9:00 am

B-1 Impact of Artificial Reverberation on Perceived Sound Localization during a Headphone Listening Task

James J. McTigue, Euphonix, Inc., Palo Alto, CA, USA

A commercially available acoustic simulation software with integral normalized head-related transfer function (HRTF) was utilized to create virtual sound spaces, reverberation, and auralization. Four men and four women with self-reported normal hearing were tested individually in a room specifically designed for audiological research. Stimuli were presented via headphones, and subjects responded via a custom graphical user interface (GUI). Azimuth had a significant effect on all of the dependent variables. Gender differed significantly with respect to distance judgement. Room type significantly affected elevation judgement. In addition, there were interactions between gender and azimuth (azimuth judgment), room and reverberation type (distance judgment), and reverberation type and azimuth (distance judgment).

Convention Paper 5413

9:30 am

B-2 Research on the Improvement of Naturalness in Auralization

Chulmin Choi, Lae-Hoon Kim, and Koeng-Mo Sung, Seoul National University, Seoul, Korea
Sejin Doo, Dong-Ah Broadcasting College, Kyonggi, Korea
Yangki Oh, Mokpo National University, Chonnam, Korea

Measuring and reproducing spatial impressions of a sound field has been an important issue in auditorium acoustics for the study of existing auditory spaces. The directional impulse response, which contains spatial information, can be measured and auralized. Typical method for synthesizing binaural impulse response from the measured data assumes each reflection as an ideal impulse with measured time delay and level. This makes a difference between auralized situation and real situation because the shape of each reflection contains the information of sound color. The authors propose an improved auralization algorithm, which uses real reflection samples from measured impulse response. In this paper the authors measured the early reflection profile of a hall using 5-microphones system and synthesized the binaural impulse response using proposed algorithm.

Convention Paper 5414

10:00 am

B-3 More About This Reverberation Science: Perceptually Good Late Reverberation

Matti Karjalainen and Hanna Järveläinen, Helsinki University of Technology, Espoo, Finland

The perceptual aspects of reverberation are less well known than the acoustic principle itself and its DSP-based simulation in artificial reverberators. In this paper a series of psychoacoustic experiments are reported, along with their interpretation using auditory modeling in order to reveal the underlying principles of late reverberation perception. Motivated by the results, a simple technique for reverb design is proposed.

Convention Paper 5415

10:30 am

B-4 Time-Frequency Methods for Virtual Microphone Signal Synthesis

Athanasios Mouchtaris and Chris Kyriakakis, University of Southern California, Los Angeles, CA, USA

Multichannel audio offers significant advantages for music reproduction that include the ability to provide better localization and envelopment, as well as reduced imaging distortion. Consumer media, such as DVD-Audio and SACD, allow the delivery of multichannel program material today. However, although there are thousands of music recordings available in mono or two-channel stereo, only a handful have been recorded using microphone techniques that would allow subsequent multichannel rendering. In this paper the authors propose a new method that is capable of synthesizing the required microphone signals from a smaller set of signals recorded in a particular venue. These synthesized "virtual" microphone signals can be used to produce multichannel recordings that accurately capture the acoustics of the particular venue. Applications of the proposed system include remastering of existing monophonic and stereophonic recordings for multichannel rendering as well as transmission of multichannel audio over the current Internet infrastructure.

Convention Paper 5416

11:00 am

B-5 An Interdisciplinary Integration of Reverberation

Barry Blesser, Blesser Associates, Belmont, MA, USA

Artificial reverberator algorithms should be evaluated using stochastic methods. The reverberation impulse response is separated into the early part, containing the unique spatial personality, and the late part, containing the statistically random process. Stochastic models collapse the large amount of data in the late reverberation into a small number of temporal and spectral metrics. When they match the perceptual criteria, the process is transparent. This provides a scientific method for achieving high quality without the need for extensive ad hoc listening experiments. Other disciplines, notably statistical physics, psychoacoustics, architecture and music, contribute critically important insights. Some of the apparent paradoxes converge into a coherent theory using this approach.

Convention Paper 5468