Influence of visual setting on sound ratings in an urban environment

We assessed how listener's judgments of a set of urban sound environments were affected by co-occurring visual settings. In artificial audiovisual environments, subjects rated eight urban sound environments (recordings) when they were associated with five visual settings (four color slides varying in degree of urbanization and a control condition with no slide), along two sound scales (Unpleasant-Pleasant and Stressful-Relaxing). In general, the more urban the visual setting, the more negative the sound ratings. However, this influence depended on the type of sound. It was marked for recordings which did not include human sounds (particularly strong for bird song and weaker for traffic noise), but was absent for all recordings which included human sounds (footsteps and voices). Results are discussed in terms of the degree of matching between visual and sound information, and the degree of implication of the perceiver with these sound environments.     

Crossmodal influences on visual perception

Vision is generally considered the dominant sensory modality; self-contained and independent of other senses. In this article, we will present recent results that contradict this view, and show that visual perception can be strongly altered by sound and touch, and such alterations can occur even at early stages of processing, as early as primary visual cortex. We will first review the behavioral evidence demonstrating modulation of visual perception by other modalities. As extreme examples of such modulations, we will describe two visual illusions induced by sound, and a visual illusion induced by touch. Next, we will discuss studies demonstrating modulation of activity in visual areas by stimulation of other modalities, and discuss possible pathways that could underpin such interactions. This will be followed by a discussion of how crossmodal interactions can affect visual learning and adaptation. We will review several studies showing crossmodal effects on visual learning. We will conclude with a discussion of computational principles governing these crossmodal interactions, and review several recent studies that demonstrate that these interactions are statistically optimal.     

动态水景声喜好度实验研究

采集不同地域环境中的动态水景声景观数据,采用里克特5级量表,通过实验室实验研究水景声喜好度与声音物理特征、水景形态与环境视觉喜好度和被试等因素的关系。分析发现:单听水景声音时,声喜好度与水景声音A声级显著负相关(r_p=-0.981,p<0.01),与瞬时变率显著正相关(r_p=0.720,p<0.05)。当谱质心与A声级和瞬时变率显著相关时,谱质心与声喜好度也显著负相关(r_p=-0.867,p<0.01);放映水景形态和环境默片,评价其视觉喜好度;将水景声音分别与形态、环境视频同时播放再评价其声喜好度,发现视觉喜好度较高的水景形态和环境能够明显提高大流速流量水景的声喜好度,视觉喜好度较低的水景形态和环境反而降低了小流速流量水景的声喜好度;男女生对水景声喜好度的评价有显著差异,本地学生对黑虎泉声喜好度评价比非本地学生高。因此,水景声喜好度受其声音物理指标、形态和环境视觉因素及被试自身等因素的影响。     

Instruction’s effect on semantic scale ratings of interior car sounds

The aim of the study presented here is to examine the effects of instructions on the perception of a sequence of interior car sounds in three different conditions. In each condition, participants listened to the same sound sequence, but the type of information given during the instruction phase, prior to the listening test, were different. In the first condition, a group of participants listens to the sound sequence without any external information except that the sound sequence was recorded inside a car. In the second condition, another group of participants was informed by a text of the successive events that are presented in the sound sequence. In the third condition, participants were informed first by the same text as in condition 2, and then by several pictures showing the different steps that could be heard from the beginning to the end of the sound sequence. Each of the three groups of subjects participated in three tasks: an identification task, a recognition task, and a semantic judgment task using twelve verbal attributes. We assessed how listeners’ judgments of the sound sequence were affected by external information. Results show that the effect is dependant on the type of verbal attribute and on the combination of external information. The verbal information, provided without visual information in condition 2, improves the identification and recognition scores, and thus influences positively the comprehension of the sound sequence and the feeling of immersion. The added visual information, in condition 3, does not change the identification scores, but affects judgements on the pleasantness scale. It appears that the perception of the sound sequence was influenced by visual cues. This study reveals that the format of instructions influences perceptive judgments of the sound sequence tested, but globally factors accounting for the participants’ perception across the three conditions are not modified.     

