scholarly journals Acoustical Design and Noise Control in Metro Stations: Case Studies of the Ankara Metro System

2007 ◽  
Vol 14 (3) ◽  
pp. 203-221 ◽  
Author(s):  
Zühre Sü ◽  
Mehmet Çalışkan
Keyword(s):  
Computer Simulation ◽  
Nonwoven Material ◽  
Sound Level ◽  
Reverberation Time ◽  
Acoustical Parameters ◽  
Transmission Index ◽  
Speech Transmission ◽  
Absorbing Materials ◽  
Practical Design ◽  
Metro System

The aim of this research is to demonstrate the importance of initial strategies in acoustical design of underground metro stations. The paper searches for practical design solutions by evaluating different materials for providing optimum acoustical conditions in such spaces. Acoustical designs of three metro stations on a new expansion line in Ankara including Sogutozu, Bilkent and ODTU metro stations are presented through computer simulation. Predictions of room acoustical parameters are presented for both platform and ticket office floors in terms of parameters like reverberation time (RT), speech transmission index (STI) and A-weighted sound level (SPL) distribution within spaces. Simulated reverberation times are evaluated in view of legislative requirements. The study confirms the importance of using sound absorbing materials on the ceiling and sidewalls together. The nonwoven material, used behind perforated metal suspended ceilings, has proved effective in reverberation control.

scholarly journals Aspects regarding the acoustics of a lecture hall

2019 ◽  
Vol XXII (2) ◽  
pp. 268-275
Author(s):  
Pazara T.
Keyword(s):  
Speech Intelligibility ◽  
Great Influence ◽  
Lecture Hall ◽  
Naval Academy ◽  
Reverberation Time ◽  
Acoustical Parameters ◽  
Transmission Index ◽  
Speech Transmission ◽  
Virtual Simulations ◽  
Teaching Conditions

In a lecture hall it is vital to assure proper teaching conditions meaning that the information from the speaker/teacher must be received correctly by the listeners. Speech intelligibility is the main objective when a lecture hall is evaluated. In this paper, the authors discuss the importance of the acoustics of a lecture hall and the influence of various parameters over speech transmission from the speaker – the professors to the listeners – the students. The number of acoustical parameters is very large, but Speech Transmission Index (STI) and Reverberation Time (RT) are commonly used to evaluate the acoustics of a teaching room. Other parameters like room geometry and seat placement have great influence in speech intelligibility. As an example, a lecture hall of 120 seats from Naval Academy „Mircea cel Batran“ is investigated using virtual simulations with ODEON software. The results of the simulations are discussed and some remarks are made regarding the current condition of the lecture hall.

scholarly journals Assessing the Effect of Dome Shape and Location on The Acoustical Performance of a Mosque by Using Computer Simulation

2019 ◽  
Vol 16 (1) ◽  
pp. 6415-6426
Author(s):  
N. Che Din ◽  
A. S. Anuar
Keyword(s):  
Computer Simulation ◽  
Geometrical Approach ◽  
Sound Waves ◽  
Acoustical Parameters ◽  
Architectural Elements ◽  
Acoustical Parameter ◽  
Transmission Index ◽  
Speech Transmission ◽  
Different Shapes ◽  
Dome Shape

Architecturally, the dome is one evolutionary presence in most mosques of modern day. Besides mihrab, the dome is one of the architectural elements that has a phenomenon of concentration of energy by reflected sound waves from concave surfaces. The aim of this research is to compare the acoustical performance of different shapes of the dome and their respective locations by using geometrical approach computer simulation. Four types of dome that are commonly used on a mosque; Arabic, segmental, hemispherical, and onion, were modeled to compare their acoustical parameters i.e. reverberation time (RT) and speech transmission index (STI). It can be concluded that the shape of the dome does affect the RT. Furthermore, the shape of the dome also affects the STI - the larger the volume, the lower the STI value. However, the locations of a dome has little significance over acoustical parameter. The findings of this research may not limit to mosques only, but to any similar building that has similar typology.

The acoustics of ancient catacombs in Southern Italy

2020 ◽  
pp. 1351010X2096757 ◽  
Author(s):  
Giuseppe Ciaburro ◽  
Umberto Berardi ◽  
Gino Iannace ◽  
Amelia Trematerra ◽  
Virginia Puyana-Romero
Keyword(s):  
Roman Empire ◽  
Sound Source ◽  
Southern Italy ◽  
Reverberation Time ◽  
Acoustic Measurements ◽  
Acoustic Characteristics ◽  
Christian Religion ◽  
Renaissance Period ◽  
Transmission Index ◽  
Speech Transmission

The catacombs, burial sites for early Christians, were constructed during the Roman Empire until the Christian religion was recognized in 313 AD. The catacombs were cementeries, which were organized according to precise rules and were dug into the ground on several levels, to occupy as little space as possible. The catacombs became places of worship as martyrs were buried in them. The catacombs were then abandoned with the barbarian invasions and the consequent construction of churches inside cities. The catacombs were rediscovered during the Renaissance period and became a place of renewed worship. In the present work, the acoustic characteristics of the catacombs of San Callisto in Rome, San Gennaro in Naples, and Vigna Cassia in Syracuse are discussed. The three selected catacombs differ by type of excavation and geometry. In particular, the catacombs of San Callisto are made of narrow corridors and small rooms; the catacombs of San Gennaro consist of large rooms with niches; the catacombs of Vigna Cassia are partly excavated in the tuff and partially occupy a disused aqueduct. The acoustic measurements were performed using an impulsive sound source. The description of the acoustic characteristics focuses on the reverberation time and the Speech Transmission Index. The results show that the reverberation time was always shorter than 1 second, confirming the reduced reverberation of these environments. Finally, the speech listening characteristics are particularly good, ensuring the suitable conditions for the prayer in these spaces.

