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Description
Distorted vowel production is a hallmark characteristic of dysarthric speech, irrespective of the underlying neurological condition or dysarthria diagnosis. A variety of acoustic metrics have been used to study the nature of vowel production deficits in dysarthria; however, not all demonstrate sensitivity to the exhibited deficits. Less attention has been paid to quantifying the vowel production deficits associated with the specific dysarthrias. Attempts to characterize the relationship between naturally degraded vowel production in dysarthria with overall intelligibility have met with mixed results, leading some to question the nature of this relationship. It has been suggested that aberrant vowel acoustics may be an index of overall severity of the impairment and not an "integral component" of the intelligibility deficit. A limitation of previous work detailing perceptual consequences of disordered vowel acoustics is that overall intelligibility, not vowel identification accuracy, has been the perceptual measure of interest. A series of three experiments were conducted to address the problems outlined herein. The goals of the first experiment were to identify subsets of vowel metrics that reliably distinguish speakers with dysarthria from non-disordered speakers and differentiate the dysarthria subtypes. Vowel metrics that capture vowel centralization and reduced spectral distinctiveness among vowels differentiated dysarthric from non-disordered speakers. Vowel metrics generally failed to differentiate speakers according to their dysarthria diagnosis. The second and third experiments were conducted to evaluate the relationship between degraded vowel acoustics and the resulting percept. In the second experiment, correlation and regression analyses revealed vowel metrics that capture vowel centralization and distinctiveness and movement of the second formant frequency were most predictive of vowel identification accuracy and overall intelligibility. The third experiment was conducted to evaluate the extent to which the nature of the acoustic degradation predicts the resulting percept. Results suggest distinctive vowel tokens are better identified and, likewise, better-identified tokens are more distinctive. Further, an above-chance level agreement between nature of vowel misclassification and misidentification errors was demonstrated for all vowels, suggesting degraded vowel acoustics are not merely an index of severity in dysarthria, but rather are an integral component of the resultant intelligibility disorder.
ContributorsLansford, Kaitlin L (Author) / Liss, Julie M (Thesis advisor) / Dorman, Michael F. (Committee member) / Azuma, Tamiko (Committee member) / Lotto, Andrew J (Committee member) / Arizona State University (Publisher)
Created2012
Description
Traditional consensus in duos with grand piano has been that issues of balance between piano and the other instrument can be corrected through lowering the lid on the piano, particularly when the other instrument has been thought of as less forceful. The perceived result of lowering the lid on the piano is to quiet the piano enough so as not to overwhelm the other instrument, though the physics of the piano and acoustics suggest that it is incorrect to expect this result. Due to the physics of the piano and natural laws such as the conservation of energy, as well as the intricacies of sound propagation, the author hypothesizes that lowering the lid on the piano does not have a significant effect on its sound output for the audience of a musical performance. Experimentation to determine empirically whether the lid has any significant effect on the piano's volume and tone for the audience seating area was undertaken, with equipment to objectively measure volume and tone quality produced by a mechanical set of arms that reproduces an F-major chord with consistent power. The chord was produced with a wooden frame that input consistent energy into the piano, with measurements taken from the audience seating area using a sound pressure level meter and recorded with a Zoom H4N digital recorder for analysis. The results suggested that lowering the lid has a small effect on sound pressure level, but not significant enough to overcome issues of overtone balance or individual pianists’ touch.
ContributorsLee, Paul Allen (Author) / Campbell, Andrew (Thesis advisor) / DeMars, James (Committee member) / FitzPatrick, Carole (Committee member) / Ryan, Russell (Committee member) / Swoboda, Deanna (Committee member) / Arizona State University (Publisher)
Created2017
Description
This document explores and utilizes the Digital Audio Workstations (DAW) Audacity and SPEAR (Sinusoidal Partial Editing Analysis and Resynthesis) to create a visual representation of euphonium timbre consisting of complex harmonic structures. Using one mouthpiece model, the Schilke 51 D, this research explores what effect the mouthpiece material has on the amplification of these harmonic structures. Through four exercises geared at different and specific qualities of euphonium sound, this study aims to find the best mouthpiece material for the ideal euphonium sound.
ContributorsGonzalez, David Thomas (Author) / Swoboda, Deanna (Thesis advisor) / Edwards, Bradley (Committee member) / Navarro, Fernanda (Committee member) / Arizona State University (Publisher)
Created2021