Integration of soundscape assessment and design principles into international standards and guidelines for learning environment acoustics

The main problem in the measurement of airborne sound insulation is the measurement of the sound power radiated by the barrier, in practice performed by measuring the sound pressure level and the acoustic absorption in the receiving room. Large variations of the sound pressure level in a reverberation room indicate the presence of dominating strong standing waves, so that it becomes necessary to install diffusing elements. In ISO 10140, the limits have been defined in which the reverberation time at frequencies at and above 100 Hz should be included. Sometimes, however, in the case of rooms with a large volume, obtaining the required parameters is difficult and sometimes even impossible. It should then be checked whether the measured sound insulation depends on the reverberation time. The paper presents the results of sound insulation measurements at various reverberation time lengths in subsequent stages of diffusing elements installation in the receiving room. An analysis of diffusing materials amount and arrangement influence on the uniformity of the sound pressure level distribution and reverberation time in the room as well as the value of the measured sound insulation was carried out. Uncertainty of sound insulation measurement with partial uncertainties was adopted as a criterion supporting the assessment of the obtained results.

Evaluation of the acoustic performance of classrooms in public schools

Acoustics and new learning environment – A case study

Effect of outdoor noise and façade sound insulation on indoor acoustic environment of Italian schools

In building acoustics, two different problems usually arise. There is a need to comply with established sound insulation parameters, but there are also legislative conditions concerning reverberation time. It is therefore necessary to acoustically insulate and condition the enclosures. When designing the acoustic treatment of buildings, sound insulation is always considered before acoustic conditioning. There are multiple solutions for sound insulation; one of them consists of a base wall reinforced with a plasterboard lining. The sound insulation improvement provided by these solutions will depend on the type of base wall used. A common solution for acoustic conditioning is the use of perforated plate lining systems with a plenum filled with sound absorbing material. This work presents a solution for simultaneous sound insulation and conditioning improvement, reducing the installation costs. Materials that provide the acoustic conditioning features were analyzed to validate their use in the complete solution, performing airflow resistance tests. The complete solution was also evaluated on a laboratory scale by conducting tests in a reverberation chamber and in a transmission chamber for small samples. Finally, the effectiveness of the presented solution was assessed with in-situ tests in a radio studio.

An investigation of acoustical environments in the elderly care facilities

What's missing in sex chromosome aneuploidies? Representation and inclusion

Two new applications have been developed for a hand-held analyzer: Building acoustics and sound intensity/sound power. The building acoustics application is designed for measurements of airborne and impact sound insulation and reverberation time. The sound intensity application is used for sound power measurements, noise source location, noise mapping, and building acoustics. Both applications we used with complete systems consisting of all the necessary parts to simplify the measurement task and provide the user with all results immediately at the measurement site. There is no need for postprocessing. The measurements can be done according to a wide selection of international and national standards. The paper will describe the use of both applications in solving a problem in building acoustics. The building acoustic application will be used to detect a problem with poor sound insulation of a wall. Then, the intensity technique is used to determine the cause of the problem. Both applications use a built-in noise generator in the hand-held analyser with wireless transmission to an amplifier/loudspeaker. The paper will focus on the various design features that have been incorporated to ensure easy, secure, and flexible use.

BackgroundGrey literature is an important source of information for large-scale review syntheses. However, there are many characteristics of grey literature that make it difficult to search systematically. Further, there is no ‘gold standard’ for rigorous systematic grey literature search methods and few resources on how to conduct this type of search. This paper describes systematic review search methods that were developed and applied to complete a case study systematic review of grey literature that examined guidelines for school-based breakfast programs in Canada.MethodsA grey literature search plan was developed to incorporate four different searching strategies: (1) grey literature databases, (2) customized Google search engines, (3) targeted websites, and (4) consultation with contact experts. These complementary strategies were used to minimize the risk of omitting relevant sources. Since abstracts are often unavailable in grey literature documents, items’ abstracts, executive summaries, or table of contents (whichever was available) were screened. Screening of publications’ full-text followed. Data were extracted on the organization, year published, who they were developed by, intended audience, goal/objectives of document, sources of evidence/resources cited, meals mentioned in the guidelines, and recommendations for program delivery.ResultsThe search strategies for identifying and screening publications for inclusion in the case study review was found to be manageable, comprehensive, and intuitive when applied in practice. The four search strategies of the grey literature search plan yielded 302 potentially relevant items for screening. Following the screening process, 15 publications that met all eligibility criteria remained and were included in the case study systematic review. The high-level findings of the case study systematic review are briefly described.ConclusionsThis article demonstrated a feasible and seemingly robust method for applying systematic search strategies to identify web-based resources in the grey literature. The search strategy we developed and tested is amenable to adaptation to identify other types of grey literature from other disciplines and answering a wide range of research questions. This method should be further adapted and tested in future research syntheses.Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-015-0125-0) contains supplementary material, which is available to authorized users.

