July 2018 - Akustik-kolloquium - lists.rwth-aachen.de

20.07.2018: Akustisches Kolloquium am ITA
by Ingo Witew 16 Jul '18

16 Jul '18

Sehr geehrte Abonnenten des Kolloquium-Newsletters, am Freitag, 20.07.2018 ist einer der nächsten Termine für das Akustische Kolloquium am Institut für Technische Akustik der RWTH Aachen. *Termin* *Vortragende* *Titel* 20.07.2018, 10:30 Henry Hasti /UROP-Student////// / <http://www.akustik.rwth-aachen.de/cms/Technische-Akustik/Das-Institut/Aktue…> How much does the sound field in auditoria change from one position to the next? <http://www.akustik.rwth-aachen.de/cms/Technische-Akustik/Das-Institut/Aktue…> 20.07.2018 11:00 Matthias Reffgen /MSc-Student/ Untersuchungen zur Kopfhörerwiedergabe mittels individueller und nicht-individueller HRTFs <http://www.akustik.rwth-aachen.de/cms/Technische-Akustik/Das-Institut/Aktue…> Die Vorträge werden im Seminarraum des Instituts (Kopernikusstraße 5) gehalten. Zusammenfassung: *How much does the sound field in auditoria change from one position to the next?* by Henry Hasti Despite being a noble planning goal, designing an auditorium with equally good listening positions throughout entire audience areas is a target difficult to achieve. In practice, the acoustic conditions within an auditorium usually span a wide range of values. Knowing which range is "normal" will help acousticians to learn how accurately they need to design concert halls. Also it will help to understand how accurate acoustical measurements in rooms need to be. This question can be answered when sound fields in auditoria have been measured in detail and the changes from one position to the other can be analysed. A robot has been built that is capable of doing such measurements autonomously. In this project the acoustics of a concert hall and an orchestra rehearsal room were surveyed using the robotic array device. The data was analyzed to look at how acoustic parameters vary throughout performance spaces under different conditions. *Untersuchungen zur Kopfhörerwiedergabe mittels individueller und nicht-individueller HRTFs* von Matthias Reffgen Aktuell ist der Einsatz der binauralen Geräuschsynthese im Bereich der Erzeugung von auditiven virtuellen Welten in vielfältigen Anwendungskontexten von besonderem Interesse. Dabei fokussieren diverse Studien auf die präzise Bestimmung von individuellen kopfbezogenen Übertragungsfunktionen (HRTF), die Ermittlung von anthropometrischen Daten sowie deren Einflüsse im Zeit- und Frequenzbereich. Alternativ nähern verschiedene Verfahren basierend auf vereinfachten geometrischen Modellen spezifische individuelle kopfbezogene Übertragungsfunktionen an, um den messtechnischen Aufwand zur Bestimmung individueller HRTFs zu reduzieren. Dies erscheint für eine kommerzielle Verbreitung der Binauraltechnik elementar. Zur Beurteilung der Performanz verschiedener Individualisierungen wurden bekannte und neue analoge Untersuchungsverfahren zur Durchführung mittels Head-Mounted-Displays implementiert und im Rahmen mehrerer Hörversuche verwendet. Hierbei wurden neben individualiserenden Faktoren wie Kopfhörerentzerrung oder ITD-Anpassung auch der Einfluss ergänzend präsentierter visueller Stimuli sowie die Einsatzmöglichkeiten von Head-Mounted-Displays zur Realisierung von Hörversuchen betrachtet. Die Ergebnisse dieser Untersuchungen sollen zur Beurteilung der Einsatzmöglichkeiten binauraler Techniken in nicht-wissenschaftlichen, multimedialen Kontexten verwendet werden. Für Fragen oder Kommentare stehe ich Ihnen gerne zur Verfügung. Mit freundlichen Grüßen, Ingo Witew -- Dipl.-Ing. Ingo Witew Research Assistant ITA - Institute of Technical Acoustics RWTH Aachen University Kopernikusstr. 5 52074 Aachen, Germany Tel +49 241 80-97994 Mobile +49 175 52 37 536 Fax +49 241 80-92214 Ingo.Witew(a)akustik.rwth-aachen.de http://www.akustik.rwth-aachen.de

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13.07.2018: Akustisches Kolloquium am ITA
by Ingo Witew 08 Jul '18

