zotter's Home Page

senior scientist

Tel.: ++43/316/389-3382
Fax: ++43/316/389-3171
E-mail: zotter__at__iem.at

If something's missing: also check the old page here.

interests & current work

I became chair of the new workgroup "Fachausschuss Virtuelle Akustik" within DEGA, together with Prof. Stefan Weinzierl, Prof. Sascha Spors, Prof. Bernhard Seeber as vice-chairs, and we will host ICAD 2015, http://icad.iem.at, and ICSA 2015, http://icsa2015.iem.at, in Graz. Still, I enjoy supervising students in the master program and discussing with PhD candidates a lot, but I also got project leader of OSIL (orchestrating space by icosahedral loudspeaker) :) 

My current interests are:

  • compact spherical loudspeaker arrays (sound-radiation synthesis)
  • acoustic holography and holophony lecture(requires kunstuni-login)
  • acoustic centering and spherical signal processing
  • vibration and radiation in the spherical sound field
  • surrounding spherical microphone arrays (sound-radiation capture/analysis)
  • surrounding spherical loudspeaker arrays (Ambisonics)
  • higher-order ambisonics and spherical acoustic signal representations
  • auditory aspects of spatial audio perception
  • frequency warping and spectral analysis

publications 2015 and 2014

  • Franz Zotter, Matthias Frank: "Investigations of Auditory Objects Caused by Directional Sound Sources in Rooms", [to pdf], Acta Physica Polonica A, vol. 128, nr. 1-A, p A-5--A-10, 2015.
  • Sascha Spors, Franz Zotter, Tutorial: "Foundations and Practical Aspects of Sound Field Synthesis", [pdf], 138th AES Conv., Warsaw, May 2015.
  • Franz Zotter, Matthias Frank, Christian Haar, "Spherical microphone array equalization for Ambisonics", [pdf], Fortschritte der Akustik, DAGA, Nürnberg, 2015.
  • Ben-Daniel Keller, Franz Zotter, "A New Prototype for Sound Projection", [pdf], Fortschritte der Akustik, DAGA, Nürnberg, 2015.
  • Stefan Lösler, Franz Zotter, "Comprehensive Radial Filter Design for Practical higher-order Ambisonic Recording", [pdf], Fortschritte der Akustik, DAGA, Nürnberg, 2015.
  • Hannes Pomberger, Franz Zotter,  "Uncertainty of Pressure-Based Sound Power Measurement in Semi-Anechoic Rooms due to Spatial Sampling and Near Fields", Fortschritte der Akustik, DAGA, Nürnberg, 2015.
  • Matthias Frank, Franz Zotter, Alois Sontacchi, "Producing 3D Audio in Ambisonics", [pdf], AES 57th Conference on The Future of Audio Entertainment Technology, Hollywood CA, March 2015.
  • Hannes Pomberger, Franz Zotter, Robert Höldrich, Stefan Brandl, "Estimating errors in pressure-based engine sound power measurement due to spatial sampling", [pdf] Proc. 6th Alps Adria Acoustics Congress, Graz, 2014.
  • Christian Schörkhuber, Philipp Hack, Franz Zotter, Markus Zaunschirm, Alois Sontacchi, "Localization of multiple acoustic sources with a distributed array of unsynchronized first-order ambisonics microphones", Proc. 6th Alps Adria Acoustics Congress, Graz, 2014.
  • Nicolas Epain, Craig T. Jin, Franz Zotter, "Ambisonic Decoding with Constant Angular Spread", EAA Symposium on Auralization and Ambisonics, Berlin, April 2014; paper in: Acta Acustica united with Acustica, vol. 100, no. 5, pp. 928-936, 2014.
  • Georgios Marentakis, Franz Zotter, Matthias Frank, "Vector-Base and Ambisonic Amplitude Panning: A Comparison Using Pop, Classical, and Contemporary Music", EAA Symposium on Auralization and Ambisonics, Berlin, April 2014; paper in: Acta Acustica united with Acustica, vol. 100, no. 5, pp. 945-955, 2014.
  • Franz Zotter, Matthias Frank, Andreas Fuchs, Daniel Rudrich, "Preliminary study on the perception of orientation-changing directional sound sources in rooms," abstract submitted to Forum Acusticum, Krakow, [pdf], September 2014.
  • Gerriet K. Sharma, Franz Zotter, Matthias Frank, "Orchestrating wall reflections in space by icosahedral loudspeaker: findings from first artistic research exploration," submitted to ICMC-SMC, Athens, [pdf], September 2014.
  • Alois Sontacchi, Matthias Frank, Franz Zotter, Christian Kranzler, Stephan Brandl, "Sound Optimization for Downsized Engines," 8th ISNVH, Graz, July 2014.
  • Matthias Frank, Franz Zotter, Alois Sontacchi, Stephan Brandl, Christian Kranzler, "Comprehensive array measurements of in-car sound field in magnitude and phase for active sound generation and noise control," 8th ISNVH, Graz, July 2014.
  • Franz Zotter, Matthias Frank, Matthias Kronlachner, Jung-Woo Choi, "Efficient Phantom Source Widening and Diffuseness in Ambisonics", [to pdf], EAA Symposium on Auralization and Ambisonics, Berlin, April 2014.
  • Markus Zaunschirm, Franz Zotter, "Measurement-based Modal Beamforming using Planar Circular Microphone Arrays", [pdf], EAA Symposium on Auralization and Ambisonics, Berlin, April 2014.
  • Florian Wendt, Matthias Frank, Franz Zotter, "Panning with Height on 2, 3, and 4 Loudspeakers", [pdf], 2nd International Conference on Spatial Audio (ICSA), Erlangen, February 2014.
  • Matthias Kronlachner, Franz Zotter, "Spatial transformations for the enhancement of Ambisonic recordings", [pdf], 2nd International Conference on Spatial Audio (ICSA), Erlangen, February 2014.
  • entire list of publications including things between 2003 and 2014


