The main goal of this study was to investigate how visual impairment affects speech intelligibility in noisy environments, comparing individuals with normal hearing and those with presbycusis using bilateral hearing aids. Participants underwent an audiovisual FraMatrix test under different visual acuity conditions. The study found a significant reduction in audiovisual intelligibility in noise as visual acuity worsened. These findings underscore the importance of addressing both hearing and vision impairments in clinical practice to enhance patient well-being and reduce social isolation
The reality of sound propagation outdoors is more complicated than simple geometrical spreading above a flat hard ground. Most common grounds, such as grass covered ground and layers of snow, are acoustically soft. This implies a complex reflection coefficient leading to a measured spectrum that is strongly influenced by the type of ground surface between source and receiver. Grounds may not be flat, leading to shadow zones or alternatively multiple reflections at the ground. Gradients of wind and temperature refract sound either upwards (upwind or in a temperature lapse) or downwards (downwind or in a temperature inversion), also leading to shadow zones or multiple reflections, respectively. Atmospheric turbulence causes fluctuations and scatters sound into acoustical shadow zones. Many of these features mutually interact and accurate predictions of sound transmission from source to receiver must somehow account for all of these phenomena simultaneously. Thus for example, ISO 9613 Part 2 in wide use today, attempts to account for all the phenomena empirically. In recent years the application of numerical techniques has led to significant advances. This plenary will review the various phenomena. Emphasis will be put on field measurements and simple physical interpretations. In a few cases, the predictions of ISO 9613 Part 2 will be compared with physical or numerical models
Updated regulations, improved noise reduction, and increased use of hearing protective devices (HPDs) may result in better hearing for noise-exposed workers. In a retrospective longitudinal (1980-2015) cohort study, we conducted a secondary analysis of a database of annual hearing tests from noise-exposed workers aged 20-55 years old. Sample size per cohort ranged from n=1386 to n=5165. No clinically-meaningful cohort differences in thresholds of 5 dB or greater were found for 20- or 30-year olds. For 45- and 55-year olds, later-born cohorts had better thresholds than earlier-born cohorts. Prevalence of hearing loss decreased for later-born cohorts for 30, 45, and 55-year olds. Twenty-year olds in later cohorts were more likely to use HPD than those in earlier cohorts. The lower prevalence of hearing loss and better thresholds in these noise-exposed workers may be due to increased HPD use, changes in workplace regulations, improved workplace noise control, or changed attitudes towards recreational noise exposure.
In this paper, the acoustic characteristics of the ancient Roman theatre of Cassino are discussed. The theatre was built during the Imperial Age and was abandoned and destroyed after the Barbaric invasions. The theatre has been rebuilt in recent years and it is currently used for summer events ad performance. To measure the acoustic characteristics of this ancient theatre, the authors used a spherical omnidirectional sound source placed on the stage and in the orchestra. The results show that nowadays the theatre has a short reverberation time equal to 0.6 seconds due to the lack of the stage wall, which has not been rebuilt. The weak sound strength justifies the use of electro-acoustic amplification systems which during the summer season, are adopted to improve the acoustic experience in this ancient theatre.
The attention by the scholars to the acoustics of ancient open-air theatres is increased considerably through the centuries and among the historical buildings survived to nowadays the acoustics of the Roman theatre of Verona has not been deeply investigated, yet. In this paper, the outcomes of the acoustic survey undertaken in the Roman theatre has been analysed in two different ways: by a standard methodology representing the graphs of the acoustic parameters, and by the creation of a video showing in real-time the impulse response (IR) and relative reflections occurred at the surfaces of the cavea. The latest technique has been realised by using a multichannel spherical microphone array, which calls back the MIMO approach that is capable to have complete spatial control of the sound propagation through space. The authors of this paper illustrate a brief history of the theatre, including the description of the construction elements that characterise this important historical building, and two distinct procedures to show the results obtained after the survey, highlighting the coplanarity of explanation by using the MIMO approach, as followed by the second methodology.
