Reducing reversal errors in localizing the source of sound in virtual environment without head tracking

International audienceThis paper presents a study about the effect of using additional audio cueing and Head-Related Transfer Function (HRTF) on human performance in sound source localization task without using head movement. The existing techniques of sound spatialization generate reversal errors. We intend to reduce these errors by introducing sensory cues based on sound effects. We conducted and experimental study to evaluate the impact of additional cues in sound source localization task. The results showed the benefit of combining the additional cues and HRTF in terms of the localization accuracy and the reduction of reversal errors. This technique allows significant reduction of reversal errors compared to the use of the HRTF separately. For instance, this technique could be used to improve audio spatial alerting, spatial tracking and target detection in simulation applications when head movement is not included

The pupil response is sensitive to divided attention during speech processing

AbstractDividing attention over two streams of speech strongly decreases performance compared to focusing on only one. How divided attention affects cognitive processing load as indexed with pupillometry during speech recognition has so far not been investigated. In 12 young adults the pupil response was recorded while they focused on either one or both of two sentences that were presented dichotically and masked by fluctuating noise across a range of signal-to-noise ratios. In line with previous studies, the performance decreases when processing two target sentences instead of one. Additionally, dividing attention to process two sentences caused larger pupil dilation and later peak pupil latency than processing only one. This suggests an effect of attention on cognitive processing load (pupil dilation) during speech processing in noise

Calibration of consonant perception to room reverberation

Purpose: We examined how consonant perception is affected by a preceding speech carrier simulated in the same or a different room, for different classes of consonants. Carrier room, carrier length, and carrier length/target room uncertainty were manipulated. A phonetic feature analysis tested which phonetic categories are influenced by the manipulations in the acoustic context of the carrier. Method: Two experiments were performed, each with nine participants. Targets consisted of 10 or 16 vowel– consonant (VC) syllables presented in one of two strongly reverberant rooms, preceded by a mul ti pl e-VC carri er presented in either the same room, a different reverberant room, or an anechoic room. In Experiment 1, the carrier length and the target room randomly varied from trial to trial, whereas in Experiment 2, they were fixed within a block of trials. Results: Overall, a consistent carrier provided an advantage for consonant perception compared to inconsistent carriers, whether in anechoic or differently reverberant rooms. Phonetic analysis showed that carrier inconsistency significantly degraded identification of the manner of articulation, especially for stop consonants and, in one of the rooms, also of voicing. Carrier length and carrier/target uncertainty did not affect adaptation to reverberation for individual phonetic features. The detrimental effects of anechoic and different reverberant carriers on target perception were similar. Conclusions: The strength of calibration varies across different phonetic features, as well as across rooms with different levels of reverberation. Even though place of articulation is the feature that is affected by reverberation the most, it is the manner of articulation and, partially, voicing for which room adaptation is observed. © 2021 American Speech-Language-Hearing Association

Monaural Source Separation Using Spectral Cues

The acoustic environment poses at least two important challenges. First, animals must localise sound sources using a variety of binaural and monaural cues; and second they must separate sources into distinct auditory streams (the “cocktail party problem”). Binaural cues include intra-aural intensity and phase disparity. The primary monaural cue is the spectral filtering introduced by the head and pinnae via the head-related transfer function (HRTF), which imposes different linear filters upon sources arising at different spatial locations. Here we address the second challenge, source separation. We propose an algorithm for exploiting the monaural HRTF to separate spatially localised acoustic sources in a noisy environment. We assume that each source has a unique position in space, and is therefore subject to preprocessing by a different linear filter. We also assume prior knowledge of weak statistical regularities present in the sources. This framework can incorporate various aspects of acoustic transfer functions (echos, delays, multiple sensors, frequency-dependent attenuation) in a uniform fashion, treating them as cues for, rather than obstacles to, separation. To accomplish this, sources are represented sparsely in an overcomplete basis. This framework can be extended to make predictions about the neural representations required to separate acoustic sources

Contributions of binaural information to the separation of different sound sources

Binaural hearing aids potentially provide binaural cues that can improve the dectability and the spatial separation of multiple sound sources. This paper considers the use of binaural cues and the resultant spatial percepts on listeners ability to separate simultaneous sound sources. In continuous noise backgrounds or backgrounds with multiple talkers, the main problem is the detection of the individual acoustic components. On the other hand, if a single masking sound is very similar to the target, and both target and mask are spectro-temporally sparse, as is the case with speech, the main problem, at least for listeners with normal hearing, is to decide whether a particular spectro-temporal feature belongs to the target source and to track that source across time. Although the subjective location of a sound source can help in grouping features across time, its effect is most easily observed in the absence of other differences between the sound sources