Last Updated: 20050418, meiTuesday, May 31, 14:00 — 17:00
Chair: William Martens, McGill University - Montreal, Quebec, Canada
S-1 Numerical Head Model to HRTF Simulation—Przemyslaw Plaskota, Andrzej B. Dobrucki, Wroclaw University of Technology - Wroclaw, Poland
In this paper a numerical model of a human head is presented. This model is used for calculations of Head-Related Transfer Function (HRTF). Morphological features of the human head as well as the structure of outer ear are described. Some of these features are used in the numerical model, other ones are passed over. The possibilities of parameterization of the model according to the individual anthropological features are presented.
Convention Paper 6510 (Purchase now)
S-2 Thresholds for Auditory-Tactile Asynchrony—Durand Begault, Bernard Adelstein, NASA Ames Research Center - Moffett Field, CA, USA; Byran McClain, San Jose State University Foundation - San Jose, CA, USA; Mark Anderson, QSS Group, Inc.
Realistic simulation and perceived "immersion" within a multimodal display for telecommunication and entertainment can be enhanced, or completely degraded, as a function of inter-modal timing asynchronies between the multimodal rendering systems (system-system asynchrony). Tolerable asynchronies have been extensively examined for auditory-visual stimuli but less so for auditory-haptic cues. Data are presented from two experiments where auditory stimuli are varied in time of arrival (lead-tag) relative to a tactile pulse. Results indicate variability between participants in terms of overall thresholds. Generally, thresholds are lower when auditory stimuli lead haptic stimuli, compared to the opposite condition.
Convention Paper 6511 (Purchase now)
S-3 Effect of Direction on Loudness in Individual Binaural Synthesis—Ville Pekka Sivonen, Aalborg University - Aalborg, Denmark, and Brüel & Kjær Sound & Vibration Measurement A/S, Nærum, Denmark; Pauli Minnaar, Wolfgang Ellermeier, Aalborg University - Aalborg, Denmark
The effect of sound incidence angle on loudness was investigated using individual binaural synthesis. In the synthesis, individual head-related transfer functions and headphone equalization were used. Acoustical measurements were carried out in order to verify the binaural synthesis. In a listening test, narrow-band noises at various center frequencies synthesized from different directions were presented to the listeners. Their task was to match the loudness of these stimuli in an adaptive procedure to a reference noise synthesized with a frontal incidence angle. Considerable variation in the directional loudness matches between center frequencies and listeners was obtained. The results were compared to an earlier study using the same experimental design but with stimuli being played back over loudspeakers. The comparison shows that the patterns of directional loudness are well retained in the binaural synthesis, the difference between playback over loudspeakers, and the binaural synthesis in terms of directional loudness perception being insignificant.
Convention Paper 6512 (Purchase now)
S-4 The Three-Dimensional Acoustic Environment as Depth Cue in Sound Recordings—Håkan Ekman, Jan Berg, Luleå University of Technology - Piteå, Sweden
The research on the perceived depth in a sound image mainly concerns the distance to the source. Observations on the three-dimensional environment is generally of an anecdotal nature. In order to enhance the perceived spatial quality of reproduced sound it is important to know more about how depth in recordings is perceived and generated. The aim of this paper is to put focus on the concept of depth, i.e., define what sound engineers mean by depth in recordings. This has been studied through interviews with sound engineers. The most common thought is that depth is equal to the distance to the sound sources. This definition is still not enough to encompass the whole concept of depth. The experienced environment in front of the listener may also affect the perceived depth. This result will be compared with the existing research.
Convention Paper 6513 (Purchase now)
S-5 Evaluation of Spatial Enhancement Systems for Stereo Headphone Reproduction by Preference and Attribute Rating—Gaëtan Lorho, Nokia Corporation - Helsinki, Finland
This paper presents some results from an ongoing study on the perception of sound reproduced over headphones. The quality of spatial enhancement systems for stereo headphone reproduction was investigated with two different methods. Five musical programs were processed with seventeen algorithms representing different approaches to spatial enhancement for headphone reproduction. A preference test was designed to compare the performance of these systems with respect to an unprocessed stereo reference. An attribute test was also performed by a panel of ten assessors using a subset of eight algorithms for two of the musical programs. The sixteen attributes employed for this evaluation were developed during a descriptive analysis experiment designed to explore the perceptual characteristics of sound reproduced over headphones. The results of the two subjective studies are described and compared.
Convention Paper 6514 (Purchase now)
S-6 Fundamental Frequency Coding in NofM Strategies for Cochlear Implants—Waldo Nogueira, University of Hannover - Hannover, Germany; Andreas Büchner, Hörzentrum Hannover - Hannover, Germany; Bernd Edler, University of Hannover - Hannover, Germany
Current speech processing strategies for cochlear implants are based on decomposing the audio signals into multiple frequency bands each one associated with one electrode. However, these bands are relatively wide to accurately encode tonal components of audio signals. To improve the encoding of tonal components and performance in cochlear implants, a new signal processing strategy has been developed. The technique is based on the principle of a so-called NofM strategy. These strategies stimulate fewer channels (N) per cycle than active electrodes (M) (NofM; N < M). However, the new strategy incorporates a fundamental frequency estimator which is used to emphasize the periodic structure of tonal components. The new technique was acutely tested on cochlear implant recipients.
Convention Paper 6515 (Purchase now)
©2005 Audio Engineering Society, Inc.