scholarly journals Influence of Sound-Absorbing Material Placement on Room Acoustical Parameters

Acoustics ◽  
2019 ◽  
Vol 1 (3) ◽  
pp. 644-660 ◽  
Author(s):  
Jose Cucharero ◽  
Tuomas Hänninen ◽  
Tapio Lokki
Keyword(s):  
Speech Intelligibility ◽  
Sound Absorption ◽  
Sound Field ◽  
Acoustical Parameters ◽  
Open Plan ◽  
Absorbing Material ◽  
The Impact

The reverberation of a room is often controlled by installing sound absorption panels to the ceiling and on the walls. The reduced reverberation is particularly important in classrooms to maximize the speech intelligibility and in open-plan offices to make spaces more pleasant. In this study, the impact of the placement of the absorption material in a room was measured in a reverberation room and in a mockup classroom. The results show that absorption material is less efficient if it is mounted to the corners or on the edges between the walls and ceiling, if the sound field is more or less diffuse. If the room modes dominate the sound field, the most efficient location for the sound-absorbing material was found at one of the surfaces causing the modes. The results help acoustical consultants to place the absorption material in optimal locations and, generally, minimize the amount of material and save costs.

scholarly journals The influence of the distribution of sound absorbing materials on the estimation of reverberation time in rooms

2018 ◽  
Vol 49 ◽  
pp. 00078
Author(s):  
Marcelina Olechowska ◽  
Artur Nowoświat ◽  
Jan Ślusarek ◽  
Mateusz Latawiec
Keyword(s):  
Absorption Coefficient ◽  
Acoustic Field ◽  
Sound Absorption ◽  
Sound Field ◽  
Reverberation Time ◽  
Type D ◽  
Absorbing Materials ◽  
Absorbing Material ◽  
Different Dimensions ◽  
Materials Used

Reverberation time in rooms depends on many factors, e.g. cubature, surface of envelopes, sound absorption coefficient of materials used for the construction of the envelopes, geometry of rooms or the distribution of sound absorbing materials. The arrangement of sound absorbing materials in rooms has an impact on the dispersion of acoustic field, yet theoretical calculation models do not take into account this impact. According to these models, regardless of the arrangement of sound absorbing materials, the reverberation time in a room will remain unchanged. The present paper investigates the above problem by means of computer simulations. For the needs of the simulation, three rooms with different dimensions were adopted, i.e. type 'p' - a cuboidal room with a square base, type 'd' - a cuboidal room (with one side of the 'p' room lengthened), type 'w' - a cuboidal room (with the height of the room lengthened 'p'). During the simulation, the way of acoustic field dispersion was being changed and its influence on the reverberation time in the rooms was being determined. The authors investigated two situations. The first one involved a non-dampened room, in which the sound absorbing material was being arranged differently. The second one involved a welldampened room, and the dispersion of sound field was analyzed depending on the location of the reflecting material.

The effects of intelligible irrelevant background speech in offices – cognitive disturbance, annoyance, and solutions

Facilities ◽  
2015 ◽  
Vol 33 (1/2) ◽  
pp. 61-75 ◽  
Author(s):  
Sabine J. Schlittmeier ◽  
Andreas Liebl
Keyword(s):  
Cognitive Performance ◽  
Speech Intelligibility ◽  
Empirical Studies ◽  
Experimental Studies ◽  
Two Dimensions ◽  
Subjective Ratings ◽  
Severe Problem ◽  
Content Type ◽  
Open Plan ◽  
The Impact

