Acoustic Experts Research Articles

Determination of reverberation time in large educational auditoriums

According to the current regulation, acoustic comfort in educational buildings in Lithuania is ensured by applying sound insulation of structures and limiting excessive room reverberation. The maximum reverberation time values described in the document depend on the building's acoustic comfort class, room volume and frequency range. In order to determine the design values of the reverberation time for larger auditoriums, there is a need for consultations with an acoustic expert. This paper presents some typical examples of reverberation time measurements in new, old and modernized large lecture halls. The measurement results indicate good practice in the design and installation of new auditorium, as well as the nature and importance of acoustic problems in old and modernized ones. The analysis of the measurement results allows us to assume that the success of the project's acoustic quality often depends on the designer's ability to properly assess the design indicators and the properties of applied materials.

Insights from the "Acoustics Workshop in Educational Buildings" by Turkish Acoustical Society

This paper focuses on "Acoustics Workshop in Educational Buildings" organized by the Turkish Acoustical Society as part of International Noise Awareness Day 2023 Activities. The workshop brought together 34 participants, including designers, acoustic experts, teachers, and health and occupational safety professionals. Through interdisciplinary discussions, participants identified and prioritized acoustic problems, expectations and requirements for educational buildings, focusing on improving the quality of education. The workshop unfolded in two stages: firstly, participants were grouped by profession to identify primary acoustic challenges. Subsequently, multi-disciplinary teams collaboratively developed mitigation strategies to address these challenges. The results revealed profession-specific insights into main acoustic issues and proposed actionable solutions. This paper specifically provides insights into the use of qualitative content analysis to have a deeper understanding of different professions, people's experiences, behavior and priorities in relation to acoustics in school.

Construction site environmental pollution management - initiatives, innovation and research

The management of pollution, and in particular of the impact of noise and vibrations, is very important for construction activities, even more so when it comes to urban construction sites. Indeed, some operations have very significant emissive potential and it is appropriate, for the proper conduct of the activities, to adopt a certain strategy in order to control the impacts and thus ensure good acceptance of the construction by the neighborhood. Environmental monitoring is the key to achieving this dual objective: prevent pollution and communicate. This paper presents our innovative approach to localize, identify and report noise pollution on construction sites for efficient noise mitigation. More precisely, usage of acoustic high resolution beamforming is discussed to both identify predominant sources and estimate reliably their contribution to overall noise pollution captured at a given reference point by à Class I metrological device. By combining the easy-to-deploy ATD directional acoustic sensor with its 10cm aperture microphone array, with video recording for event confirmation and labelling on the highly responsive Cadence interface, we show how we can solve complex use cases for a wide range of users, from site managers to acoustic experts.

Towards developing a model of adaptive acoustic comfort in the built environment: A thematic analysis from an expert focus group

The adaptive capacities of building occupants have so far been primarily investigated in relation to the thermal climate through the adaptive thermal comfort model. However, the concept of adaptation extends beyond thermal conditions and is relevant to other sensory modalities, such as acoustics. This is significant for both human health and well-being, as well as environmental considerations. The latter aspect is linked to potential variations in acoustic sensitivities between naturally ventilated and mechanically ventilated buildings, which, if identified and acknowledged, could lead to a greater applicability of passive ventilation strategies through tailored acoustic criteria. Drawing from thematic analysis of discussions held in a focus group comprising 8 experts in acoustics, soundscape, and adaptive thermal comfort, this study aims to 1) delineate the underlying assumptions of acoustic adaptation in built environments, and 2) establish a research agenda towards developing a framework for adaptive acoustic comfort. The identified themes include: the definition of adaptive acoustic comfort, potentially contributing acoustic and non-acoustic factors, differences and similarities with the adaptive thermal comfort model, and the methodology for collecting data. In terms of results, 1) adaptive acoustic comfort would be based on potential modifying effects of recent past acoustic exposure and other environmental factors (including multi-domain effects), contextual, and personal factors on people's acoustic expectations and preferences. 2) To test this concept, the very first step will have to be the construction of a comprehensive global acoustic comfort database.

