The Assessment of Acoustical Characteristics for Recent Mosque Buildings in Erbil City of Iraq

The study of mosque acoustics, concerning acoustical features, sound quality for speech intelligibility, and additional practical acoustic criteria, is commonly overlooked. Acoustic quality is vital to the fundamental use of mosques, in terms of contributing toward prayers and worshippers’ appreciation. This paper undertakes a comparative analysis of the acoustic quality level and the acoustical characteristics for two modern mosque buildings constructed in Erbil city. This work investigates and examines the acoustical quality and performance of these two mosques and their prayer halls through room simulation using ODEON Room Acoustics Software, to assess the degree of speech intelligibility according to acoustic criteria relative to the spatial requirements and design guidelines. The sound pressure level and other room-acoustic indicators, such as reverberation time (T30), early decay time, and speech transmission index, are tested. The outcomes demonstrate the quality of acoustics in the investigated mosques during semi-occupied and fully-occupied circumstances. The results specify that the sound quality within the both mosques is displeasing as the loudspeakers were off.

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Improved Room Acoustics Quality in Meeting Rooms: Investigation on the Optimal Configurations of Sound-Absorptive and Sound-Diffusive Panels

Acoustics ◽

10.3390/acoustics2030025 ◽

2020 ◽

Vol 2 (3) ◽

pp. 451-473 ◽

Cited By ~ 1

Author(s):

Laura Labia ◽

Louena Shtrepi ◽

Arianna Astolfi

Keyword(s):

Optimal Number ◽

Optimal Placement ◽

Room Acoustics ◽

Acoustic Measurements ◽

Transmission Index ◽

Speech Transmission ◽

Acoustic Quality ◽

Optimal Configurations ◽

And Diffusion

This work deals with the improvement of the room acoustic quality of two medium sized meeting rooms through the investigation of the optimal placement of absorption and diffusive panels on the walls and ceiling. Acoustic measurements have been carried out in the existing untreated rooms with ODEON 13 room acoustics measurement and prediction software, and the Adobe Audition plugins Aurora. Simulations of different combinations of sound absorption and diffusion treatments have been carried out with the updated version of the software, ODEON 15. The panels were positioned in the meeting rooms following the guidelines of the DIN 18041 standard and the scientific literature. The results advise the application of absorptive materials on the ceiling or around the borders, creating a reflective middle area, and on the upper part of one the lateral walls, including the rear wall. Configurations with diffusers do not generally bring significant improvements. The Speech Transmission Index (STI) is a less sensitive parameter for the different acoustic scenarios, compared to Reverberation Time (T) and Clarity (C50). The research also outlined a design workflow, useful to successfully design meeting rooms and rooms for speech in general, which allows to determine the optimal number and location of acoustic panels and to minimize the costs.

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Acoustic quality assessment in a classroom through simulations and measurements

Revista Nacional de Gerenciamento de Cidades ◽

10.17271/2318847297220213014 ◽

2021 ◽

Vol 9 (72) ◽

Author(s):

Eriberto Oliveira do Nascimento ◽

Paulo Henrique Trombetta Zannin

Keyword(s):

Background Noise ◽

Speech Intelligibility ◽

Reverberation Time ◽

Vocal Health ◽

Quality Requirements ◽

Transmission Index ◽

Speech Transmission ◽

Acoustic Quality ◽

Acoustic Comfort ◽

Minimum Requirements

The acoustic quality in a classroom directly impacts the educational relationship between the student and the teacher, reducing speech intelligibility. In addition, inadequate acoustic comfort burdens the vocal health of teachers. This study evaluated a classroom at the Federal University of Paraná, Campus Centro Politécnico, to verify its acoustic quality. The measurements of the acoustics descriptors: Reverberation Time (RT), Definition (D50), Central Time (Ts), Early Decay Time (EDT) were performed according to the ISO 3382-2 standard, concerning Noise Curves (NC) and Background Noise (BGN) these were evaluated by the NBR 10152 and S12.2 standards. The Speech Transmission Index (STI) was measured according to IEC 60268-16 and evaluated according to ISO 9921. The useful-detrimental ratio (U50) and the other descriptors were simulated in the ODEON software version 11. Thus, the results showed that the evaluated room did not meet the minimum requirements in terms of acoustic quality, for the descriptors RT, STI, Ts, D50, RF, and NC. Simultaneously, the RT and STI were also outside the limits established by the German and Finnish standards. Therefore, it is concluded that the evaluated classroom did not reach the minimum acoustic quality requirements.

