The acoustic climate of spaces located under overpasses in the context of adapting them for outdoor public events – a pilot case study

Due to the current shortage of traditional public space because of its privatization, commercialization, and securitization, there is an urgent need to reclaim areas affected by motorized traffic in the urbanized areas. On the other hand, the process of adapting them for new purposes should be carefully carried out, addressing several issues, among them environmental acoustics. This study is meant to contribute to our understanding of acoustic conditions of a general model of the bridge underspace. Therefore, the aim of the research was to examine the existing acoustic climate by measuring noise levels and comparing them with equivalent acceptable noise levels for the expected type of space development and Noise Rating curves. In this research, a pilot case study approach was used, as measurements were taken for a chosen space located under an elevated road that represents certain criteria set by the researchers. The results allowed us to: (1) verify the relationship between the geometry of the bridge underspace and the noise levels, (2) assess the initial acoustic conditions in terms of possibilities of acoustic adaptation of the examined space for outdoor public events, and (3) formulate hypotheses and preliminary assumptions for the planned further and broader studies of the issues raised in this article. The presented results and their analysis show that it is possible to bring the acoustic conditions in the studied space to the state required for public or cultural meeting spaces. In comparison with earlier findings, the research undertaken appears to be pioneering and the results can be used as valuable input for further research on this topic.

Noncontinuous noise calculated by room response function determined by experimental data

Purpose: Experimental determination of the response room function and its use to estimate the acoustic conditions in rooms with noncontinuous noise sources.Methodology/approach: The detailed parameter calculation of noncontinuous sound fields using the response room function, which is the room response to pulse excitation. The response function can be calculated by analytical or numerical methods and by experimental measurements in production conditions the energy attenuation when a constant noise source is switched off.Findings: Noncontinuous noise has a negative impact on health. The effective noise reduction is determined by the complete and accurate analysis of its energy parameters. The noncontinuous noise estimation based on equivalent levels does not meet the requirements, especially when pulsed noise sources are active. The experimental technique is proposed for the response function calculation and its use in evaluating the noise conditions in rooms with noncontinuous noise sources.Practical implications: The experimental determination of the response function to pulse excitation allows studying the acoustic processes in rooms for the formation of noise conditions when analytical methods cannot be used. The experimentally obtained response function makes it possible to solve problems of changing the noise conditions in rooms with noncontinuous noise sources.

The methods for the formation of optimal acoustic conditions for the transmission of speech content in small rooms

The subject of research in the article is the methodology for the examination of small-volume premises with a predominance of speech content. The aim of the work is to analyze all stages of acoustic expertise for meeting rooms, conference rooms, press centers, to determine the volume and sequence of the stages, taking into account the specific restrictions and conditions that arise in small rooms. All stages of acoustic expertise are considered in the work on examples of real premises of meeting rooms, conference halls, press centers. The sequence of stages of the examination, when it was carried out for premises of small volumes, did not undergo any changes, compared to the sequence that is used for spectator halls. The main distinctive feature of the first stage of acoustic examination in small rooms with a predominance of speech content is the analysis of the structures of the reverberation process in listening places in order to identify the drawbacks of the formation of a diffuse field, instead of checking the geometry of the wall and ceiling panel walls using geometric theory. A feature of the second stage is the development of recommendations for improving the sound-absorbing properties of enclosing surfaces and eliminating the effect of multiple re-reflections of sound energy between parallel surfaces through the use of partial replacement of surface geometry, work with suspended ceiling structures and the use of sound-absorbing curtains (to correct the properties of glass surfaces). The third and fourth stages of the examination remained unchanged.

An Analysis of Sound Event Detection under Acoustic Degradation Using Multi-Resolution Systems

The Sound Event Detection task aims to determine the temporal locations of acoustic events in audio clips. In recent years, the relevance of this field is rising due to the introduction of datasets such as Google AudioSet or DESED (Domestic Environment Sound Event Detection) and competitive evaluations like the DCASE Challenge (Detection and Classification of Acoustic Scenes and Events). In this paper, we analyze the performance of Sound Event Detection systems under diverse artificial acoustic conditions such as high- or low-pass filtering and clipping or dynamic range compression, as well as under an scenario of high overlap between events. For this purpose, the audio was obtained from the Evaluation subset of the DESED dataset, whereas the systems were trained in the context of the DCASE Challenge 2020 Task 4. Our systems are based upon the challenge baseline, which consists of a Convolutional-Recurrent Neural Network trained using the Mean Teacher method, and they employ a multiresolution approach which is able to improve the Sound Event Detection performance through the use of several resolutions during the extraction of Mel-spectrogram features. We provide insights on the benefits of this multiresolution approach in different acoustic settings, and compare the performance of the single-resolution systems in the aforementioned scenarios when using different resolutions. Furthermore, we complement the analysis of the performance in the high-overlap scenario by assessing the degree of overlap of each event category in sound event detection datasets.

Improving Building Acoustics

One of the most significant aspects which need to be analysed in the case of a building consists in finding that the sound level perceived by listeners is a proper one (Daniela-Roxana Tămaş-Gavrea et all., 2012). Their inconsistent spreading can develop problems in audition which can be solved only by putting in work a number of measures of acoustic rehabilitation. The evaluation of the acoustic quality of a building is a delicate issue, because of the complex system of the sound field contained in closed spaces and the sound features of the outlining surfaces. This paper presents a research on improving the acoustic conditions of a building which initially had a technical-administrative destination and was then converted into an office building (Stanca S.E., 2021). The measures of acoustic protection were recommended with a view to mitigate the noise level under admissible limits in the functional unit under consideration.