  • Franz Zotter, "Analysis and Synthesis of Sound-Radiation with Spherical Arrays", Doctoral Thesis, Institute of Electronic Music and Acoustics, University of Music and Performing Arts Graz, [pdf] [pdf], 2009.
  • Diplomarbeit: "Unterdrückung hörbarer Störgeräusche in Echtzeitsystemen", [pdf], 2004.


Lecture on diffraction 2014 [ppt] and "5D" room impulse responses [zip:ppt]. ERASMUS-TA, ITA, RTWH-Aachen, Gradientenmikrofone hoher Ordnung, in Elektroakustik / akustische Messtechnik, [pdf], Jan., 2012. ERASMUS-TA, Fachgebiet Audiokommunikation, TU-Berlin, Virtuelle Akustik: Holografie mit dem Rayleighintegral, sphärische Holografie/Holofonie, Jun., 2012.
Acoustic Holography and Holophony (Lecture):
W1011, W1112, W1213, W1314, W1415
Algorithms in Acoustics and Computer Music 2 (Lab/Seminar):
S08, W0809, W0910, W1011, W1112, W1213, W1314, W1415,
Acoustic Holography and Holophony / Acoustic Measurement Techniques 2 (Lab):
S08, S09, S10, S11, S12, S13, S14

advised students' works

Master/Diploma theses:

  • Philipp Alexaner Hack. "Multiple Source Localization with Distributed Tetrahedral Microphone Arrays", [pdf], 2015. (WKO Scholarship 2014)
  • Ben-Daniel Keller. "Development of a Sound Projection Prototype", [pdf], 2015. (WKO Scholarship 2014, DEGA Student Grant 2015, DAGA Poster Award 2015)
  • Juan Andrés Ureta Staackmann. "Simulation of Room Transfer Functions With Directivity Patterns On The Basis Of Room Modes", [pdf], 2014.
  • Stefan Lösler. "MIMO-Rekursivfilter für Kugelarrays", [pdf], 2014. (DEGA Student Grant 2015, DAGA Poster Award 2015)
  • Matthias Kronlachner. "Spatial Transformations for the Alteration of Ambisonic Recordings", [pdf], 2014.
  • Ander Gaspar Perez Palacios. "Measurement and evaluation of room impulse response measurements performed with a flexible highly directive source", thesis in collaboration with ITA RWTH-Aachen, [pdf], 2014
  • Clara Hollomey. "Real-Time Spectrogram Inversion – Retrieving Primal Signals", [pdf], 2014.
  • Florian Wendt. "Untersuchung von Phantomschallquellen vertikaler Lautsprecheranordnungen", [pdf], 2013.
  • Florian Pausch. "A Rigid Double Cone Microphone Array Prototype", [pdf], 2013. (Gold in AES Student Design Competition 2013)
  • Philipp Schmidt. "Improvements in Localisation of Planar Acoustic Holography", [pdf], 2012. (DEGA student Prize 2014)
  • Fabio Kaiser. "Modal Analysis of Rigid Microphone Arrays using Boundary Elements", [pdf], 2012.
  • Markus Zaunschirm."Modal beamforming using planar circular microphone arrays", 2012.
  • Johannes Zaar. "Phase Unwrapping for Spherical Interpolation of Head-Related Transfer Functions", [pdf], 2011.
  • Nadine Kroher. "Acoustic feedbacks of loudspeaker-room-microphone environments with directivity", [pdf], 2011.
  • Ralf Baumgartner. "Time Domain Fast-Multipole Translation for Ambisonics", [pdf], 2011.
  • Thomas Kößler. "Kugelkappenförmige Mikrofonanordnung zur 3-dimensionalen Erfassung des Schallfeldes", [pdf], 2011.
  • Sebastian Preis. "Richtungshörmodell mit Elevation und Korrektur der Mehrdeutigkeiten", [pdf], 2011.
  • Wolfgang Nemitz. "Simulation and design of a measurement tube for microphones", [to pdf], 2010.
  • Daniel Deboy. "Acoustic Centering and Rotational Tracking in Surrounding Spherical Microphone Arrays", [pdf], 2010. (DEGA Student Prize 2011)
  • Michael Kerscher. "Compact Spherical Loudspeaker Array for Variable Sound-Radiation", [pdf], 2010.
  • Peter Plessas. "Rigid sphere microphone arrays for spatial recording and holography", [to pdf], 2009.
  • Fabian Hohl. "Kugelmikrofonarray zur Abstrahlungsvermessung von Musikinstrumenten", [to pdf], 2009.
  • Matthias Frank. "Perzeptiver Vergleich von Schallfeldreproduktionsverfahren unterschiedlicher räumlicher Bandbreite", [to pdf], 2009.
  • Hannes Pomberger. "Angular and Radial Directivity Control for Spherical Loudspeaker Arrays", [pdf], 2008.
  • Daniel Hofer. "Implementierung eines 64 Kanal Mikrofonarrays", [to pdf], 2008.

"Toningenieur" projects:

  • Stefan Lösler. "Schallfeldspezifische Entzerrung bei Radialfiltern begrenzter Dynamik für das Eigenmike", [pdf], 2013.
  • Sebastian Süss. "Auffinden von Ursignalen aus Aufnahmen umgebender kugelförmiger Mikrofonanordnungen", [to pdf], 2011.
  • Johannes Zaar. "Vermessung von Außenorhübertragungsfunktionen mit reziproker Messmethode", [pdf], 2010.
  • Stefan Richardt. "Implementierung eines Modells zur Messung und Darstellung binauraler Lokalisation (Implementation of a model for measuring and illustrating binaural sound localization)", [pdf], 2010.
  • Christian Siller. "Beamforming mit einem Miniatur-Line-Arrays", [pdf], 2010.
  • Sebastian Rieck. "Implementierung einer Ausfallsverschleierung mittels spektraler Signalmodellierung", [pdf], 2009.
  • Georg Koller. "Verbesserung der virtuellen Akustik für Kopfhörer durch Berücksichtigung von Schulterdrehungen relativ zum Kopf", [pdf], 2008.
  • Matthias Frank. "Hörversuch zur Lokalisation bei verschiedenen Ambisonics-Decodern", [pdf], 2008.
  • Margherita Jammer. "Modeling sounds of Gamelan Instruments with Exponentially Decaying Sinusoids", [pdf], 2008.
  • Fabian Hohl. "Sound and Radiation Analysis of Multichannel Gamelan Sound Samples", [pdf], 2008.
  • Peter Reiner, Christian Jochum. "Measurement and Evaluation of Crosstalk within an Icosehedral Loudspeaker Array", [pdf], 2007.
  • Christian Jochum, Peter Reiner. "Driving Filters for the Icosahedral Louspeaker Array", [pdf], 2007.

Bachelorarbeit (Betreuer: Alois Sontacchi)

  • Robert Baumgartner, Elmar Messner. "Auswirkung der Abstrahlcharakteristik auf die Klangfarbe von Querflöten und Saxofonen", [to pdf], 2010.


I'm occasionally contributing to the "iem" external libraries in the CVS repository of pure-data. I wrote the "pdoctave" (2005) external to connect pd with octave/MATLAB over pipe and shm under linux, and added a few objects to the "iemmatrix".