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A Study of the Acoustics and Speech Intelligibility Quality of Mosques in Malaysia

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.564.129 ◽

2014 ◽

Vol 564 ◽

pp. 129-134

Author(s):

Abdul Hakim Abdullah ◽

Zamir A. Zulkefli

Keyword(s):

Background Noise ◽

Speech Intelligibility ◽

Prediction Models ◽

Signal To Noise Ratio ◽

Distribution Patterns ◽

Speech Quality ◽

Transmission Index ◽

Speech Transmission ◽

Rapid Transmission

This study presents the assessment of the quality of speech intelligibility of two Malaysian mosques and the results are used to develop a set of general acoustical guidelines to be used in the design of a mosque. Two mosques were selected for the research: Masjid UPM and the Masjid Jamek. The objective of the research is to enable the comparison of the acoustics and speech intelligibility between the mosques as function of the size, volume, occupancy and other parameters of the main prayer hall on the acoustic and speech intelligibility of the respective mosques. The reverberation time (RT60), speech level (SL), background noise (BN), signal-to-noise ratio (S/N ratio) were determined and are used to develop the speech transmission index (STI) and rapid transmission index (RASTI) prediction models for both mosques. It was observed from the results that the RT60, STI and RASTI values shows better performance over number of occupancy for both mosques. Furthermore, the BN and SL results were visualized using the spatial distribution patterns (SDP) of the main hall. The results of the analysis show that the overall acoustic and speech quality of Masjid Jamek is better when compared to the overall acoustic and speech quality of Masjid UPM. These results are then used to develop a set of design recommendations to ensure adequate speech intelligibility quality a mosque.

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Comparison of Two Types of Combined Measures, STI and U50, for Predicting Speech Intelligibility in Classrooms

Archives of Acoustics ◽

10.1515/aoa-2017-0056 ◽

2017 ◽

Vol 42 (3) ◽

pp. 527-532 ◽

Cited By ~ 2

Author(s):

Young-Ji Cho

Keyword(s):

Speech Intelligibility ◽

Room Acoustics ◽

Speech Communication ◽

Modulation Transfer ◽

Acoustic Measurements ◽

Transmission Index ◽

Speech Transmission ◽

The Mean ◽

University Classrooms ◽

Made In

AbstractThe present study reports on the speech intelligibility as measured by speech transmission index (STI) and useful-to-detrimental sound ratios (U50) in university classrooms. Acoustic measurements were made in 12 quietly occupied university classrooms. The measured impulse responses of the classrooms were used to determine the modulation transfer function, m(F), for the STI calculation according to IEC 60268-16. U50values were determined from both signal-to-noise ratios (SNR) and C50values. The mean STI and frequency-weighted U50values for the 12 occupied classrooms were strongly linearly related. The results showed that classrooms with U50values of about +0.5 dB correspond to STI values of 0.60, indicating ‘good’ acoustical conditions for speech intelligibility. The results illustrate that the U50measure can be a more practically useful means of assessing and understanding room acoustics conditions for real speech communication in active classrooms.