Ten questions concerning Architectural Acoustics

Building and room acoustics are relatively modern architectural and engineering disciplines. Nevertheless, acoustics was also a concern for buildings in the past, e.g., in theatres in ancient Greece and in Roman times. Nowadays, we spend 80–90 % of our time indoors, and sound impacts our communication and actions in an environment to a great extent. Therefore, acoustic aspects should be considered appropriately in the Environmental Quality and Global Comfort context as part of the overall aspects of building physics, although other factors (e.g., thermal, air quality, etc.) are conventionally considered more “mainstream”. The ten questions considered in this paper range from the basic definitions underlying the differences between building and room acoustics, to more applied topics about how to measure, simulate and use acoustic data in the design of the built environment. Significant research activities have been conducted by acoustic experts on different aspects related to the measurements of physical properties, perceptual aspects and technological development in both the physical and virtual dimensions, thereby paving the way towards a more inclusive and healthier acoustic environment. Apart from illustrating the current state of the art, the answers to these questions point out the still existing gaps in the field and future challenges, thereby highlighting the new competencies required to support the design of the acoustic environment, focusing on the physical, physiological, and psychological needs of the users.

Automated echolocation classifiers vary in accuracy for northeastern U.S. bat species.

Acoustic surveys of bat echolocation calls are an important management tool for determining presence and probable absence of threatened and endangered bat species. In the northeastern United States, software programs such as Bat Call Identification (BCID), Kaleidoscope Pro (KPro), and Sonobat can automatically classify ultrasonic detector sound files, yet the programs' accuracy in correctly classifying calls to species has not been independently assessed. We used 1,500 full-spectrum reference calls with known identities for nine northeastern United States bat species to test the accuracy of these programs using calculations of Positive Predictive Value (PPV), Negative Predictive Value (NPV), Sensitivity (SN), Specificity (SP), Overall Accuracy, and No Information Rate. We found that BCID performed less accurately than other programs, likely because it only operates on zero-crossing data and may be less accurate for recordings converted from full-spectrum to zero-crossing. NPV and SP values were high across all species categories for SonoBat and KPro, indicating these programs' success at avoiding false positives. However, PPV and SN values were relatively low, particularly for individual Myotis species, indicating these programs are prone to false negatives. SonoBat and KPro performed better when distinguishing Myotis species from non-Myotis species. We expect less accuracy from these programs for acoustic recordings collected under normal working conditions, and caution that a bat acoustic expert should verify automatically classified files when making species-specific regulatory or conservation decisions.

Deep Learning-Based Design Method for Acoustic Metasurface Dual-Feature Fusion.

Existing research in metasurface design was based on trial-and-error high-intensity iterations and requires deep acoustic expertise from the researcher, which severely hampered the development of the metasurface field. Using deep learning enabled the fast and accurate design of hypersurfaces. Based on this, in this paper, an integrated learning approach was first utilized to construct a model of the forward mapping relationship between the hypersurface physical structure parameters and the acoustic field, which was intended to be used for data enhancement. Then a dual-feature fusion model (DFCNN) based on a convolutional neural network was proposed, in which the first feature was the high-dimensional nonlinear features extracted using a data-driven approach, and the second feature was the physical feature information of the acoustic field mined using the model. A convolutional neural network was used for feature fusion. A genetic algorithm was used for network parameter optimization. Finally, generalization ability verification was performed to prove the validity of the network model. The results showed that 90% of the integrated learning models had an error of less than 3 dB between the real and predicted sound field data, and 93% of the DFCNN models could achieve an error of less than 5 dB in the local sound field intensity.

Development of the Albanian translation of the Perceived Affective Qualities in the ISO/TS 12913-2 soundscape standard

The Perceived Affective Qualities (PAQs) outlined in the ISO/TS 12913-2:2018 standard have been translated into many languages and are referred to as a global standard to evaluate the acoustic environment in various contexts. There is a growing legislative framework in Albania that addresses noise pollution through Law No. 9774 and Guideline No.8. The aim of this study, which recognizes the increasing trends in acoustic research in Albania, and acknowledges the gap regarding soundscape descriptors has been to develop equivalent versions of the soundscape descriptors defined in ISO/TS 12913-2:2018 by translating the PAQs into the Albanian Language through a model fitting approach. This study, which has followed the Soundscape Attributes Translation Project (SATP) guidelines, has employed a mixed method, that is, both a qualitative investigation and a quantitative evaluation based on specific criteria built upon previous work, have been conducted. In the first phase (1a), eight linguistic experts independently translated eight affective attributes, which were later verified in the second phase (1b) by acoustic experts. After three potential translations had been generated for each of the eight PAQs, a quantitative approach, namely phase (1c), which had been proposed in previous SATP studies, was employed. Thirty-two native Albanian individuals, all of whom were proficient in English, evaluated the translated candidate terms in an online questionnaire, considering such criteria as their Appropriateness, Understandability, Clarity, Antipodal Antonymity, Orthogonal Unbiasedness, Connotativeness, Non-connotativeness, and Implicative Balance. The collected data were then subjected to a series of Kruskall Wallis tests with Bonferroni corrections to determine the final translation for each PAQ. In conclusion, eight Albanian attribute translations have been defined. Despite some limitations, our findings are promising and suggest that the selected attributes are validated inputs to the next steps of the research which involve listening experiments (SATP phase 2).

