The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.

Application of Spatial Sound Reproduction in Virtual Environments – Experiments in Localization, Navigation, and Orientation

Matti Gröhn

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Computer Science and Engineering for public examination and debate in Auditorium T1 at Helsinki University of Technology (Espoo, Finland) on the 24th of May, 2006, at 12 noon.

Overview in PDF format (ISBN 952-5520-16-1)   [1910 KB]
Dissertation is also available in print (ISBN 952-5520-15-3)


The topic of this research was spatial sound reproduction in a cave-like virtual room (EVE) of the Helsinki University of Technology. Spatial sound reproduction is widely used, for example, in movie industry and computer games. In virtual environments it has been employed less than visual and tactile modalities. There are several common tasks in virtual reality applications in which spatial audio could be used. This thesis concentrates on localization, navigation, and orientation.

This research is one of the first studies in localization accuracy of loudspeaker reproduction in a virtual room. In the localization experiments, subjects pointed to the perceived direction of the sound source. According to the measurements, the achieved localization accuracy was at the same level as presented in literature for headphone reproduction. Localization of the moving sound sources was not as accurate as localization of the static sources.

In the navigation experiments, the task of the users was to move from waypoint to waypoint according to the visual and auditory cues. In the first experiment, auditory, visual, and audio-visual conditions were tested, and in the second experiment, different auditory cues were compared. Audio-visual navigation was the most efficient. Analysis of the travel paths indicated that an auditory cue was used at the beginning to locate direction of the next target, and a visual cue was used in the final approach to the target. In addition, all the subjects could navigate using the auditory cue alone. Auditory navigation performance increased when additional information about the distance and elevation of the target was included in auditory cues.

In the orientation experiment, subjects flew a predefined route inside an architectural model. Their task was to keep the model as balanced as possible during their flight. Three auditory artificial horizons were designed using "ball on a plate" metaphor. The sound was played from the direction towards which the virtual world was tilted. According to test results, the designed horizons helped the user to keep the model better in an upright position than without them.

Additional results included how the design of the virtual room and direction indication method affect on measured localization accuracy.

This thesis consists of an overview and of the following 8 publications:

  1. M. Gröhn, T. Lokki, L. Savioja, and T. Takala. Some aspects of role of audio in immersive visualization. In: Visual Data Exploration and Analysis VIII, Proceedings of SPIE, Vol. 4302, pages 13-22, San Jose, USA, January 2001. © 2001 Society of Photo-Optical Instrumentation Engineers (SPIE). By permission.
  2. M. Gröhn. Is audio useful in immersive visualization? In: Stereoscopic Displays and Virtual Reality Systems IX, Proceedings of SPIE, Vol. 4660, pages 411-421, San Jose, USA, January 2002. © 2002 Society of Photo-Optical Instrumentation Engineers (SPIE). By permission.
  3. M. Gröhn, T. Lokki, and T. Takala. Static and dynamic sound source localization in a virtual room. In: Proceedings of the AES 22nd International Conference on Virtual, Synthetic and Entertainment Audio, pages 337-344, Espoo, Finland, June 2002. © 2002 Audio Engineering Society (AES). By permission.
  4. M. Gröhn. Localization of a moving virtual sound source in a virtual room, the effect of a distracting auditory stimulus. In: Proceedings of the 8th International Conference on Auditory Display (ICAD 2002), pages 394-402, Kyoto, Japan, 2.-5. July 2002. © 2002 by author.
  5. M. Gröhn, T. Lokki, and T. Takala. Localizing sound sources in a cave-like virtual environment with loudspeaker array reproduction. Presence: Teleoperators and Virtual Environments, Vol. 16, 19 pages, 2007, accepted for publication.
  6. M. Gröhn, T. Lokki, and T. Takala. Comparison of auditory, visual, and audiovisual navigation in a 3D space. In: Proceedings of the 9th International Conference on Auditory Display (ICAD 2003), pages 200-203, Boston, USA, 6.-9. July 2003. Reprinted in ACM Transactions on Applied Perception, Vol. 2, Nr. 4, pages 564-570, October 2005.
  7. T. Lokki and M. Gröhn. Navigation with auditory cues in a virtual environment. IEEE Multimedia, Vol. 12, Nr. 2, pages 80-86, April-June 2005. © 2005 IEEE. By permission.
  8. M. Gröhn, T. Lokki, and T. Takala. An orientation experiment using auditory artificial horizon. In: Proceedings of the 10th International Conference on Auditory Display (ICAD 2004), Sydney, Australia, 6.-9. July 2004, 6 pages. © 2004 by authors.

Errata of publications 2 and 3

Keywords: spatial sound reproduction, virtual reality, localization of sound sources, navigation, orientation

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© 2006 Helsinki University of Technology

Last update 2011-05-26