University of Twente Student Theses


Signal processing in experimental room acoustics

Binnerts, B. (2011) Signal processing in experimental room acoustics.

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Abstract:This section gives a short summary of the projects of Peutz that I contributed to during my internship. As the title of this report (Signal processing in experimental room acoustics) implies, was the main assignment to optimize and validate three Matlab codes, used for processing measurement data. Short summaries, describing the operation of these programs are given below. Diff_polar_5gr: is a program used for the analysis of reflection measurements in the anechoic chamber. The program processes impulse response measurements into polar figures and organized text files.  Raci(dist): is a code used for processing “non-scale model” room acoustic impulse response measurements. After filtering and averaging is applied, the required acoustic parameters are extracted from the signal.  WINMLS: is a code similar to the Raci code, but in this case applicable to scale model measurements. Also the output format and code structure is different. The internship started with the task to determine the acoustic transparency of a mesh. The architect of the “Staatsoper Unter den Linden” designed this mesh to visually conceal an added volume to the room, serving to increase the reverberation time. With two different experimental setups it has been shown that the transparency of the mesh was not sufficient for this purpose. The second project involved a scale model research of the “Bühnen Köln” opera. Various structural changes were made to the scale model, while studying the changes of the acoustic field by means of impulse response measurements. However, the most time was spent to the optimisation of the WINMLS and Raci code. The time needed to process all the data of a measurement session has been reduced from more than an hour to less than 15 minutes. Extra features have been added to the programs, including conversion of the acoustic parameters to an Excel file. A detailed summary, describing all the major changes to the codes, can be found in the chapter “Matlab codes scale model analysis”. During the last weeks of my internship a large amount of measurements, concerning a scale model research of a new reverberation chamber design, was efficiently processed. KEYWORDS: Experimental room acoustics, signal processing, programming
Item Type:Internship Report (Master)
Peutz, Molenhoek, the Netherlands
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
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