Peculiarities of a Rarely Used Method of Measuring the Speech Transmission Index in Premises
Abstract - 62


Test signal
STITEL method
measurement error
Speech intelligibility
Speech transmission index

How to Cite

Prodeus A, Naida A, Dvornyk O, Didkovska M. Peculiarities of a Rarely Used Method of Measuring the Speech Transmission Index in Premises. Int. J. Archit. Eng. Technol. [Internet]. 2023 Dec. 20 [cited 2024 Feb. 22];10:30-9. Available from:


Evaluation of speech transmission index (STI) in premises allows for determining the speech intelligibility, and therefore the suitability of premises for speech communication. STI measurements using the speech transmission index for telecommunication systems (STITEL) method are rarely performed in rooms, possibly due to insufficient information on the accuracy of this method. In this paper, computer simulations were used to estimate the STI estimation errors by the STITEL method under conditions of noise and reverberation. The pink noise model and the room impulse response estimate of a real room with a reverberation time T60=0.8 s were used for the research. The duration of the test signals varied between 4, 8, 16, 32, and 64 seconds, and the signal-to-noise ratio varied from minus 28 dB to plus 28 dB. The dependences of the bias, standard deviation, and total error of the STI estimate on the duration of the test signal and the signal-to-noise ratio are obtained. It is shown that the total error of the STI estimation is close to 0.03 when the duration of the test signal is 8 s. Under conditions of noise action, this error decreases with a further increase in the duration of the test signal. Under conditions of joint action of noise and reverberation, such a decrease was not observed, while the total error is within 0.03-0.04.


Jacob K. Correlation of speech intelligibility tests in reverberant rooms with tree predictive algorithms. J Audio Eng Soc. 1989; 37: 1020-30.

Jacob K. Understanding speech intelligibility and the fire alarm code. NFPA World Safety Congress, Anaheim, CA: 2001.

Grant C. Intelligibility of fire alarm and emergency communication systems, final report. The Fire Protection Research Foundation; Quincy, MA, USA: 2008.

Bradley JS, Reich RD, Norcross SG. On the combined effects of signal-to-noise ratio and room acoustics on speech intelligibility. J Acoust Soc Am. 1999; 106: 1820-8.

Sato H, Bradley JS. Evaluation of acoustical conditions for speech communication in working elementary school classrooms. J Acoust Soc Am. 2008; 123: 2064-77.

Bradley J, Sato H. Speech intelligibility test results for grades 1, 3 and 6 children in real classrooms. Proceedings of the 18th Int Congress on Acoustics, Kyoto: Semantic Scholar; 2004.

Yang W, Bradley JS. Effects of room acoustics on the intelligibility of speech in classrooms for young children. J Acoust Soc Am. 2009; 125: 922-33.

Youssef SR, Bard D, Mahmoud AEFA, Esa NM. Acoustical quality assessment of lecture halls at Lund University, Sweden. Proc. 43rd International Congress and Exposition on Noise Control Engineering, Melburn: 2014.

Eggenschwiler K. Lecture halls - Room acoustics and sound reinforcement. 4th European Congress on Acustics, Budapest: Forum Acusticum; 2005.

DiMarino C, Fuerth D, Gignac D, Lunardi A, Novak C, Pikul R, et al. Acoustic enhancement of proposed grand lecture hall using computer simulation. Can Acoust. 2011; 39: 43-8.

British Standard BS EN 60268-16. Sound system equipment– Part 16: Objective rating of speech intelligibility by speech transmission index; 26 August 2011 (withdrawn on 2 August 2014).

Möller H. A Review of STI Measurements; Proceedings of the Forum Acusticum; Lyon, France. 7-11 December 2020; pp. 173-6.

Wijngaarden S, Verhave J. Speech intelligibility measurements in practice; Obtaining accurate and reliable data using STIPA tools. Embedded Acoustics BV; 2014.

Wijngaarden S, Verhave J. Recent advances in STI measuring techniques. In: Proceedings of the Institute of Acoustics, vol. 28, 2006.