The effect of classroom acoustic conditions on literacy outcomes for children in primary school: A review

Literacy skills are essential for success in today’s society. However, classrooms often have suboptimal acoustic conditions for learning. The goal of this review was to synthesize research assessing the effect of different classroom acoustic conditions on children’s literacy. A comprehensive search of four online databases was conducted in August 2021. The search term was classroom AND (noise OR reverberation OR acoustics) AND (reading OR spelling OR writing OR literacy). Eighteen papers were deemed relevant for the review plus an additional seven from their references. The types of acoustic conditions that have been assessed, the types of measures used to assess literacy, and the effect of the acoustic conditions on children’s reading, writing, and spelling outcomes are discussed. Suggestions for the classroom acoustic conditions needed to ensure appropriate literacy development and areas for future research are also considered.

Underwater Target Signal Classification Using the Hybrid Routing Neural Network

In signal analysis and processing, underwater target recognition (UTR) is one of the most important technologies. Simply and quickly identify target types using conventional methods in underwater acoustic conditions is quite a challenging task. The problem can be conveniently handled by a deep learning network (DLN), which yields better classification results than conventional methods. In this paper, a novel deep learning method with a hybrid routing network is considered, which can abstract the features of time-domain signals. The used network comprises multiple routing structures and several options for the auxiliary branch, which promotes impressive effects as a result of exchanging the learned features of different branches. The experiment shows that the used network possesses more advantages in the underwater signal classification task.

Impact of Background Music on the Performance of Laparoscopy Teams

BACKGROUND: Music and noise have different impacts on individuals in the operating room. Their effects on the performance of surgical teams in simulated environments are not well documented. We investigated if laparoscopic teams operating under favorable acoustic conditions would perform better than under noisy conditions.METHODS: We recruited 114 surgical residents and built 57 two-person teams. Each team was required to perform two laparoscopic tasks (object transportation and collaborative suturing) on a simulation training box under musical, neutral, and noisy acoustic conditions. Data were extracted from video recordings of each performance for analysis. Task performance was measured by the duration of time to complete a task and the total number of errors, and objective performance scores. The measures were compared over the three acoustic conditions.RESULTS: A musical environment elicited higher performance scores than a noisy environment for both the object transportation (performance score: 66.3 ± 8.6 vs. 57.6 ± 11.2; p < 0.001) and collaborative suturing tasks (78.6 ± 5.4 vs. 67.2 ± 11.1; p < 0.001). Task times in the musical and noisy environments was subtracted to produce a musical-noisy difference time. Pearson correlation coefficient analysis showed a significant negative relationship between the team experience score and the musical-noisy difference time on the object transportation (r = -0.246, p = 0.046) and collaborative suturing tasks (r = -0.248, p = 0.044). CONCLUSIONS: As to individuals, music enhances the performance of a laparoscopy team while noise worsens performance. The negative correlation between team experience and musical-noisy difference time suggests that laparoscopy teams composed of experienced surgeons are less likely affected by an acoustic distraction than novice teams. Team resistance to acoustic distraction may lead to a new way for assessing team skills.

Indicative Assessment of Classroom Acoustics in Schools Built in Reinforced Concrete Technology on The Example of a School Building in Zabrze

In view of room acoustics in schools, not only noise level is extremely important, but also the reverberation conditions in a given room. Such conditions affect the intelligibility of speech, which determines the acquisition level of knowledge conveyed by the teacher. The article presents problems of school classroom acoustics for a building made in reinforced concrete technology on the example of a school building in Zabrze. For the research, we selected one of schools established in 1970s as a memorial of the Millennium Jubilee of the Republic of Poland. The obtained results of the reverberation time indicate poor acoustic conditions, which, regrettably, is quite common in Polish schools. For low frequencies, the reverberation time of a classroom for teaching mathematics was over 2 seconds, and for medium frequencies it was almost 2 seconds. The article presents the acoustics of the studied classrooms without proposals of acoustic adaptation.

Environmental Acoustic Comfort in the Built Environment

The acoustic quality of classrooms has a strong influence on the teaching and learning process. This interference assessed using the impulsive technique to measure the rate of speech transmission (STI), reverberation time (RT) and sound definition (D50). These are the most relevant acoustic descriptors in the assessment of classrooms, where verbal exposure is the means of communication between teachers and students. The evaluation took place in two buildings of the Federal University of Paraná (UFPR), built in the 1960s and another in 2016. The measured values ​​of STI, provided in the classrooms' actual acoustic conditions, were used as an adjustment parameter for simulations made with the software ODEON. After carrying out the measurements and simulations, the dimensioning of improvements was possible. The acoustic simulations presented suggestions to qualify the quality of the classrooms' acoustic comfort, ensuring that teaching and learning to do not suffer losses due to the physical structure of the classrooms. The measured values ​​of STI, RT and D50 show that, in the old building, except for a single classroom that preserves the original ceiling that had a high sound absorption coefficient, it has reasonable values, below the ideal for classrooms, according to the IEC 60268-16 (2011) standard. The investigation showed that the rooms with a roof replaced by a PVC covering had a sharp drop in acoustic quality. The newest building has classrooms with proper acoustic comfort conditions.