Acoustics of Classrooms in Primary Schools - Results of the Reverberation Time and the Speech Transmission Index Assessments in Selected Buildings

2011 ◽  
Vol 36 (4) ◽  
pp. 777-793 ◽  
Author(s):  
Witold Mikulski ◽  
Jan Radosz
Keyword(s):  
Correlation Analysis ◽  
Primary Schools ◽  
Building Construction ◽  
Acoustic Properties ◽  
School Building ◽  
Reverberation Time ◽  
Frequency Range ◽  
Transmission Index ◽  
Speech Transmission ◽  
Precise Assessment

Abstract The article presents results of our own research regarding acoustic properties of 110 classrooms in five typical primary schools in Warsaw. The target of the research was to assess the classrooms using established criteria. These criteria include the reverberation time and the speech transmission index. The research has shown a large diversity of acoustic properties of classrooms within each of the schools and between the schools, resulting from the classroom equipment and the school building construction. In addition, the assessment has indicated that classrooms in schools researched do not meet the established acoustic criteria (reverberation time and speech transmission index). Because the classroom equipment is different for younger forms (integrated teaching) and for older forms (subject teaching), the results have been analyzed separately for rooms for younger forms (0-III) and for rooms for older forms (IV-VI). Synthetic results prove the advisability of such division. Correlation analysis has been conducted for the speech transmission index STI and reverberation time Tmf, as well as for the speech transmission index STI and the suggested reverberation time Twf defined in a similar manner as Tmf, but in a wider frequency range. The correlation between the speech transmission index STI and Twf is higher than that between the STI index and Tmf. The reverberation time Twf can therefore be used for a more precise assessment of acoustic properties of interiors with regard to verbal communication than Tmf. In addition, the paper presents estimated analysis results of the influence of selected classroom equipment (carpets) on its acoustic properties.

scholarly journals Logatome and Sentence Recognition Related to Acoustic Parameters of Enclosures

2017 ◽  
Vol 42 (3) ◽  
pp. 385-394
Author(s):  
Jedrzej Kocinski ◽  
Edward Ozimek
Keyword(s):  
Speech Recognition ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Acoustic Parameters ◽  
Music School ◽  
Sentence Recognition ◽  
Speech Reception ◽  
Middle Range ◽  
Transmission Index ◽  
Speech Transmission

AbstractThe paper deals with relationship between speech recognition and objective parameters of enclosures. Six enclosures were chosen: a church, an assembly hall of a music school, two courtrooms of different volumes, a typical auditorium and a university concert hall. Dirac 4.1 software was used to record impulse responses (IRs) in the chosen measurement points of each enclosure. On this base, the following objective parameters of the enclosure were determined: Reverberation Time (RT), Early Decay Time (EDT), Weighted Clarity (C50) and Speech Transmission Index (STI). A convolution of the IRs with logatome tests and the Polish Sentence Test (PST) was made. Logatome recognition and speech reception threshold (SRT - i.e., SNR yielding 50% speech recognition) were evaluated and their dependence on the objective parameters were determined. Generally a linear relationship between logatome or SRT and RT or EDT was found. However, speech recognition was nonlinearly related (according to psychometric function) to STI values. The most sensitive range of the logatome and sentence recognition relative to STI changes corresponded to the middle range of STI values. Below and above this range, logatome and sentence recognition were much less dependent of STI changes.

scholarly journals Acoustic quality assessment in a classroom through simulations and measurements

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.

Speech Recognition in an Enclosure with a Long Reverberation Time

2016 ◽  
Vol 41 (2) ◽  
pp. 255-264
Author(s):  
Jędrzej Kociński ◽  
Edward Ozimek
Keyword(s):  
Speech Intelligibility ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Speech Reception ◽  
Transmission Index ◽  
Speech Transmission ◽  
Amplification System ◽  
The Difference ◽  
Sound Amplification ◽  
Relationship Of

Abstract The aim of this work was to measure subjective speech intelligibility in an enclosure with a long reverberation time and comparison of these results with objective parameters. Impulse Responses (IRs) were first determined with a dummy head in different measurement points of the enclosure. The following objective parameters were calculated with Dirac 4.1 software: Reverberation Time (RT), Early Decay Time (EDT), weighted Clarity (C50) and Speech Transmission Index (STI). For the chosen measurement points, a convolution of the IRs with the Polish Sentence Test (PST) and logatome tests was made. PST was presented at a background of a babble noise and speech reception threshold - SRT (i.e. SNR yielding 50% speech intelligibility) for those points were evaluated. A relationship of the sentence and logatome recognition vs. STI was determined. It was found that the final SRT data are well correlated with speech transmission index (STI), and can be expressed by a psychometric function. The difference between SRT determined in condition without reverberation and in reverberation conditions appeared to be a good measure of the effect of reverberation on speech intelligibility in a room. In addition, speech intelligibility, with and without use of the sound amplification system installed in the enclosure, was compared.

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