Zhu P, Tao W, Mo F, Guo F, Lu X, Liu X. Experimental comparison of speech transmission index measurement in natural sound rooms and auditoria. Appl Acoustics. 2020; 165: 107326.

Zhu P, Mo F, Kang J. Experimental comparison between direct and indirect measurement methods for the objective rating of speech intelligibility. Proc. 21st International Congress on Sound and Vibration, Beijing, China: 13-17 July, 2014.

Kotus J, Kostek B, Kurowski A, Szczuko P. A comparison of STI measured by direct and indirect methods for interiors coupled with sound reinforcement systems. In: 2018 Joint Conference - Acoustics, Ustka: IEEE; 2018, p. 1-6.

D’Orazio D, Rossi E, Garai M. Comparison of different in situ measurements techniques of intelligibility in an open-plan office. Building Acoustics. 2018; 25: 111-22.

Application Note. Measuring speech intelligibility using DIRAC - Type 7841. Brüel & Kjær 2013. Available from: (Accessed August 12, 2023).

Acoustics Engineering. Technical note TN008 "DIRAC stimuli 2008. Available from: (Accessed August 12, 2023).

Farina A. User Manual of Aurora 4.3, Parma (Italy). 2012.

Ponteggia D. Speech intelligibility assessment using CLIO 11. Application note AN-013. Available from (Accessed on August 12, 2023).

Application note. Speech Intelligibility. Measurement with the XL2 Analyzer 2020. NTi Audio. Available from (Accessed on August 12, 2023).

Jeub M, Schafer M, Vary P. A binaural room impulse response database for the evaluation of dereverberation algorithms. In International Conference Proceedings on Digital Signal Processing (DSP), Santorini: IEEE; 2009, p. 1-5.

Harasiuk AO, Myronov MV, Lozinsky VV, Thanh Vy N, Darchuk AV, Prodeus AM. Predictive estimation of speech intelligibility masked by noise interference. Microsystems, Electronics and Acoustics. 2019; 24: 48-55.

Bradley JS, Reich R, Norcross SG. A just noticeable difference in C 50 for speech. Appl Acoustics. 1999; 58: 99-108.

Byrne D, Dillon H, Tran K. An international comparison of long-term average speech spectra. J Acoust Soc Am. 1994; 96: 2108-20.

Morales L, Leembruggen G, Dance S, Shield BM. A revised speech spectrum for STI calculations. Appl Acoustics. 2018; 132: 33-42.

Pedchenko O, Lunova S. Analysis of ukrainian diagnostic articulation tables. EUREKA: Phys Eng. 2018; 1: 63-72.

Naida S, Didkovskyi V, Pavlenko O, Naida N. Spectral analysis of sounds by acoustic hearing analyzer. 2019 IEEE 39th International Conference on Electronics and Nanotechnology (ELNANO), Kyiv: IEEE; 2019, p. 421–4.

Mahmoud DS, El-Sabbagh SH, El-Basheer TM, Moustafa A, Barakat MA. Rheometeric, ultrasonic and acoustical shielding properties of Cu-alloy/silicone rubber composites for electronic applications. J Thermoplast Compos Mater. 2023; 36: 4684–706.

Tarek M, El-Basheer. The acoustic characteristics of religious buildings. Int J Archit Eng Technol. 2022; 9: 71-2.

Elkhateeb A, Eldakdoky S. The optimal reverberation for masjids. Int J Archit Eng Technol. 2022; 9: 73-99.

Siegfried L. The magic in 2-Channel sound reproduction - Why is it so Rarely Heard? Int J Archit Eng Technol. 2015; 2: 113-26.

Prodeus A, Didkovska M, Kukharicheva K. Comparison of speech quality and intelligibility assessments in university classrooms. Int J Archit Eng Technol. 2021; 8: 52-60.

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Copyright (c) 2023 Arkadiy Prodeus, Anton Naida, Oleksandr Dvornyk, Maryna Didkovska


Download data is not yet available.