Who is whistling? Localizing and identifying phonating dolphins in captivity

Acoustic communication through whistles is well developed in dolphins. However, little is known on how dolphins are using whistles because localizing the sound source is not an easy task. In the present study, the hyperbola method was used to localize the sound source using a two-hydrophone array. A combined visual and acoustic method was used to determine the identity of the whistling dolphin. In an aquarium in Mexico City where two adult bottlenose dolphins were housed we recorded 946 whistles during 22 days. We found that a dolphin was located along the calculated hyperbola for 72.9% of the whistles, but only for 60.3% of the whistles could we determine the identity of the whistling dolphin. However, sometimes it was possible to use other cues to identify the whistling dolphin. It could be the animal that performed a behavior named “observation” at the time whistling occurred or, when a whistle was only recorded on one channel, the whistling dolphin could be the animal located closest to the hydrophone that captured the whistle. Using these cues, 15.4% of the whistles were further ascribed to either dolphin to obtain an overall identification efficiency of 75.7%. Our results show that a very simple and inexpensive acoustic setup can lead to a reasonable number of identifications of the captive whistling dolphin: this is the first study to report such a high rate of whistles identified to the free swimming, captive dolphin that produced them. Therefore, we have a data set with which we can investigate how dolphins are using whistles. This method can be applied in other aquaria where a small number of dolphins is housed; though, the actual efficiency of this method will depend on how often dolphins spend time next to each other and on the reverberation conditions of the pool.     

Effects of acoustical noise on annoyance, performance and fatigue during mental memory task

This paper describes the effects of meaningful and meaningless external acoustical noise, at various sound pressure level values, on participants during a mental task. That is, the authors focused on the psychological impression of `annoyance' caused by noise, and `performance' indicated by factors such as percentage of correct answers and reaction time. More specifically, the authors discussed how these two items depend on the sound pressure level value of noise, and how they change due to meaningful or meaningless noise. Moreover, the difference between subjective feelings of `fatigue' before and after the task, both with and without noise was considered. Furthermore, an investigation was made into how the above items change in the case of aural or visual task presentations. The task was the probe digit, which is a short-term memory task. As a result, the importance of reducing meaningful external noise at low sound pressure level values was shown.     

基于声压-质点速度声强探头的材料吸声系数的测量

通过由一个声压换能器和一个质点速度换能器所构成的传感器(p-u声强探头)同时测量材料表面附近的声压和质点振动速度,可直接得到其声学阻抗,进而得到材料的反射因子、吸声系数。本文利用一个p-u探头声强测量系统,在半消声室内测量了三聚氰胺泡沫的吸声系数,分析了声源高度和入射角度、材料样本尺寸和厚度对吸声系数测量的影响,并和阻抗管中测量得到的法向吸声系数进行了对比。最后分析了声阻抗率的幅值和相位误差对吸声系数的影响,推导了它们的误差传递公式。     

Vortex sound under the influence of a piecewise porous material on an infinite rigid plane

The vortex dynamics and the sound generation by an inviscid vortex in the presence of a finite length porous material on an otherwise rigid plane are studied numerically in the present study in an attempt to understand the sound generation near the surface of a wall lining in a lined duct. The combined effects of the effective fluid density and flow resistance inside the porous material, and the length and thickness of the porous material on the sound generation process are examined in detail. Results obtained demonstrate the sound pressure is longitudinal dipole and show how seriously the above-mentioned parameters are affecting the vortex sound pressure under the influence of the porous material.     

Evaluation of the vibrational modes of the human skull as it relates to bone-conducted sound

Analytic and numerical models are used to study bone-conducted sound and how it relates to the vibrational modes of the human skull. The analytic model is based on the solution to the acoustic and elastic wave equations and the constraining boundary conditions for a fluid-filled elastic sphere. Both models predict that most of the acoustic energy of bone-conducted sound exists in the form of surface wave vibrations at the interface between two acoustic media rather than in the bone or cranial chamber. These surface waves have phase speeds much slower than the bulk sound speed for bone. The analytic model, based on spherical elastic shells, predicts a phase speed of 775 m/s and the first resonance frequency at 1500 Hz while the numerical solution yields approximate phase speeds of 450 m/s and provides a visual display of the surface waves and diffraction effects.     

Active traveling wave in the cochlea

A sound stimulus entering the inner ear excites a deformation of the basilar membrane which travels along the cochlea towards the apex. It is well established that this wavelike disturbance is amplified by an active system. Recently, it has been proposed that the active system consists of a set of self-tuned critical oscillators which automatically operate at an oscillatory instability. Here, we show how the concepts of a traveling wave and of self-tuned critical oscillators can be combined to describe the nonlinear wave in the cochlea.     