08 Jul '18

Sehr geehrte Abonnenten des Kolloquium-Newsletters, am Freitag, 13.07.2018 ist einer der nächsten Termine für das Akustische Kolloquium am Institut für Technische Akustik der RWTH Aachen. *Termin* *Vortragender* *Titel* 13.07.2018, 11:00 Pascal Palenda /BSc-Student////// / Continuous measurement of room impulse responses with Spherical Loudspeaker Arrays <http://www.akustik.rwth-aachen.de/cms/Technische-Akustik/Das-Institut/Aktue…> Der Vortrag wird im Seminarraum des Instituts (Kopernikusstraße 5) gehalten. Zusammenfassung: In the field of acoustics the result of a room impulse response (RIR) measurement is used for auralization, room reflection analysis and sound field analysis. When measuring a single RIR, the source and the receiver, have a directivity which influences the measurement. If a set of RIRs for different spatial directions is measured, we obtain a directional room impulse response (DRIR). If only one loudspeaker is used, a sequential measurement method can be employed, resulting in a virtual loudspeaker array. However, a sequential measurement results in a long measurement duration, as the loudspeaker has to be moved to the different orientations. One has to consider the time for starting and stopping. If a real loudspeaker array is used, the measurement duration can be reduced. However, to achieve the high spatial resolution, the loudspeaker array still has to be rotated. The goal is to minimize the time to complete a DRIR measurement. A proposed way is doing continuous measurements. For this method the source is rotated continuously. RIRs for different spatial directions, corresponding to the sequential measuring direction, can then be extracted from the captured signal. The continuous rotation eliminates the time for starting and stopping at the desired orientations. Further decreasing the measurement duration. However, the continuous rotation introduces further variables which have to be considered. This thesis examines the viability and limitations of continuous measurements for DRIR measurements. To evaluate the influence of the continuous rotation, different rotation speeds are used. Additionally, the measured room was varied in its reverberation time. Different excitation signals are used to measure a room using a measurement set-up with an spherical loudspeaker array. The RIRs are then recovered using different algorithms. The results of the continuous measurements are compared to the sequential measurements. The different algorithms, excitation signals and rotation speeds are compared against each other to find the preferred choice. Für Fragen oder Kommentare stehe ich Ihnen gerne zur Verfügung. Mit freundlichen Grüßen, Ingo Witew -- Dipl.-Ing. Ingo Witew Research Assistant ITA - Institute of Technical Acoustics RWTH Aachen University Kopernikusstr. 5 52074 Aachen, Germany Tel +49 241 80-97994 Mobile +49 175 52 37 536 Fax +49 241 80-92214 Ingo.Witew(a)akustik.rwth-aachen.de http://www.akustik.rwth-aachen.de

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13.07.2018: Akustisches Kolloquium am ITA
by Ingo Witew 08 Jul '18

08 Jul '18

Sehr geehrte Abonnenten des Kolloquium-Newsletters, am Freitag, 13.07.2018 ist einer der nächsten Termine für das Akustische Kolloquium am Institut für Technische Akustik der RWTH Aachen. *Termin* *Vortragender* *Titel* 13.07.2018, 11:00 Pascal Palenda /BSc-Student////// / Continuous measurement of room impulse responses with Spherical Loudspeaker Arrays <http://www.akustik.rwth-aachen.de/cms/Technische-Akustik/Das-Institut/Aktue…> Der Vortrag wird im Seminarraum des Instituts (Kopernikusstraße 5) gehalten. Zusammenfassung: In the field of acoustics the result of a room impulse response (RIR) measurement is used for auralization, room reflection analysis and sound field analysis. When measuring a single RIR, the source and the receiver, have a directivity which influences the measurement. If a set of RIRs for different spatial directions is measured, we obtain a directional room impulse response (DRIR). If only one loudspeaker is used, a sequential measurement method can be employed, resulting in a virtual loudspeaker array. However, a sequential measurement results in a long measurement duration, as the loudspeaker has to be moved to the different orientations. One has to consider the time for starting and stopping. If a real loudspeaker array is used, the measurement duration can be reduced. However, to achieve the high spatial resolution, the loudspeaker array still has to be rotated. The goal is to minimize the time to complete a DRIR measurement. A proposed way is doing continuous measurements. For this method the source is rotated continuously. RIRs for different spatial directions, corresponding to the sequential measuring direction, can then be extracted from the captured signal. The continuous rotation eliminates the time for starting and stopping at the desired orientations. Further decreasing the measurement duration. However, the continuous rotation introduces further variables which have to be considered. This thesis examines the viability and limitations of continuous measurements for DRIR measurements. To evaluate the influence of the continuous rotation, different rotation speeds are used. Additionally, the measured room was varied in its reverberation time. Different excitation signals are used to measure a room using a measurement set-up with an spherical loudspeaker array. The RIRs are then recovered using different algorithms. The results of the continuous measurements are compared to the sequential measurements. The different algorithms, excitation signals and rotation speeds are compared against each other to find the preferred choice. Für Fragen oder Kommentare stehe ich Ihnen gerne zur Verfügung. Mit freundlichen Grüßen, Ingo Witew -- Dipl.-Ing. Ingo Witew Research Assistant ITA - Institute of Technical Acoustics RWTH Aachen University Kopernikusstr. 5 52074 Aachen, Germany Tel +49 241 80-97994 Mobile +49 175 52 37 536 Fax +49 241 80-92214 Ingo.Witew(a)akustik.rwth-aachen.de http://www.akustik.rwth-aachen.de

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