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Physical Sciences and Mathematics Commons

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Theses and Dissertations

2009

Acoustics

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Full-Text Articles in Physical Sciences and Mathematics

Scan-Based Near-Field Acoustical Holography On Partially Correlated Sources, Michael D. Gardner Aug 2009

Scan-Based Near-Field Acoustical Holography On Partially Correlated Sources, Michael D. Gardner

Theses and Dissertations

Scan-based near-field acoustical holography (NAH) is applied to partially correlated sources. Partial field decomposition via the virtual coherence method is used to implement the scan-based NAH. The background and theory of these methods are developed. Multiple stationary reference microphones are required for the partial field decomposition. Guidelines for reference microphone placement in the literature thus far have been limited. Improved guidelines for reference microphones are given after the results of two sets of experiments. The first set involves discrete, partially correlated sources, both physical and numerical. The second set of experiments is strictly numerical and involves continuous sources. Fewer microphones …


Development Of An Adaptive Equalization Algorithm Using Acoustic Energy Density, Panu Tapani Puikkonen Apr 2009

Development Of An Adaptive Equalization Algorithm Using Acoustic Energy Density, Panu Tapani Puikkonen

Theses and Dissertations

Sound pressure equalization of audio signals using digital signal processors has been a subject of ongoing study for many years. The traditional approach is to equalize sound at a point in a listening environment, but because of its specific dependence on the room frequency response between a source and receiver position, this equalization generally causes the spectral response to worsen significantly at other locations in the room. This work presents both a time-invariant and a time-varying implementation of an adaptive acoustic energy density equalization filter for a one-dimensional sound field. Energy density equalization addresses the aforementioned challenge and others that …