Purpose – This paper aims to give an overview on four empirical studies which explored the impact of background speech on cognitive performance and subjectively perceived disturbance. Background speech is the most serious noise problem in shared-room and open-plan offices for employees who are supposed to do silent, concentrated work. Different measures of acoustic office optimization, as well as the outstanding role of the intelligibility of background speech for its disturbance impact, are empirically evaluated. Design/methodology/approach – The article provides a synopsis describing the core empirical results of four of our empirical studies. A survey study among office employees (n = 659) explored the subjective importance of office acoustics. Three experimental studies (n1 = 20; n2 = 30; n3 = 24) evaluated the effects of reduced background speech level, play-back of partial maskers and reduced speech intelligibility on cognitive performance and subjective ratings. Findings – Background speech is subjectively perceived as a severe problem, and the different noise abatement measures affect objective performance and subjective ratings differently. Speech intelligibility is – besides level – a key determinant for the acoustic optimization regarding these two dimensions. Research limitations/implications – Practitioners are encouraged to apply the findings and described measures when planning and/or evaluating open-plan offices. Practical implications – It is concluded that different acoustically efficient measures need to be combined to minimize the negative effects of background speech on cognitive performance and subjectively perceived disturbance. The aspired set value for open-office concepts is the lowest possible sound level with a bad intelligibility of the background speech at the same time. Originality/value – The synopsis of several empirical studies allows deriving comprehensive and well-founded information for practitioners involved in the evaluation and/or design of offices environments.

scholarly journals The Influence of Yarn and Weave Structures on Acoustic Materials and the Effect of Different Acoustic Signal Incidence Angles on Woven Fabric Absorption Possibilities

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2814
Author(s):  
Bethalihem Teferi Samuel ◽  
Marcin Barburski ◽  
Jaroslaw R Blaszczak ◽  
Ewa Witczak ◽  
Katarzyna Abramczyk
Keyword(s):  
Sound Absorption ◽  
Structure Type ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Polyester Yarn ◽  
Absorption Properties ◽  
Internal Structures ◽  
Absorbing Material ◽  
Points Of View ◽  
The Impact

Utilizing textile-based acoustic materials can be considered basically from two points of view. First, it may be used as a sound absorbing material. Second, it may be used as a decoration that gives the surrounding area a new artistic appearance. To improve the acoustic possibilities of any woven fabric, it is necessary to study the influences of yarn characteristics and the internal structures of weave interlacement. To understand the impact of the yarn on the fabric, the samples were prepared using only polyester fiber as textured, twisted, and staple yarns. Regarding this experiment, the basic weave’s structure type, such as plain, rib, sateen, and twill, were used. Overall, 16 woven fabrics were prepared. The investigation was performed in the range of low to medium acoustic frequencies. The experiments were conducted in an anechoic chamber. Compared to other yarn types, fabrics formed from textured polyester yarn had higher sound absorption properties. Moreover, the observed results show that the different incidence angles of acoustic signals influence the measured sound absorption properties of a textile.

scholarly journals Numerical Analysis of Indoor Sound Quality Evaluation Using Finite Element Method

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yu-Tuan Chou ◽  
Shao-Yi Hsia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Speech Intelligibility ◽  
Sound Absorption ◽  
Multipath Propagation ◽  
Sound Field ◽  
Interior Space ◽  
Environmental Friendliness ◽  
Indoor Space ◽  
Element Method

Indoors sound field distribution is important to Room Acoustics, but the field suffers numerous problems, for example, multipath propagation and scattering owing to sound absorption by furniture and other aspects of décor. Generally, an ideal interior space must have a sound field with clear quality. This provides both the speaker and the listener with a pleasant conversational environment. This investigation uses the Finite Element Method to assess the acoustic distribution based on the indoor space and chamber volume. In this situation, a fixed sound source at different frequencies is used to simulate the acoustic characteristics of the indoor space. This method considers the furniture and decoration sound absorbing material and thus different sound absorption coefficients and configurations. The preliminary numerical simulation provides a method that can forecast the distribution of sound in an indoor room in complex situations. Consequently, it is possible to arrange interior furnishings and appliances to optimize acoustic distribution and environmental friendliness. Additionally, the analytical results can also be used to calculate the Reverberation Time and speech intelligibility for specified indoor space.

