Download Directivity Patterns Controlling the Auditory Source Distance
What influence does the directivity of a sound source have on the perceived distance impression in a room? We propose different directivity pattern designs able to modify the auditory source distance. The idea is accompanied with a comprehensive experimental study investigating the audio effect and its behavior by auralization of directional sound source and room using a 24-channel loudspeaker ring inside an anechoic chamber. In addition to the proposed directivity designs, the study covers influence of auralized room, source-to-receiver distance, signal, and single-channel reverberation. Moreover, simple room acoustical measures perform well in predicting the new effect.
Download Auditory Perception of Spatial Extent in the Horizontal and Vertical Plane
This article investigates the accuracy with which listeners can identify the spatial extent of distributed sound sources. Either the complementary frequency bands comprising a source signal or the individual grains of a granular synthesis-based stimulus were distributed directly on discrete loudspeakers. Loudspeakers were arranged either on the horizontal or the vertical axis. The algorithms were applied on white noise, an impulse train, and a rain drops stimulus. Absolute judgments of spatial extent were obtained separately for each orientation, algorithm, and stimulus using three different magnitudes of horizontal or vertical extent. Horizontal spatial extent judgments varied systematically with physical extent for all conditions in the experiment. The correspondence between perceived and actual vertical extent was poor. The time-based synthesis algorithm resulted in significantly larger judgments of spatial extent irrespective of orientation and stimulus compared to the frequency-based algorithm.
Download Model-Based Obstacle Sonification for the Navigation of Visually Impaired Persons
This paper proposes a sonification model for encoding visual 3D information into sounds, inspired by the impact properties of the objects encountered during blind navigation. The proposed model is compared against two sonification models developed for orientation and mobility, chosen based on their common technical requirements. An extensive validation of the proposed model is reported; five legally blind and five normally sighted participants evaluated the proposed model as compared to the two competitive models on a simplified experimental navigation scenario. The evaluation addressed not only the accuracy of the responses in terms of psychophysical measurements but also the cognitive load and emotional stress of the participants by means of biophysiological signals and evaluation questionnaires. Results show that the proposed impact sound model adequately conveys the relevant information to the participants with low cognitive load, following a short training session.