This research is a case study developed to evaluate and compare the classroom acoustics of two different buildings from the Federal University of Paran, built in different times: Building CP (from the 1960s) and building JB (built in 2000). Acoustical parameters have been measured in eight classrooms of the CP building, and seven classrooms of the JB building: Sound pressure level, reverberation time, and sound insulation. The methodology employed followed standard procedures for acoustical evaluation of classrooms. Results showed that the classrooms of the CP building, from the 1960s, display satisfactory acoustical conditions, especially in their reverberation times. On the contrary, classrooms of the more recently built JB building yielded poor results with respect to reverberation times, either in empty classrooms, or in partially or even totally occupied classrooms, not meeting the values set by the standards. Thus, despite the evolution of the studies and research on room acoustics, older classrooms...

Objective and subjective evaluation of the acoustic comfort in classrooms

New studios for Croatian Radio-Television were planned with the starting user conditions. The background noise level must fulfill N15 or N20 criteria. Demanded reverberation time for a 400 m2 radio studio is Tr=0.6 s, for TV studios of the same area, Tr=0.7 s, and for the 1000 m2 TV studio, reverberation time is 1 s. Since all three studios with built-in control rooms were built in an urban area with excessive noise, it was necessary to obtain very good protection against noise, and at the same time, using the same elements, achieve the desired reverberation time. Special attention was given to flutter echoes and achievement of diffuse sound fields. The inner shell construction was built up using special acoustical building blocks. Besides using double walls, the broad analysis was done in order to avoid any possible problem in sound insulation. The achieved coincident frequency for walls and floors is 7.6 Hz, and this is quite satisfactory. The computer simulation was used during the design of internal sound-absorbing and reflecting surfaces. Described solutions take care of all user demands, as well as the usage particularities of such spaces. The measurements of relevant acoustical parameters were done after the building was finished.

The acoustic comfort of classrooms in a Brazilian public school has been evaluated through interviews with 62 teachers and 464 pupils and measurements of background noise, reverberation time, and sound insulation. Acoustic measurements have revealed the poor acoustic quality of the classrooms. Results have shown that teachers and pupils consider the noise generated and the voice of the teacher in neighboring classrooms as the main sources of annoyance inside the classroom. Acoustic simulations resulted in the suggestion of placement of perforated plywood on the ceiling, for reduction in reverberation time and increase in the acoustic comfort of the classrooms. [Work supported by DAAD, CNPq and FINEP.]

Chapter 4 – Migration research and analysis: Growth, reach and recent contributions

Fundamentals of Sound Waves and Hearing. Sound Waves. Speed of Sound. Impetence. Noise and Vibration - Measurement and Rating. Measurement of Sound/Noise. Noise Rating. Measurement of Vibration. Room Acoustics. Sound Field in a Room. Normal Modes of Vibration in Rooms. Reverberation Time. Sound Absorption - Materials and Construction. Types of Sound Absorption Mechanisms. Measurement of Absorption Coefficient and Acoustic Impetence. Characteristics of Porous Sound Absorber. Airborne Sound Insulation. Propagation and Transmission of Airborne Sound. Measurement and Rating of Airborne Sound Insulation. Mass Law for Sound Insulation of a Single Wall. Isolation of Structure-borne Noise and Vibration. Propagation and Radiation of Structure-borne Sound. Reduction of Structure-borne Noise. Measurement and Rating of Impact Sound Insulation. Noise and Vibration Control in the Environment. Basic Strategy. Determination of Required Reduction. Plan for Dealing with Noise and Vibration Sources. Acoustic Design of Rooms. Design Target. Design of Room Shape. Planning the Reverberation. Electro-acoustic systems. Function and Aim of Electro-acoustic Systems. Reinforcement Systems and Architectural Design. Prevention of Howling. Agenda. Wave Equation. Analogues in Electrical, Mechanical and Acoustic Systems and Time Constant. Fourier Transformation and Correlation Functions.