流形学习在运动声源声特征提取方面的研究*

运动声源因声信号时变性、叠加性和空时耦合性强,声数据呈现高维、非线性等特点,使得关键声特征提取困难,声特征提取方法复杂度高、数值计算量大、有效性差。因此,如何有效提取声特征并降低提取方法复杂度成为目前多源声场声源精准识别需迫切解决的关键科学问题。由此,该文提出短时傅里叶变换(STFT)和局部线性嵌入算法(LLE)联合的STFT-LLE流形学习声特征提取方法,并将此方法应用于运动声特征提取,且通过仿真实验测试对其进行了验证。该方法为运动声目标的分类识别提供了技术支撑。     

Sound field separating on arbitrary surfaces enclosing a sound scatterer based on combined integral equations

To eliminate the limitations of the conventional sound field separation methods which are only applicable to regular surfaces, a sound field separation method based on combined integral equations is proposed to separate sound fields directly in the spatial domain. In virtue of the Helmholtz integral equations for the incident and scattering fields outside a sound scatterer, combined integral equations are derived for sound field separation, which build the quantitative relationship between the sound fields on two arbitrary separation surfaces enclosing the sound scatterer. Through boundary element discretization of the two surfaces, corresponding systems of linear equations are obtained for practical application. Numerical simulations are performed for sound field separation on different shaped surfaces. The influences induced by the aspect ratio of the separation surfaces and the signal noise in the measurement data are also investigated. The separated incident and scattering sound fields agree well with the original corresponding fields described by analytical expressions, which validates the effectiveness and accuracy of the combined integral equations based separation method.     

Least squares approach in wavenumber domain for sound field recording and reproduction using multiple parallel linear arrays

A novel signal processing method is proposed for sound field recording and reproduction using multiple parallel linear microphone and loudspeaker arrays. In sound field recording and reproduction, the problem is how to calculate the transfer filters that transform the signals recorded by microphones into the driving signals of the loudspeakers. The proposed method is based on the spatial Fourier transform in the horizontal angle combined with the least squares (LS) approach in the elevation angle. In the proposed method, the signals recorded by each linear microphone array and those that drive each loudspeaker array are decomposed into the wavenumber domain by the spatial Fourier transform in the horizontal direction. The transfer filters are then calculated by the LS approach in the wavenumber domain. As a result, the size of the matrix of each transfer function in the wavenumber domain is much smaller than that of the conventional LS approach in the temporal frequency domain (LSTF), and well-conditioned stable transfer filters can be obtained with low computational cost without regularization. Computer simulation results show that the proposed method reconstructed a sound field around the control points as accurately as the conventional LSTF.     

双驱动电动换能器电磁场和声-结构耦合场分析

电动换能器的设计涉及电磁场和声-结构耦合问题,本文利用COMSOL多物理场分析软件提供的该两种分析模块进行组合,以电磁理论为基础推导出了适合COMSOL数值计算的公式,把两种耦合场的分析结合起来,利用电磁场分析过程计算所需要变量,代入声-结构耦合场进行分析,得到声场分布情况。文章也大致介绍了COMSOL的有限元建模和该两种模块的使用方法。本文对电动换能器结构如何优化不做讨论。     

Three-dimensional acoustic sound field reproduction based on hybrid combination of multiple parametric loudspeakers and electrodynamic subwoofer

Auditory Mixed Reality (MR) systems that reproduce Three-Dimensional (3-D) acoustic sound fields have recently become a research focus because the combination of visual and auditory MR systems can achieve a greater sense of presence than conventional visual MR systems. General auditory MR systems usually use a headphone-based system with a Head-Related Transfer Function (HRTF), which is a major system for reproducing 3-D acoustic sound fields. However, the localization accuracy of sound images with a HRTF depends on the individual. On the other hand, we have already proposed a system for reproducing a 3-D acoustic sound field with parametric loudspeakers instead of headphones. The 3-D acoustic sound field reproduced by this system has achieved a highly accurate localization of sound images. However, one problem is that it is difficult to reproduce lower frequency sounds using parametric loudspeakers, which causes a poorer sound quality. We tried to accomplish a greater sense of presence for 3-D acoustic sound fields based on a hybrid combination of an electrodynamic subwoofer and the parametric loudspeakers by improving the sound quality. Sound images were formed at the target location using the parametric loudspeakers, and a lower frequency sound was compensated for by using the electrodynamic subwoofer. Subjective evaluation experiments were conducted to verify the effectiveness of the proposed system. We confirmed the improved sound quality while maintaining a higher accuracy of sound image localization by using the proposed system. We also confirmed the optimum parameters of the proposed system to achieve a greater sense of presence.     

