We present a novel method to adjust the perceived width of a phantom source by varying the deterministic inter channel time difference (ICT D) in a pair of signals over frequency. In contrast to given literature that focuses on random phase over frequency, our paper considers a deterministic approach that is open to a more systematic evaluation. Two allpass structures are described, finite impulse response (FIR) and infinite impulse response (IIR), for phase-based phantom source widening and evaluated in a formal listening test. Varying ICT D over frequency essentially alters the inter-aural cross correlation coefficient at the ears of a listener and in this way provides a robust way to control the auditory source width. The subjective evaluation results fully support our observations for both noise and speech signals.

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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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