Further Validation of the Speech Transmission Index (STI)

1987 ◽  
Vol 30 (3) ◽  
pp. 403-410 ◽  
Author(s):  
Larry E. Humes ◽  
Stephen Boney ◽  
Faith Loven
Keyword(s):  
Speech Recognition ◽  
Background Noise ◽  
Recognition Task ◽  
Sound Field ◽  
Normal Hearing ◽  
Noise Levels ◽  
Transmission Index ◽  
Speech Transmission ◽  
Binaural Listening ◽  
Prospective Analyses

The present article further evaluates the accuracy of speech-recognition predictions made according to two forms of the Speech Transmission Index (STI) for normal-hearing listeners. The first portion of this article describes the application of the modified Speech Transmission Index (mSTI) to an extensive set of speech-recognition data. Performance of normal-hearing listeners on a nonsense-syllable recognition task in 216 conditions involving different speech levels, background noise levels, reverberation times and filter passbands was found to be monotonically related to the mSTI. The second portion of this article describes a retrospective and prospective analysis of an extended sound-field version of the STI, referred to here as STI x . This extended STI considers many of the variables relevant to sound-field speech recognition, some of which are not incorporated in the mSTI. These variables include: (a) reverberation time; (b) speech level; (e) noise level; (d) talker-to-listener distance; (e) directivity of the speech source; and (f) directivity of the listener (eg., monaural vs. binaural listening). For both the retrospective and prospective analyses, speech-recognition was found to vary monotonically with STI x .

Speech Recognition in Background Noise: Monaural versus Binaural Listening Conditions in Normal-hearing Patients

2001 ◽  
Vol 22 (5) ◽  
pp. 625-630 ◽  
Author(s):  
Pekka Persson ◽  
Henrik Harder ◽  
Stig Arlinger ◽  
Bengt Magnuson
Keyword(s):  
Speech Recognition ◽  
Background Noise ◽  
Normal Hearing ◽  
Binaural Listening

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

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).

scholarly journals Comparison of Acceptable Noise Level Generated Using Different Transducers and Response Modes

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Liang Xia ◽  
Jingchun He ◽  
Yuanyuan Sun ◽  
Yi Chen ◽  
Qiong Luo ◽  
...  
Keyword(s):  
Noise Level ◽  
Sound Field ◽  
Normal Hearing ◽  
Noise Levels ◽  
Presentation Modes ◽  
Significant Difference ◽  
Acceptable Noise Level ◽  
The Subject ◽  
Response Modes ◽  
Chinese Subjects

The acceptable noise level (ANL) was defined by subtracting the background noise level (BNL) from the most comfortable listening level (MCL) (ANL = MCL − BNL). This study compared the ANL obtained through different methods in 20 Chinese subjects with normal hearing. ANL was tested with Mandarin speech materials using a loudspeaker or earphones, with each subject tested by himself or by the audiologist. The presentation and response modes were as follows: (1) loudspeaker with self-adjusted noise levels using audiometer controls (LS method); (2) loudspeaker with the subject signaling the audiologist to adjust speech and noise levels (LA method); (3) earphones with self-adjusted noise levels using audiometer controls (ES method); and (4) earphones with the subject signaling the audiologist to adjust speech and noise levels (EA method). ANL was calculated from three measurements with each method. There was no significant difference in the ANL obtained through different presentation modes or response modes sound. The correlations between ANL, MCL, and BNL obtained from each two methods were significant. In conclusion, the ANL in normal-hearing Mandarin listeners may not be affected by presentation modes such as a loudspeaker or earphones nor is it affected by self-adjusted or audiologist-adjusted response modes. Earphone audiometry is as reliable as sound field audiometry and provides an easy and convenient way to measure ANL.

Mapping speech transmission index (STI) and background noise in university classrooms

2017 ◽  
Vol 141 (5) ◽  
pp. 3481-3481
Author(s):  
Andrew Hulva ◽  
Michael Ermann ◽  
Jeffrey Rynes ◽  
Randall J. Rehfuss ◽  
Aaron Kanapesky ◽  
...  
Keyword(s):  
Background Noise ◽  
Transmission Index ◽  
Speech Transmission ◽  
University Classrooms

scholarly journals Archaeoacoustic Examination of Lazarica Church

Acoustics ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 423-438 ◽  
Author(s):  
Zorana Đorđević ◽  
Dragan Novković ◽  
Uroš Andrić
Keyword(s):  
Speech Intelligibility ◽  
Acoustic Analysis ◽  
Sound Field ◽  
Simulation Software ◽  
Central Dome ◽  
Acoustic Effect ◽  
Additional Information ◽  
Medieval Church ◽  
Transmission Index ◽  
Speech Transmission