BIM-based sound insulation performance evaluation of interior walls

As a general contractor, acoustical design confirmation of a project at construction stage is rather limited especially if it is large-scale. Among others, many interior walls of the building projects are found to be improperly designed in terms of sound insulation in that chances are hardly given for the most projects to be intervened by an acoustic expert at their design stage. In many cases, they turn out to be either underperformed or overperformed. This study developed a tool for holistically evaluating sound insulation design of interior walls across the building areas. It was designed on the basis of BIM modeling to be fast-tracked in supporting either the architects or general contractors for a quick and broad design review. Mapping of the information of room use and wall types with their predicted or measured sound insulation data on to a BIM model is set out to compare to the design criteria according to room use and adjacency. The results are simulated on both 2-D and 3-D BIM models, visually presenting the sound insulation performance. A report is instantly generated on performance qualification with the information of wall types, surface areas, etc. It also suggests alternative wall types as necessary.

Automatic Robust Crackle Detection and Localization Approach Using AR-Based Spectral Estimation and Support Vector Machine

Auscultation primarily relies upon the acoustic expertise of individual doctors in identifying, through the use of a stethoscope, the presence of abnormal sounds such as crackles because the recognition of these sound patterns has critical importance in the context of early detection and diagnosis of respiratory pathologies. In this paper, we propose a novel method combining autoregressive (AR)-based spectral features and a support vector machine (SVM) classifier to detect the presence of crackle events and their temporal location within the input signal. A preprocessing stage is performed to discard information out of the band of interest and define the segments for short-time signal analysis. The AR parameters are estimated for each segment to be classified by means of support vector machine (SVM) classifier into crackles and normal lung sounds using a set of synthetic crackle waveforms that have been modeled to train the classifier. A dataset composed of simulated and real coarse and fine crackles sound signals was created with several signal-to-noise (SNR) ratios to evaluate the robustness of the proposed method. Each simulated and real signal was mixed with noise that shows the same spectral energy distribution as typically found in breath noise from a healthy subject. This study makes a significant contribution by achieving competitive results. The proposed method yields values ranging from 80% in the lowest signal-to-noise ratio scenario to a perfect 100% in the highest signal-to-noise ratio scenario. Notably, these results surpass those of other methods presented by a margin of at least 15%. The combination of an autoregressive (AR) model with a support vector machine (SVM) classifier offers an effective solution for detecting the presented events. This approach exhibits enhanced robustness against variations in the signal-to-noise ratio that the input signals may encounter.

The challenge and solutions to providing consistent masking sound levels in individual rooms

The propagation of sound in the built environment—impacted by size and geometry of a space, finishings, furnishings, and fit-outs—is exceptionally complex. It is for this reason that experts in acoustics need to consider all features of all spaces, despite the availability of prescriptive tools—e.g., categorization, acceptable-level and reverberation time [design] schemes—which are insufficient towards assuring any acoustical outcome. The use of a sound masking system is one acoustical solution that can be used to meet acoustical objectives, such as acoustical comfort and speech privacy, by reducing the variability in temporal, spectral, and spatial properties of sound within a space. The following investigation utilizes commissioning data of sound masking systems to underline the need for dedicated control zones for individual rooms. More specifically, the overall and one-third octave band levels of masking sound in rooms within the same control zone are compared against the project’s specifications (i.e., the target overall level and the reference masking spectrum). These results enforce opportunities to improve the performance of a sound masking system to realize more consistent perceptual (i.e., acoustical comfort and speech privacy) outcome.

