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Development and Evaluation of an Algorithm for the Enhancement of First-Order Ambisonic Impulse Responses

Authors Hoffbauer, E.
Year 2020
Thesis Type Audio Engineering project
Topic Spatial Audio
Keywords Ambisonics, B-format, Higher-Order Ambisonics (HOA), microphone arrays
Abstract For the immersive sonic representation of a room, e.g. with a convolution reverb, it is useful to measure an Ambisonic room impulse response (ARIR) with a microphone array. This is usually performed in First Order Ambisonics (FOA), out of practical and monetary reasons. However from the playback perspective Higher Order Ambisonics (HOA) have many advantages, like a sharper resolved representation of directions and depth, which results all-in-all in a recording subjectively perceived as very natural sounding. As follows a interesting approach for improvement is to develop algorithms that enhance recorded signals of lower order in a realistic way as possible to a set of HOA signals and combine in that way the advantages of both the recording and playback domain. In the first part of this project thesis an algorithm based on the principles of the Spatial Decomposition Method (SDM) is developed, that decodes via the estimation of the pseudo-intensity vector multiple directions of a given first-order and encodes them again in any desired order. In the second part the results of this algorithm are compared to other known algorithms in a listening test and possible advantages and drawbacks are investigated.
Supervisors Frank, M.