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.

scholarly journals An Experimental Study of Acoustic Comfort in Open Space Banks Based on Speech Intelligibility and Noise Annoyance Measures

2017 ◽  
Vol 42 (2) ◽  
pp. 333-345 ◽  
Author(s):  
Rostam Golmohammadi ◽  
Mohsen Aliabadi ◽  
Trifah Nezami
Keyword(s):  
Background Noise ◽  
Speech Intelligibility ◽  
Open Space ◽  
Irrelevant Speech ◽  
Acoustic Properties ◽  
Noise Levels ◽  
Noise Annoyance ◽  
Transmission Index ◽  
Acoustic Comfort ◽  
Bank Employees

Abstract Tasks requiring intensive concentration are more vulnerable to noise than routine tasks. Due to the high mental workload of bank employees, this study aimed to evaluate acoustic comfort in open-space banks based on speech intelligibility and noise annoyance metrics. Acoustic metrics including preferred noise criterion (PNC), speech transmission index (STI), and signal to noise ratio (SNR) were measured in seventeen banks (located in Hamadan, a western province of Iran). For subjective noise annoyance assessments, 100-point noise annoyance scales were completed by bank employees during activities. Based on STI (0.56±0.09) and SNR (20.5±8.2 dB) values, it was found that speech intelligibilities in the workstations of banks were higher than the satisfactory level. However, PNC values in bank spaces were 48.2±5.5 dB, which is higher than the recommended limit value for public spaces. In this regard, 95% of the employees are annoyed by background noise levels. The results show irrelevant speech is the main source of subjective noise annoyance among employees. Loss of concentration is the main consequence of background noise levels for employees. The results confirmed that acoustic properties of bank spaces provide enough speech intelligibility, while staff’s noise annoyance is not acceptable. It can be concluded that due to proximity of workstations in open-space banks, access to very short distraction distance is necessary. Therefore, increasing speech privacy can be prioritised to speech intelligibility. It is recommended that current desk screens are redesigned in order to reduce irrelevant speech between nearby workstations. Staff’s training about acoustic comfort can also manage irrelevant speech characteristics during work time.

Most Comfortable Listening Levels, Background Noise Levels, and Acceptable Noise Levels for Children and Adults with Normal Hearing

2011 ◽  
Vol 22 (05) ◽  
pp. 286-293 ◽  
Author(s):  
Robert Moore ◽  
Susan Gordon-Hickey ◽  
Alisha Jones
Keyword(s):  
Young Adults ◽  
Noise Level ◽  
Background Noise ◽  
Developmental Change ◽  
Pediatric Population ◽  
Strong Predictor ◽  
Normal Hearing ◽  
Noise Levels ◽  
Cross Sectional ◽  
The Difference

Background: For adults the acceptable noise level (ANL) has been shown to be a strong predictor of hearing aid success. ANL is calculated as the difference between most comfortable listening level (MCL) and background noise level (BNL). No studies have made direct comparisons of these measures between adults and children. Purpose: To evaluate and compare MCLs, BNLs, and ANLs in children and young adults. Research Design: A cross-sectional design was used in this study. Two groups (children and adults) were tested for each dependent variable. MCLs and BNLs were measured for each participant, and ANLs were computed from these two measurements. Study Sample: The participants were 34 children (8–10 yr) and 34 young adults (19–29 yr) with normal hearing. Results: Significant main effects were found for MCLs and BNLs. There was no main effect for ANLs. MCLs and BNLs were significantly lower for the children than for the adults. Conclusions: These results suggest that while ANLs are unchanged from childhood to adulthood, there appears to be a developmental change in MCLs and BNLs. These findings have implications for the use of ANLs in the pediatric population.

scholarly journals Penilaian Kondisi Akustik Di Dalam Ruang Kelas Melalui Program Simulasi Odeon 5.0 (Studi Kasus: SMP Negeri 4 Banda Aceh)

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Rosa Mardiana ◽  
Bastian Arifin ◽  
Izarul Machdar
Keyword(s):  
Noise Level ◽  
Educational Institution ◽  
Quality Standards ◽  
Noise Levels ◽  
School Conditions ◽  
Transmission Index ◽  
Speech Transmission ◽  
School Yard ◽  
Noisy Background ◽  
Banda Aceh