Temel Bina Akustiği Uzmanlık Eğitimi Önkoşullarının İç Mimarlık Bölümü Üzerinden Sorgulanması

Building acoustic is an integral part of building physics in the field of architecture and interior design all over the world and plays a major role in providing auditory comfort conditions. According to the regulation published in the official gazette in Turkey in 2017, it has become obligatory to submit acoustic projects and reports at the license stage for buildings over certain number of floors and total area. These reports and projects can be prepared by acoustic experts who have the D1 Basic Building Acoustics Specialization Certificate. While it is sufficient to have a bachelor's degree in architecture and engineering to satisfy the prerequisites of participation in the D1 basic building acoustics certificate training, interior architecture undergraduates are entitled to attend this training only if they have a master's degree in acoustics. In this context, to examine this restriction, the qualifications expected from the people who will participate in the certificate training were determined by a preliminary survey study conducted with the instructors who are authorized to give basic acoustic training. Then, the level of the fulfillment level of the interior architecture graduates on determined qualifications was revealed via a questionnaire survey conducted with the heads of the interior architecture departments in Turkey who have a good knowledge of the interior architecture department outputs.

A Tutorial Review on Clinical Acoustic Markers in Speech Science.

The human voice changes with the progression of neurological disease and the onset of diseases that affect articulators, often decreasing the effectiveness of communication. These changes can be objectively measured using signal processing techniques that extract acoustic features. When measuring acoustic features, there are often several steps and assumptions that might be known to experts in acoustics and phonetics, but are less transparent for other disciplines (e.g., clinical medicine, speech pathology, engineering, and data science). This tutorial describes these signal processing techniques, explicitly outlines the underlying steps for accurate measurement, and discusses the implications of clinical acoustic markers. We establish a vocabulary using straightforward terms, provide visualizations to achieve common ground, and guide understanding for those outside the domains of acoustics and auditory signal processing. Where possible, we highlight the best practices for measuring clinical acoustic markers and suggest resources for obtaining and further understanding these measures.

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.

Preface

PROCEEDINGS OF THE AIVELA INTERNATIONAL CONFERENCE ON VIBRATION MEASUREMENTS BY LASER AND NONCONTACT TECHNIQUES ANCONA, 28- 29 JUNE 2021 Since October 1994 the AIVELA Conference on Vibration Measurements by Laser Techniques established itself as the international forum where research ideas and technological innovation on Laser Vibrometry were presented and exchanged. Ancona, an ancient and fascinating Italian town situated on the Adriatic coast, became the biennial destination of the international laser vibrometry community.The event was initially focused on Vibration Measurements by Laser Techniques and it immediately met large consensus among the International Research Community. In 2010 the Scientific Committee decided to widen the topics of the Conference by also including other noncontact techniques and the name of the event was changed to International Conference on Vibration Measurements by Laser and Noncontact Techniques. The Conference aims at creating an active and stimulating forum where current research results and technical advances can be exchanged and the development of new systems for laboratory use, field testing and industrial application can be promoted. For this reason, experts in vibration and acoustics, manufacturers and authorities in the field of optical and non- invasive instrumentation and industrial users of such measurement devices have come from all over the world to present their activities and innovative approaches to vibration measurements.List of Editor are available in this pdf.

Acoustic Study of Noise Generated by Arzew's Industrial Units in Limited Batteries

This study carried out concerns noise pollution from the Arzew industrial zone. Currently, noise is an integral part of our environment and represents a major current issue, due to its dangerous health effect. Due to the proximity between industrial sites and residential areas, which very often generates noise-related conflicts that require the intervention of an acoustic expert to resolve and protect the neighbourhood from noise exposure from the complexes in the Arzew industrial zone. We have dedicated our work to the assessment of noise emissions generated by several oil and gas plants located in the ARZEW industrial zone and to the verification of the application of laws relating to the limitation of noise levels emitted into the environment by the various facilities. We focused our study on noise measurements in the periphery of the plants, known as the "property limit", also known as the "battery limit".

The soundscape in cultural heritage

Soundscape analysis started to be a research field in the late sixties and received significant attention by researchers in the last twenty years. Experts in community noise and environmental acoustics and, more recently, policy makers and practitioners show interest for soundscapes, due to its multidisciplinary approach focusing on how people actually experience their acoustic environments in different indoor and outdoor environments. In 2014 the International Organization for Standardization (ISO) officially defined Soundscape as “acoustic environment as perceived or experienced and/or understood by people, in context”. The peculiarity of the Soundscape approach is that it firstly relies upon human perception and then turns to physical assessment. The study of the soundscape related to cultural heritage is a subject not yet very widespread and deeply investigated by researchers and designers. In this paper, after an introduction about the general soundscape concept and approach, its connection with quiet areas is addressed. Moreover, existing methodologies to deal with the soundscape of cultural heritage are reported, together with the recent trend of archiving sounds considered to be disappeared or lost in memory, to enhance them as the cultural heritage of our society.