Exhaust noise must meet customer expectations, legislation targets, and cost reduction which call for design optimization of the exhaust systems in the design phase. Shape optimization of reactive mufflers using algorithms became as one of important solutions to improve the acoustic performance of compact mufflers used in a limited space.In this paper, a numerical assessment of single expansion-chamber muffler with extended tube under limited space is performed by the maximization of the sound transmission loss (STL) using the Transfer Matrix Method (TMM) and Finite Element Method (FEM). This shape optimization analysis is performed using novel schemes called Threshold Acceptance (TA) and Simulated Annealing (SA), a robust schemes used to search for the global optimum by imitating the metal’s heating process, an accuracy check on the mathematical model is performed. Also, for reliability check on the TA and SA methods, the STL’s maximization with respect to a one-tone noise is introduced, the best designs obtained by the two methods are compared and analyzed by Finite Element Method (FEM). The Transfer Matrix Method (TMM) is a modelling method based on the plane wave propagation model and the FEM solution used to analyze the STL of the shape optimized mufflers is based on the Acoustic Power method. A standard computational code COMSOL Multiphysics is used to analyze in 3D the sound attenuation of the muffler by the FEM method. The acoustical ability of the muffler obtained is than assessed by comparing the FEM solution with the analytical method. Results show that the best acoustical performance is obtained with TA optimizer and the maximal STL is precisely located at the desired targeted tone. Consequently, the optimal approach on the design of single expansion-chamber muffler with extended tube presented in this study provides quick and novel schemes for the shape optimization of muffler under limited space.
Experimental evidence suggests that crowdsourced online experiments, where suitable, may produce better data than in-lab studies. The absence of a reliable screening method for headphones and dichotic auditory context (perfect separation of the stereo channels) is one of the main reasons why online crowdsourcing is rarely possible for auditory studies. As the evidence demonstrates, the responses to the questions “Are you wearing headphones” and “Are the headphones stereo channels separated” are providing unreliable and even conflicting results. Here we show that the interference beating phenomenon can be used as a screening method for dichotic context with satisfactory accuracy. We collected data through an in-lab experiment to test the method’s performance against the reference (the truth), avoiding the uncontrolled biases of the online experiments, achieving Cohen’s Kappa of 0.79 (95% CI, [0.52, 1.06], p<0.001), yielding “Substantial agreement” when calculated over the whole sample, and Cohen’s Kappa of 1 (95% CI, [1, 1], p=0.001), yielding “Almost perfect agreement” when calculated only over the true dichotic cases. Also, we collected data by using the only other method found in the literature that attempts screening for headphones usage, to compare both methods over the same participants and auditory contexts. The usage of the new method is tested in a crowdsourced setting, involving over 2000 online participants. The in-lab and online results suggest that the method introduced in this study is suitable, and therefore, an enabler of auditory online crowdsourced studies.
In this paper the results of noise measurements generated by the operation of 200 kW mini wind turbine, carried out inside a home are reported. The number of wind turbines with a lower eclectic power increases significantly due to the necessary administrative simplification, and for the economy of the investment. This involves the installation of numerous wind turbines also near houses. One of the biggest impact problems is the noise pollution produced by the rotation of the blades. Acoustic measurements were performed in a home, with open windows, condition of maximum noise disturbance. When the wind tower is in operation, a noise level of about 45 dBA has been measured. This condition generates annoyance to the people living in the house. Furthermore, an assessment of the noise generated by the operation of a mini wind tower was carried out, applying the ISO 9613 standard; the theoretical sound pressure level underestimates the value measured.
This study addresses an assessment of some sound identification methods using circular microphone arrays for sources interior to the array circle. Various techniques are compared, including classical beamforming (CB), regularized inverse methods (Tikhonov regularization), L1- generalized inverse beamforming (L1-GIB), deconvolution methods CLEAN-PSF, CLEAN-SC, as well as more recent inverse methods using beamforming regularization (BFR). To highlight the advantages and disadvantages of these methods, several numerical and experimental application examples are discussed. When multiple sources are searched, the results show that the method of choice depends on the correlation, directivity and relative level of the sources.