School is one of areas that must be controlled by noise level. In accordance with the quality standards of noise level at the school or educational institution is 55 dB. The school conditions polluted air pollution will affect the comfort and ultimately student in learning process and give bad effect for the students’ achievement concentration decreases. The aim of the research is to analyze noise level and see composite materials to reduce noise levels through computer simulation approach. Parameter acoustic test in the noisy background (Background of Noise), Sound Pressure Level Distribution, Time buzz, Speech Transmission Index (STI) and Insulation. The sample of this research is in SMPN 4 Banda Aceh. Based on the data obtained, it is found that the noise levels at the site beyond the expiry of the quality standards required that at one point in the school yard around 76.8 dB, point 2 in classrooms around 66.1 dB and point 3 outside of school grounds around 77.7 dB. Based on simulation results for Clarity / C80 superior to the material to 3, for reverberation time and decay (D50 and T30) superior to the material to 4th and 5th, while for clarity conversation / STI all the ingredients fit in either category.

Masking of Speech in Young and Elderly Listeners With Hearing Loss

1994 ◽  
Vol 37 (3) ◽  
pp. 655-661 ◽  
Author(s):  
Pamela E. Souza ◽  
Christopher W. Turner
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Sensorineural Hearing Loss ◽  
Background Noise ◽  
Normal Hearing ◽  
Sensorineural Hearing ◽  
Masking Noise ◽  
Speech Spectrum ◽  
Specific Factors ◽  
High Pass

This study examined the contributions of various properties of background noise to the speech recognition difficulties experienced by young and elderly listeners with hearing loss. Three groups of subjects participated: young listeners with normal hearing, young listeners with sensorineural hearing loss, and elderly listeners with sensorineural hearing loss. Sensitivity thresholds up to 4000 Hz of the young and elderly groups of listeners with hearing loss were closely matched, and a high-pass masking noise was added to minimize the contributions of high-frequency (above 4000 Hz) thresholds, which were not closely matched. Speech recognition scores for monosyllables were obtained in the high-pass noise alone and in three noise backgrounds. The latter consisted of high-pass noise plus one of three maskers: speechspectrum noise, speech-spectrum noise temporally modulated by the envelope of multi-talker babble, and multi-talker babble. For all conditions, the groups with hearing impairment consistently scored lower than the group with normal hearing. Although there was a trend toward poorer speech-recognition scores as the masker condition more closely resembled the speech babble, the effect of masker condition was not statistically significant. There was no interaction between group and condition, implying that listeners with normal hearing and listeners with hearing loss are affected similarly by the type of background noise when the long-term spectrum of the masker is held constant. A significant effect of age was not observed. In addition, masked thresholds for pure tones in the presence of the speech-spectrum masker were not different for the young and elderly listeners with hearing loss. These results suggest that, for both steady-state and modulated background noises, difficulties in speech recognition for monosyllables are due primarily, and perhaps exclusively, to the presence of sensorineural hearing loss itself, and not to age-specific factors.

Aircraft interior acoustics - background noise contamination

2021 ◽  
Vol 263 (5) ◽  
pp. 1606-1619
Author(s):  
Ramana Kappagantu ◽  
Manuel Etchessahar ◽  
Edgar Matas ◽  
Koen Vansant
Keyword(s):  
High Frequency ◽  
Background Noise ◽  
Noise Source ◽  
Operating Conditions ◽  
Low Frequencies ◽  
Acoustic Design ◽  
Points Of Interest ◽  
Transmission Index ◽  
Speech Transmission ◽  
Noise Contamination

Aircraft interior noise is an important factor to be considered for cabin comfort. In a cruising condition this noise source is mostly broadband in nature and is coming from the exterior, primarily the turbulent boundary layer (TBL) of the flow around the moving aircraft. Capturing this noise to a high frequency is critical for designing the sound packaging. Also, this becomes important in the design of public announcement (PA) system for the aircraft cabin, i.e. the correct placement of speakers. One of the metrics used for this acoustic design is speech transmission index. Deterministic techniques like finite or boundary element techniques for low frequencies and ray tracing method to reach higher frequencies are better suited for getting the narrow band responses. On the other hand, to characterize the background noise due to the TBL loads, statistical energy analysis (SEA) route is pursued. In this paper the authors combine different techniques to capture the background noise and use them with PA sources and eventually capture the sound perceived at points of interest. The articulation metrics are compared for different operating conditions of the aircraft. In the presentation attempts will be made to play the auralized sounds.

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