13th International Conference on Vibration Measurements by Laser and Noncontact Techniques

PROCEEDINGS OF THE AIVELA INTERNATIONAL CONFERENCE ON VIBRATION MEASUREMENTS BY LASER AND NONCONTACT TECHNIQUES ANCONA, 20-22 JUNE 2018Since October 1994 the AIVELA Conference on Vibration Measurements by Laser Techniques established itself as the international forum where research ideas and technological innovation on Laser Vibrometry were presented and exchanged. Ancona, an ancient and fascinating Italian town situated on the Adriatic coast, became the biennial destination of the international laser vibrometry community.The event was initially focused on Vibration Measurements by Laser Techniques and it immediately met large consensus among the International Research Community. In 2010 the Scientific Committee decided to widen the topics of the Conference by also including other noncontact techniques and the name of the event was changed to International Conference on Vibration Measurements by Laser and Noncontact Techniques.The Conference aims at creating an active and stimulating forum where current research results and technical advances can be exchanged and the development of new systems for laboratory use, field testing and industrial application can be promoted. For this reason, experts in vibration and acoustics, manufacturers and authorities in the field of optical and non- invasive instrumentation and industrial users of such measurement devices have come from all over the world to present their activities and innovative approaches to vibration measurements.

A measuring instrument for the auditory perception of rooms: The Room Acoustical Quality Inventory (RAQI).

With the Room Acoustical Quality Inventory (RAQI), a measuring instrument for the perceptual space of performance venues for music and speech has been developed. First, a focus group with room acoustical experts determined relevant aspects of room acoustical impression in the form of a comprehensive list of 50 uni- and bipolar items in different categories. Then, n = 190 subjects rated their acoustical impression of 35 binaurally simulated rooms from 2 listening positions, with symphonic orchestra, solo trumpet, and dramatic speech as audio content. Subsequent explorative and confirmative factor analyses of the questionnaire data resulted in three possible solutions with four, six, and nine factors of room acoustical impression. The factor solutions, as well as the related RAQI items, were tested in terms of reliability, validity, and several types of measurement invariance, and were cross-validated by a follow-up experiment with a subsample of 46% of the original participants, which provided re-test reliabilities and stability coefficients for all RAQI constructs. The resulting psychometrically evaluated measurement instrument can be used for room quality assessment, acoustical planning, and the further development of room acoustical parameters in order to predict primary acoustical qualities of venues for music and speech.

Management at corporate level of noise exposure assessment and control for Petrobras refining

This article presents the work carried out as part of a project aiming to regulate the noise exposure of workers of PETROBRAS refining units. This is a corporate project carried out over a three years’ period (2012 to 2015) by the Supply business unit of the Brazilian company. The uniqueness of this project is due to its scale. Indeed, this encompassed twelve refineries located throughout Brazil. The corporate approach to deal with noise exposure risk leads to an overall data consolidation allowed by a standardized methodology. The methodology used is split into four phases. First, a long but necessary planning stage, then an exhaustive assessment of the current noise situation of production areas was carried out during the first twelve months of the project. This stage allowed the involvement of several important tools used to identify and rank noise exposure issues. This lead to noise maps of every industrial area and an acoustic database of equipment exceeding regulatory limits (sound power level and directivity). Third, every industrial area was modelled into noise prediction software compliant with ISO 9613-2 standard. Finally, acoustic damping solutions were designed and proportioned by size of equipment. This mixed approach of measurement and numerical simulation mobilized a dedicated ACOEM project team comprising of eight acoustic experts. Principal achievement of this project, concluded in 2015, is a clear vision of the noise control priorities allowed by standardized methodology on all refineries in a short time. This achievement leads to a coherent set of controls for the future investments to be done to mitigate noise exposure risks. In addition to highlighting the benefits of integrated Health Safety and Environment (HSE) management, this work provides an understanding on the use of virtual computing doses from propagating acoustic model.