An experimental investigation was conducted on the effect ‘butterfly acoustical skin’ (metallic version of the lepidopterans scale coverage) on the acoustic performances of two - bladed propeller (diameter of 1200 mm, airfoil sections of NACA 2415, rotating speed of 1780 rpm, Re ≈ 2 × 105) in a low – speed straight through a wind tunnel. Attention was initially directed to this problem by observation of the porous scales and porous scale coverage of lepidopterans as well as other studies indicating the noise suppression of flying lepidopterans by wing appendages. The property of the moth coverage allows these insects to overcome bat attacks at night. These appendages are very small (size: 30 – 200 µm) and have a various porous structures. I discuss both many different micro – and nanostructures of the porous scales, and many differences in details among various structures of the porous scale coverage of lepidonterans. I consider here only porous scales of butterflies Papilio nireus, Nieris rapae, Deelias nigrina, male Callophrys rubi, male Polyommatus daphnis, butterfly Papilio palinurus as well as porous scale coverage of cabbage moth, moth of Saturniidae family and moth of Noctuoidea family. The evolutionary history of lepidopterans and the properties of lepidopterans scale coverage are briefly discussed as well as different methods of reducing aero acoustic noise of aircrafts. The design of ‘butterfly acoustical skin’ with a hollow region imitates the cover hollow wing scale of the Papilio nireus butterfly. The design of ‘butterfly acoustical skin’ with a porous region imitates the cover hollow wing scale of the Pieris rapae butterfly, and from the cover hollow wing scale of the Delieas nigrina butterfly. Results indicate that the total sound pressure level of the rotating propeller with hollow skin is more than 2 dB lower with respect to the one with the smooth skin; and the total sound pressure level of the rotating propeller with the porous hollow skin is more than 4 dB lower with respect to the one with the smooth skin. The modification of acoustical effects on the rotating propeller with smooth ‘butterfly acoustical skin’ with a porous region was found to be to an acoustic absorption and to a dissipation of turbulent energy and to a reducing influence on noise generated. The same principles of the propeller noise reduction mechanism can explain by smooth ‘butterfly acoustical skin’ with a hollow region.
Natural sounds are integral elements of the environment that are frequently associated with parks and similar areas. They are, indisputably, inherent components of landscapes and their contents of and historical features, and particularly of their wildlife. Natural sounds constitute an indicator of the health of the wildlife habitat and the diverse ecosystems that comprise such areas. The present generation has an acknowledged obligation to conserve these resources for the benefit of those to come. In the process of planning to achieve the objectives of acoustic quality of the soundscape, the fundamental principle for determining the health of the environment, which forms part of the general planning of the parks, is the preservation of the soundscape at levels compatible with the characteristics of the park. When deficiencies are identified, action needs to be taken to restore the soundscape to its condition. The objective of this project is to analyse the existence of “non-natural” noises foreign to the environment and protect the Natural Soundscape from intrusive acoustic impacts. The study was carried out on the natural area of Anceu, located in the municipality of Pontecaldelas in the province of Pontevedra, Galicia (Spain).
Because of the COVID-19 situation, the Acoustics Week in Canada (AWC) originally planned for October 2020 in Sherbrooke (QC) has been postponed to October 2021. Nevertheless, and as a warm up, Sherbrooke''s organizing committee had been looking into setting up a little 1-day online celebration for October 2020. This report presents the highlights of AWC2020 One-Day Celebration that took place online on October 9, 2020.
The church of the Holy Family in Salerno (Italy) built in 1971 radically revolutionized the spatial structure of pre-conciliar church building design. The circular stepped geometry of the roof required a complex work with the employment of shipyard workers to come out with a unique geometry. However, such futuristic geometry also resulted in challenging conditions for its acoustics, as they emerged when the construction was completed. In this paper, the results of measurements of the spatial distribution of the acoustic characteristics in this large space are reported. The analysis of the acoustic parameter values confirms the poor acoustic conditions for speech and music listening. With the help of modelling, the authors have investigated possible solutions for the acoustic correction of this modern architecture. This paper reports the conclusions of such a study.
Aware of the very important role played by its members and in order to better serve them, CAA Board of Directors decided in 2019 to send a survey to all its current and past members to better understand how it is doing and how it could improve the service to its members. This article presents the questions sent out, the answers received and details for each relevant one a proposed plan of action.
