Saturday, October 11 2:00 pm 5:00 pm
Session H Psychoacoustics, Perception, and Listening Tests, Part 2
H-1 Localization in an HRTF-Based Minimum Audible Angle Listening Test on a 2-D Sound Screen for GUIB ApplicationsGyörgy Wersényi, Széchenyi István University, Gyõr, Hungary
Listening tests were carried out for investigating the localization judgments of 40 untrained subjects through equalized headphones and with HRTF synthesis. The investigation was made on the basis of the former Graphical User Interface for Blind Persons (GUIB) project in order to determine the possibilities of a 2-D virtual sound screen and headphone playback. Results are presented about the capabilities and values of typical headphone playback errors as well as minimum, maximum, and average values of discrimination skills. Special localization events such as left-right and up-down symmetries, missing locations in vertical localization are also discussed. The measurement method includes a special 3-category-forced-choice MAA report on a screen-like virtual auditory surface in front of the listeners. Test signals were presented with different spectra and movement. Conclusions are drawn both for a GUIB application as well as for the binaural synthesis about the role of the fine structure of applied HRTFs.
H-2 On the Twelve Basic Intervals in South Indian Classical MusicArvindh Krishnaswamy, Stanford University, Stanford, CA, USA
We discuss various tuning possibilities for the twelve basic musical intervals used in South Indian classical (Carnatic) music. Theoretical values proposed in certain well-known tuning systems are examined. Issues related to the intonation or tuning of the notes in Carnatic music are raised and discussed as well.
H-3 A Pointing Technique with Visual Feedback for Sound Source Localization ExperimentsSylvain Choisel, Aalborg University, Aalborg, Denmark; Bang & Olufsen A/S, Struer, Denmark; Karin Zimmer, Aalborg University, Aalborg, Denmark
A new laser-pointing technique providing visual feedback is presented and compared to a more traditional method, making a mark on a line; broadband noise, speech, and a musical instrument served as sound stimuli. In localizing frontal sources (±30 degrees), both real, and amplitude-panned, in a standard listening room, the new method is shown to be more intuitive and precise, allowing for a higher consistency of responses both within and across subjects. Furthermore, the lateral displacement of the sources is overestimated in both response techniques, this inaccuracy being significantly smaller when the laser pointer is used. In a second experiment, the influence of head orientation on pointing performance toward sounds varying in frequency content is investigated. As a result, responses are not affected by moving the head toward a physical sound source but are highly sensitive to head movements when sources are panned.
H-4 Difference Limen for the Q Factor of Room ModesBruno Fazenda, Mark Avis, William Davies, University of Salford, Salford, Manchester, UK
A subjective test study was carried out in order to identify the perceptibility of changes in the Q factor of room modes. The experimental technique concentrates on the identification of difference limen for three levels of Q factor referring to modes in rooms used for critical listening. Trends show that changes in higher Q values are more perceptible than those for lower Q values. The results may be applied in decisions for treatment of modes in common listening and control rooms.
H-5 The Effects of Early Decay Time on Auditory Depth in the Virtual Audio EnvironmentJungmin Park, Han-gil Moon, Koeng-mo Sung, Seoul National University, Seoul, Korea; Dae Young Jang, Electronics and Telecommunications Research Institute, Daejun, Korea
To provide the distance information of the sound source in 3-D audio environment, we must have some information about effective distance cues and some methods to handle them properly. Through our experiments and researches, we found that C80 and EDT change systematically with source-receiver distances. We are required to validate this result physically and psychologically. This paper contains physical explanation about two parameters systematic changes and psychological tests with artificially controlled curves, which imitate different distances. With these validations, we will show the effect of early decay time on auditory depth.
H-6 Creating a Universal Graphical Assessment Language for Describing and Evaluating Spatial Attributes of Reproduced Audio EventsNatanya Ford, Francis Rumsey, University of Surrey, Surrey, Guildford, UK; Tim Nind, Harman/Becker Automotive Systems, Bridgend, Wales, UK
A Graphical Assessment Language (GAL) appears to provide the listener with a medium for describing the perceived spatial attributes of a reproduced audio event. Previous language development investigations have concluded that these spatial characteristics may be represented consistently by listeners using their own graphical descriptors. However, the ease with which these individual descriptors could be misinterpreted by a researcher was highlighted in a subsequent study; a notable problem since a primary aim of the GAL is to maintain the validity of the listeners original experience. To reduce potential ambiguities in interpretation, this paper considers the development of a common descriptive language, consolidating listeners individual descriptors into a universal set of graphical terms identified as being effective for describing the experiences of all investigation participants. The process and outcome of creating a universal GAL is described.