音乐厅音质设计进展述评

本文对近年来音乐厅音质设计中若干问题的进展作一述评。（1）在已建立的众多独立音质参量基础上，如何作出大厅综合评价，就需要考虑到它们的互动性和贡献权，方法学将成为关键。（2）空间感已确认由声源视在展宽度ASW和听者环绕感LEV组成，对于影响两者的诸多复杂因素有了较深入研究，这声场中的细节又将如何与大厅设计相联系亦备受关注。（3）听众及座椅吸声这个老问题有了新的研究成果，对于空、满场的声学关系已积累了更多资料，使大厅音质的估算更为精确可靠。（4）常说扩散对大厅音质很重要，但其主观效应仍然处于玄虚状态，一些新的主观试听实验结果还不足以说明问题。     

Perception of urban park soundscape

A number of studies have been initiated to explore how to improve the soundscape quality in urban parks. However, good soundscape quality in parks cannot be provided without a thorough understanding of the complex relationships among sound, environment, and individuals. As acoustic comfort is considered to be an important outcome of soundscape quality, this study investigates the relative impacts of the factors influencing acoustic comfort evaluation by formulating a multivariate ordered logit model. This study also explores the inter-relationships among acoustic comfort evaluation, acceptability of the environment, and preference to stay in a park using a path model. A total of 595 valid responses were obtained from interview surveys administered in four parks in Hong Kong while objective sound measurements were carried out at the survey spots concurrently. The findings unveil that acoustic comfort evaluation, besides visual comfort evaluation of landscape, also plays an important role on users' acceptability of the urban park environment. Compared with all the studied acoustic related factors, acoustic comfort evaluation serves as a better proxy for park users' preference to stay in urban parks. Hearing the breeze will significantly increase the likelihood of individuals in giving high acoustic comfort evaluation. Conversely, hearing the sounds from heavy vehicles or sounds from bikes will significantly reduce the likelihood in giving a high acoustic evaluation.     

VIRTUAL REALITY OF SOUND GENERATED FROM VIBRATING STRUCTURES

The advancement of virtual reality (VR) technology in cyberspace is amazing, but its development is mainly concentrated on the visual part. In this paper, the development of VR technology to produce sound based on the exact physics is studied. Our main concern is on the sound generated from vibrating structures. This may be useful, for example, in apprehending sound field characteristics of an aircraft cabin in design stage.To calculate sound pressure from curved surface of a structure, a new integration scheme is developed in boundary element method. Several example problems are solved to confirm our integration scheme. The pressure distributions on a uniformly driven sphere and cylinders are computed and compared with analytic solutions, and radiation efficiency of a vibrating plate under one-dimensional flow is also calculated. Also, to realize sound through computer simulation, two concepts, “structure-oriented analysis” and “human-oriented analysis”, are proposed. Using these concepts, virtual sound field of an aircraft cabin is created.     

Perception and annoyance due to wind turbine noise--a dose-response relationship

Installed global wind power increased by 26% during 2003, with U.S and Europe accounting for 90% of the cumulative capacity. Little is known about wind turbines' impact on people living in their vicinity. The aims of this study were to evaluate the prevalence of annoyance due to wind turbine noise and to study dose-response relationships. Interrelationships between noise annoyance and sound characteristics, as well as the influence of subjective variables such as attitude and noise sensitivity, were also assessed. A cross-sectional study was performed in Sweden in 2000. Responses were obtained through questionnaires (n = 351; response rate 68.4%), and doses were calculated as A-weighted sound pressure levels for each respondent. A statistically significant dose-response relationship was found, showing higher proportion of people reporting perception and annoyance than expected from the present dose-response relationships for transportation noise. The unexpected high proportion of annoyance could be due to visual interference, influencing noise annoyance, as well as the presence of intrusive sound characteristics. The respondents' attitude to the visual impact of wind turbines on the landscape scenery was found to influence noise annoyance.