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.

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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.

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