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Cough is a motor act of the laryngeal and respiratory systems. Features of coughing have been considered in the examination of respiratory, swallowing and voice disorders. Although some voice disorders have been linked to excessive coughing, the precise relationship between cough and voice remains unknown. The present study examined the acoustic features of cough across sex and age; and its relationship to the perception of voice production. A total of 30 cough samples and 30 voice samples were collected from 15 healthy females and 15 healthy males; ranging from young age (17-25 years old), middle-aged (30-45 years old) and older-age (60 years old & above). Coughs containing three distinct phases were submitted to an acoustic analysis of the long-term average spectrum (LTAS) and cough duration. Both cough and voice samples were examined perceptually by a group of 20 speech-language pathologists. Results found a distinct three-phase pattern of cough that was remarkably stable across sex and age. Significant differences were found in the duration of each phase of cough. Perception of cough was not significantly related to acoustic features of cough. Perceptual judgment of sex was comparable for both cough and voice samples. However, the accuracy of age recognition was higher for voice samples compared to cough samples. In addition, voice was judged to be healthier and stronger than cough. Overall, the results partially support the previous acoustic findings on cough. A strong relationship between the acoustics of cough and the perception of cough was not evident. Listeners judged voice differently from cough, except for sex recognition. The clinical implications of the findings are discussed.

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The ARG (Acoustic Research Group) at the University of Canterbury has a goal to image objects buried under the seafloor. In order to image these objects, accurate models and a good understanding of the acoustic parameters of the seafloor are needed. The relevant acoustic parameters to model the seafloor include: physical classification, speed of sound, acoustic impedance, density, and roughness. Acquiring accurate acoustic parameters for the seafloor is a challenging task that requires different approaches depending on the environment, especially in locations with low visibility. This thesis looks at a non-invasive method of acoustically examining the roughness spectrum and acoustic impedance of the seafloor. To achieve these goals, spherical transducers with a continuous bandwidth between 30 kHz and 130 kHz were chosen to examine the frequency dependent specular and diffused components of the reflection from rough seafloor surfaces. Using spherical transducers allows the surface scattering to be examined independently of the transducer beam-pattern. This thesis examines the range and validity of the tools required to make these measurements and presents empirical results measured in the controlled environment of a cylindrical 3.5m diameter by 2m deep sonar test tank. Using results from the sonar test tank, this thesis demonstrates that the acoustic impedance, speed of sound, and density of the material of the seafloor can be measured from a single seafloor realisation measured at multiple angles, provided the seafloor material has a critical angle. Additionally, this thesis demonstrates that the spectrum of the specular and diffused components of the rough-surface reflection requires averaging multiple seafloor realisations to be statistically relevant. As well as describing the benefits of using spherical transducers, this thesis presents some of the problems and potential solutions for future applications.