scholarly journals Assessment of speech intelligibility in university lecture rooms of different sizes using objective and subjective methods

2021 ◽  
Vol 3 (5 (111)) ◽  
pp. 47-56
Author(s):  
Arkadiy Prodeus ◽  
Maryna Didkovska

The scores of speech intelligibility, obtained using objective and subjective methods for three university lecture rooms of the small, medium, and large sizes with different degrees of filling, were presented. The problem of achieving high speech intelligibility is relevant for both students and university administration, and for architects designing or reconstructing lecture rooms. Speech intelligibility was assessed using binaural room impulse responses which applied an artificial head and non-professional quality audio equipment for measuring. The Speech Transmission Index was an objective measure of speech intelligibility, while the subjective evaluation of speech intelligibility was carried out using the articulation method. Comparative analysis of the effectiveness of parameters of impulse response as a measure of speech intelligibility showed that Early Decay Time exceeded the score of the T30 reverberation time but was ineffective in a small lecture room. The C50 clarity index for all the considered lecture rooms was the most informative. Several patterns determined by the influence of early sound reflections on speech intelligibility were detected. Specifically, it was shown that an increase in the ratio of the energy of early reflections to the energy of direct sound leads to a decrease in speech intelligibility. The exceptions are small, up to 30‒40 cm, distances from the back wall of the room, where speech intelligibility is usually slightly higher than in the middle of the room. At a distance of 0.7–1.7 m from the side walls of the room, speech intelligibility is usually worse for the ear, which is closer to the wall. The usefulness of the obtained results lies in refining the quantitative characteristics of the influence of early reflections of sound on speech intelligibility at different points of lecture rooms.

2016 ◽  
Vol 41 (2) ◽  
pp. 255-264
Author(s):  
Jędrzej Kociński ◽  
Edward Ozimek

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.


2021 ◽  
Vol 69 (2) ◽  
pp. 173-179
Author(s):  
Nilolina Samardzic ◽  
Brian C.J. Moore

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).


Acoustics ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 423-438 ◽  
Author(s):  
Zorana Đorđević ◽  
Dragan Novković ◽  
Uroš Andrić

The acoustic analysis provides additional information on building tradition and related indoor practice that includes sound, thus deepening our understanding of architectural heritage. In this paper, the sound field of the Orthodox medieval church Lazarica (Kruševac city, Serbia) is examined. Lazarica is a representative of Morava architectural style, developed in the final period of the Serbian medieval state, when also the chanting art thrived, proving the importance of the aural environment in Serbian churches. The church plan is a combination of a traditional inscribed cross and a triconch. After the in situ measurement of acoustic impulse response using EASERA software, we built a computer model in the acoustic simulation software EASE and calibrated it accordingly. Following the parameters (reverberation time (T30), early decay time (EDT) and speech transmission index (STI)), we examined the acoustic effect of the space occupancy, central dome and the iconostasis. In all the cases, no significant deviation between T30 and EDT parameter was observed, which indicates uniform sound energy decay. Closing the dome with a flat ceiling did not show any significant impact on T30, but it lowered speech intelligibility. The height of iconostasis showed no significant influence on the acoustics of Lazarica church.


2009 ◽  
Vol 16 (3) ◽  
pp. 283-297 ◽  
Author(s):  
Menino A. S. M. P. Tavares ◽  
S. Rajagopalan ◽  
Satish J. Sharma ◽  
António P. O. Carvalho

The results presented here are based on field measurements carried out in six Catholic churches (Goa, India). Rapid Speech Transmission Index ( RASTI) and Subjective Speech Intelligibility ( SSI) measurements were made in four different seating zones of a church for three speech source locations (altar, pulpit, high altar), two languages (English, Konkani) and two postures (standing, sitting). The effects of language and postures were not significant. The altar location and the sanctuary of the church were preferable for speech intelligibility. Although the altar location showed better averages than the other speech source locations, the best predictive relationship between RASTI and SSI was the exponential growth of RASTI for the high altar source location with SSI for the English language.


1998 ◽  
Vol 5 (1) ◽  
pp. 57-68 ◽  
Author(s):  
L. El-Zeky ◽  
D.J. Oldham

A potential problem encountered with open stage auditoria is poor speech intelligibility arising from the directional nature of human speech sources. The conventional technique of employing large overhead reflecting surfaces to ensure a large early energy fraction to improve intelligibility is shown to be unsuitable in this situation. The use of Virtual Reflectors consisting of microphones and loudspeakers symmetrically located relative to the stage is proposed as a possible solution to the problems of open stage auditoria. It is suggested that the Speech Transmission Index is a suitable parameter for assessing the performance of Virtual Reflectors when in use and that computer modelling could provide a suitable method for investigating the action of Virtual Reflectors.


Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6320
Author(s):  
Piotr Odya ◽  
Jozef Kotus ◽  
Adam Kurowski ◽  
Bozena Kostek

The paper aims to discuss a case study of sensing analytics and technology in acoustics when applied to reverberation conditions. Reverberation is one of the issues that makes speech in indoor spaces challenging to understand. This problem is particularly critical in large spaces with few absorbing or diffusing surfaces. One of the natural remedies to improve speech intelligibility in such conditions may be achieved through speaking slowly. It is possible to use algorithms that reduce the rate of speech (RoS) in real time. Therefore, the study aims to find recommended values of RoS in the context of STI (speech transmission index) in different acoustic environments. In the experiments, speech intelligibility for six impulse responses recorded in spaces with different STIs is investigated using a sentence test (for the Polish language). Fifteen subjects with normal hearing participated in these tests. The results of the analytical analysis enabled us to propose a curve specifying the maximum RoS values translating into understandable speech under given acoustic conditions. This curve can be used in speech processing control technology as well as compressive reverse acoustic sensing.


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