IKA-SIM

The Institute of Communication Acoustics has a long history in research and development of AVE systems (e.g. Lehnert and Blauert 1989). In (Blauert et al. 2000, and Djelani et al. 2000) the DSP-based real-time AVE system SCATIS is presented and evaluated. The present PC-based implementation is the interactive AVE system IKA-SIM, in which the position of the listener and various sound sources can be controlled in real-time (Silzle et. al 2004). Subject of current work is the extension of IKA-SIM with network functionality and by this the possibility to use it as a backend for Web-based applications. IKA-SIM is also used in the EU project HEARCOM in conjunction with screening tests for hearing impaired listeners in adverse conditions.

In recent research activities we investigated strategies to find an optimal set of parameters in the physical and the perceptual domain which results in a good compromise between listening experience and implementation effort (Silzle 2005). One part of this optimisation process is to find or generate the best non-individual head-related transfer functions (HRTF), which are one important part for the headphone reproduction of an AVE (Silzle 2002 and 2003). Another research activity is a 3D loudspeaker reproduction, using a new method for elevation panning with 14 channels (Gretzki and Silzle 2004).

A lot of applications use the AVE approach, like e.g. man-machine communication, teleconferencing, virtual acoustics, hi-fi, computer games, television, cinema and many more. The complexity of the technical implementation differ significantly between different applications and implementations. Most of today's Virtual Reality applications mainly focus on visual feedback. However, including auditory feedback can significantly improve the perception of being immersed in a Virtual Environment.


Listening examples:

Four different sound sources in standard reproduction (localisation inside the head)
Four different sound sources treated with IKA-SIM (natural localisation outside the head)


Figure 1
Fig. 1: Mirror sources in a sound studio environment and sound traces in the concert hall Musikvereinssaal in Vienna simulated with the interactive real-time software "IKA-SIM"

 

References

Blauert J (1997). Spatial Hearing, The Psychophysics of Human Sound Localisation (Second edition), MIT Press, (Original German version 1974)

Blauert J ed. (2005). Communication Acoustics, Springer

Blauert J, Lehnert H, Sahrhage J, Strauss H (2000). An Interactive Virtual-Environment Generator for Psychoacoustic Research. I: Architecture and Implementation, Acustica – acta acustica, Vol 86, pp. 94-102

Djelani T, Pörschmann C, Sahrhage J and Blauert J (2000). An Interactive Virtual-Environment Generator for Psychoacoustic Research II: Collection of Head-Related Impulse Responses and Evaluation of Auditory Localization, Acustica – acta acustica Vol.86, pp. 1046-1053

Gretzki R and Silzle A (2004). A New Method for Elevation Panning Reducing the Size of the Resulting Auditory Events, Proc. 7. Congrès Français d'Acoustique / 30. Dtsch. Jahrestg. f. Akust. (CFA/DAGA'04), F-Strassburg

Lehnert H, and Blauert J (1989). A concept for binaural room simulation. In: Proc. IEEE ASSP Worksh. Application of Signal Processing to Audio and Acoustics, New Paltz NY

Silzle A (2002). Selection and Tuning of HRTFs, 112th AES Convention, Munich, Germany, #5595

Silzle A (2003). Quality of Head-Related Transfer Functions - Some Practical Remarks, First ISCA Tutorial & Research Workshop on Auditory Quality of Systems, Akademie Mont-Cenis, Germany

Silzle A, Novo P, Strauss H (2004). IKA-SIM: A System to Generate Auditory Virtual Environments, 116th AES Convention, Berlin, Germany, #6016

Silzle A (2005). Optimierungsmethode für Systeme zur Generierung von auditiven virtuellen Umgebungen (optimisation method for systems to generate auditory virtual environments), 31. Dtsch. Jahrestg. f. Akust. (DAGA ,05), München, Germany