Numerical study of the impact of reverberation room design and test parameters on sound absorption measurements

2021 ◽  
Vol 263 (4) ◽  
pp. 2372-2383
Author(s):  
Paul Didier ◽  
Cédric Van hoorickx ◽  
Edwin Reynders
Keyword(s):  
Sound Absorption ◽  
Numerical Study ◽  
Plane Waves ◽  
Sound Field ◽  
Analysis Model ◽  
Absorption Coefficients ◽  
Low Frequencies ◽  
Room Design ◽  
The Impact ◽  
Absorption Measurements

The measurement of sound absorption in reverberation rooms following the ISO 354:2003 standard relies on Sabine's equation to derive absorption coefficients from reverberation times. This equation assumes perfect diffusivity, i.e. the sound field is composed of many statistically independent plane waves with uniformly distributed spatial phases, themselves uncorrelated to the corresponding amplitudes. In this work, both existing and fictitious reverberation rooms are numerically modelled using the finite element method. Finite porous absorbers are introduced in the rooms as equivalent fluid models. Standardized sound absorption measurement are simulated in the rooms through the determination of reverberation times. The respective effects of the sample size, sample placement, source positioning, and presence of finite panel diffusers are investigated. The resulting absorption coefficients are then confronted to the theoretical values in a perfectly diffuse sound field, that interacts with a baffled, finite-sized absorber, as obtained with a hybrid deterministic-statistical energy analysis model. The process notably underlines the strong, yet often disregarded, beneficial effect of panel diffusers at low frequencies in highly regularly-shaped rooms. Another conclusion of this work is that reverberation room design represents a crucial factor that can influence sound absorption measurements at low frequencies.

scholarly journals Impact and Control of Reflected Noise from an Overpass Bottom

2018 ◽  
Vol 8 (10) ◽  
pp. 1908
Author(s):  
Chi-Chwen Lin ◽  
Yen-Ping Peng ◽  
Yung-Pin Tsai ◽  
Yu-Chen Chang ◽  
Ku-Fan Chen
Keyword(s):  
Noise Level ◽  
Sound Absorption ◽  
Noise Source ◽  
Model Simulation ◽  
Buffer Zone ◽  
Residential Area ◽  
Discernible Effect ◽  
Absorbing Material ◽  
And Control ◽  
The Impact

This study examines the effects of noise reflected from the overpass bottom under various conditions using onsite measurements and model simulation. Reflected noise from the overpass bottom may be as high as 8 dB(A). Bottom materials (steel and reinforced concrete (RC)) have no discernible effect on the reflected noise level. As the height of an overpass increases, the level of reflected noise decreases. When an overpass is parallel to the noise source (i.e., the freeway), the size of the area impacted by reflected noise increases. As the sound absorption rating of the material installed at the overpass bottom increased, the level of reflected noise decreased. A sound absorbing material with a sound absorption rate of at least 0.60 is recommended to reduce reflected noise level. When the distance between the overpass side and a receiver exceeded 30 m, the level of reflected noise level reduced significantly. Therefore, if the distance between a residential area and overpass could be increased to create a buffer zone coupled with the installation of sound absorbing material at the overpass bottom, the impact of reflected noise on nearby residents can be reduced.

Efficiency of the cochlear implantation in children with severe sensorineural hearing loss and deafness according to the data of speech audiometry in the free sound field and in the noise background

2018 ◽  
pp. 4-16
Author(s):  
Dmitry Zabolotny ◽  
Viktor Lutsenko ◽  
Irina Belyakova ◽  
Tetiana Kholodenko
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Cochlear Implantation ◽  
Speech Intelligibility ◽  
Sound Field ◽  
Sensorineural Hearing ◽  
Speech Audiometry ◽  
Noise Background ◽  
Useful Signal ◽  
The Impact

