-Filter Coupling Affects Harmonic Intensity and fo Stability During Instances of Harmonics Crossing Formants
- Creators
- Lynn Maxfield - University of UtahAnil Palaparthi - University of UtahIngo Titze - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of voice, Vol.31(2), pp.149-156
- DOI
- 10.1016/j.jvoice.2016.04.010
- PMID
- 27501922
- PMCID
- PMC5292312
- NLM abbreviation
- J Voice
- ISSN
- 0892-1997
- eISSN
- 1873-4588
- Publisher
- Elsevier Inc
- Number of pages
- 8
- Language
- English
- Date published
- 03/01/2017
- Academic Unit
- School of Music; Communication Sciences and Disorders
- Record Identifier
- 9984719567602771
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