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Time Domain Fast-Multipole Translation for Ambisonics

Authors Baumgartner, R.
Year 2011
Thesis Type Diploma thesis
Topic Spatial Audio
Keywords Ambisonics, audio reproduction, signal processing, acoustics
Abstract Representation and reproduction of sound fields is a dedicated goal in electro acoustics and acoustics. There arise more and more possibilities to make sound sources and their emitted acoustic fields audible in a realistic way especially due to modern sound reproduction methods like Ambisonics and Wave Field Synthesis. One important aspect of this field of research is the auralization of directional sound sources. If such a source moves and rotates in space, the resulting tonal changes can be described as proper translation terms. In Ambisonics these operations are expressed as filter matrices. The aim of this work is the implementation and stabilization of these filter matrices in the time domain with regard to real time applications. The implementation of these translation filters could pave the way to further applications for broad band acoustic sound field simulations. Thus the displacement of sound sources is stated in this thesis as a matrix, composed by nearly stable and time discrete IIR-filters, which are determined analytically directly out of the theoretical basics. The emerging filters are designed for playback of multi channel directivity data of sound sources with a multi channel Ambisonics surround loudspeaker setup. Additionally, strategies for translation of incident acoustic fields in combination with possibilities for stabilization of the developed filters are a part of this work.
Supervisors Zotter, F.