Relevance: Any kind of the hearing loss, especially in the childhood, affects the mental and intellectual development negatively as well as behavior and social position of a deaf patient in the hearing world. Cochlear implantation is the most effective and reliable method of medical and educational auditory-speech rehabilitation for both adults and children with severe hearing loss and deafness. One of the key performance indicators of the cochlear implantation is a result of speech audiometry, especially on the noise background. The aim is to study the state of auditory function according to the subjective audiometry in the noise background and the influence of various factors on the effectiveness of rehabilitation of the children after cochlear implantation. Materials and methods: The study involved 150 children with severe sensorineural hearing loss and deafness after cochlear implantation. In age, they ranged from 3 to 18 years old. Evaluation of the efficiency of cochlear implantation was carried out in several stages. All studies were done in the free-field with the cochlear implant on. At first, we performed the pure tone audiometry. Then we defined the 50% intelligibility threshold of numeral test. After that, we defined a word recognition percentage. And finally we defined the impact of masker on speech intelligibility at SPL of useful signal 50, 60 and 80 dB. Results: Based on the analysis of the received data, all children with severe sensorineural hearing loss and deafness after cochlear implantation were divided into 3 groups depending on the speech intelligibility. The first group (high efficiency of cochlear implantation) included 68 children (45,3%). This group was divided into two subgroups depending on the difference between the values of the speech intelligibility in the free sound field and in the noise background. The second group (average efficiency) consisted of 45 children (30%). The third group (low efficiency) were 37 children (24,7%). The influence of various factors on the efficiency of cochlear implantation was analyzed. Conclusion: Speech intelligibility in the noise background must be examinated in all children after cochlear implantation. The main factors affecting the effectiveness of cochlear implantation according to test of speech intelligibility in the noise background are the ethiology of hearing loss and duration of post-operation period. Results of speech intelligibility in the noise background test will help specialists who practice the rehabilitation of children after cochlear implantation (teachers for deaf, speech therapists) to pay attention to the decrease of speech intelligibility in children in the real conditions of communication and to focus their efforts on its improving with the appropriate methods.

Translating Principles of Speech Science to Clinical Practice: Current and Future Trends in Craniofacial Disorders

2008 ◽  
Vol 18 (1) ◽  
pp. 31-40 ◽  
Author(s):  
David J. Zajac
Keyword(s):  
Clinical Practice ◽  
Speech Intelligibility ◽  
Current Practice ◽  
Computer Assisted ◽  
Behavioral Management ◽  
Single Word ◽  
Future Directions ◽  
Speech Science ◽  
The Impact ◽  
Opinion Article

Abstract The purpose of this opinion article is to review the impact of the principles and technology of speech science on clinical practice in the area of craniofacial disorders. Current practice relative to (a) speech aerodynamic assessment, (b) computer-assisted single-word speech intelligibility testing, and (c) behavioral management of hypernasal resonance are reviewed. Future directions and/or refinement of each area are also identified. It is suggested that both challenging and rewarding times are in store for clinical researchers in craniofacial disorders.

Speech Intelligibility Parameters for Evaluating the Perception of Background Noise in Open-Plan Office Users: A Case Study

2021 ◽  
Author(s):  
María Serrano Ruiz
Keyword(s):  
Background Noise ◽  
Speech Intelligibility ◽  
Acoustic Analysis ◽  
Physical Factors ◽  
Space Design ◽  
Transmission Index ◽  
Open Plan ◽  
Design Characteristics

This document presents a case study of acoustic analysis in an open-plan office. Since Mexico does not have a standard for evaluating acoustic conditions in offices, it is relevant to compare different acoustic evaluation methods used for open-plan offices. According to several studies, one of the main acoustic characteristics for open-plan office spaces is speech intelligibility. Therefore, the purpose of this document is to compare psychoacoustic parameters to evaluate speech intelligibility in open-plan offices. We analyzed physical factors as reverberation and speech clarity in different office points, as well as semantic factors based on subjective methods with standardized values of the quality of speech intelligibility. The study was carried out under real open-plan office conditions in a library in a university in northern Mexico. The study factors of interest were type of sound, sound source, and location of the listener, with Reverberation Time (RT), Speech Transmission Index (STI) and Loss of consonant articulation (%ALCons) as the measures of impact on intelligibility. This case study provides additional evidence of the relationship between intelligibility and the position of sound sources; also, it was noted that location of listeners influenced analyzed intelligibility parameters. On the other hand, this case study offers information concerning to use psychoacoustic parameters for subjective classification of quality of the speech intelligibility to evaluate how is background noise perceived in open-plan office users. However, it is noteworthy that this study represents a single office with its own interior and space design characteristics.

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