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Prediction and Evaluation of Emergency Broadcasting Sound and Speech Intelligibility for Safety Zones in High-rise Buildings

Fire Science and Engineering ◽

10.7731/kifse.91d2fd5b ◽

2020 ◽

Vol 34 (6) ◽

pp. 37-43

Author(s):

Jeong-Ho Jeong

Keyword(s):

Fire Safety ◽

Speech Intelligibility ◽

Detection System ◽

Simulation Method ◽

Room Acoustics ◽

Radio Communication ◽

Safety Zone ◽

High Rise ◽

Transmission Index ◽

Speech Transmission

As construction of high-rise buildings is increasing, the installation of a fire safety zone for the safe evacuation of residents has become mandatory. Even for building complexes with an underground connection between 30 and 49 stories, a fire safety zone must be installed when the residential density exceeds 1.5 people per square meter. In the fire safety zone, an automatic fire detection system and a system to assist radio communication must be installed. In addition, an emergency broadcasting system must be installed to announce the fire situation and to guide the safe evacuation of the residents. The fire safety zone was constructed with non-combustible material to minimize flames or smoke and was furnished to maintain a very low fire load. However, non-combustible materials have very low sound absorption characteristics; therefore, they usually reflect the sound energy into the spaces. In spaces consisting of sound reflective materials, the emergency broadcasting sounds reverberated, making it difficult to understand the meaning of the broadcasted sound. In this study, the room acoustics characteristics for fire safety zones in a high-rise building, represented as reverberation time and speech transmission index, were predicted using a certified room acoustics simulation method and evaluation of speech intelligibility. As a result of predicting the acoustic characteristics of the safety zone, it was found that the space had quite long reverberation and speech intelligibility was low, making it difficult to clearly transmit the emergency broadcast sound. When a safety zone was set up in a part of the machinery room, it was confirmed that it was difficult to clearly transmit the emergency broadcast sound, even when the background noise level was louder than 70 dB(A). To deliver a clear emergency broadcast sound in the safety zone, it is necessary to use inorganic sound-absorbing materials and to properly block noise in the machine room. In addition, it is necessary to establish guidelines for regulation of the speech transmission index for emergency broadcasting systems.

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

10.47461/isoes.2021_021 ◽

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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Binaural speech-to-noise loudness ratio at the speech reception threshold in vehicles

Noise Control Engineering Journal ◽

10.3397/1/376917 ◽

2021 ◽

Vol 69 (2) ◽

pp. 173-179

Author(s):

Nilolina Samardzic ◽

Brian C.J. Moore

Keyword(s):

Speech Intelligibility ◽

New Method ◽

Traditional Methods ◽

Speech Reception ◽

Typical Error ◽

Transmission Index ◽

Speech Transmission ◽

Articulation Index ◽

Speech Intelligibility Index ◽

Binaural Listening

Traditional methods for predicting the intelligibility of speech in the presence of noise inside a vehicle, such as the Articulation Index (AI), the Speech Intelligibility Index (SII), and the Speech Transmission Index (STI), are not accurate, probably because they do not take binaural listening into account; the signals reaching the two ears can differ markedly depending on the positions of the talker and listener. We propose a new method for predicting the intelligibility of speech in a vehicle, based on the ratio of the binaural loudness of the speech to the binaural loudness of the noise, each calculated using the method specified in ISO 532-2 (2017). The method was found to give accurate predictions of the speech reception threshold (SRT) measured under a variety of conditions and for different positions of the talker and listener in a car. The typical error in the predicted SRT was 1.3 dB, which is markedly smaller than estimated using the SII and STI (2.0 dB and 2.1 dB, respectively).

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Environmental Acoustic Comfort in the Built Environment

Revista Nacional de Gerenciamento de Cidades ◽

10.17271/2318847297120212959 ◽

2021 ◽

Vol 9 (71) ◽

Author(s):

Margret Sibylle Engel ◽

Júlio Otávio Herrmann ◽

Paulo Henrique Trombetta Zannin

Keyword(s):

Teaching And Learning ◽

Physical Structure ◽

Sharp Drop ◽

Speech Transmission ◽

Acoustic Quality ◽

Teachers And Students ◽

Acoustic Comfort ◽

The 1960S ◽

Acoustic Conditions

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.

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