Artificial Software Complex "Artificial Head". Part 2 Evaluation of Speech Intelligibility in Classrooms
Article Sidebar
Main Article Content
Abstract
Experimental studies of the use of the developed hardware and software tool “Artificial Head” for two-channel estimation of the intelligibility of the speech distorted by reverberation have been performed in this paper. The peculiarity of this complex is that it contains electro-acoustic equipment of different quality, including household appliances with mediocre quality features.
In the first stage of this evaluation, the response of the room to the test signal is recorded. The test signal was based on the maximum-length sequence (mls) which is a periodic two-level signal of length 216, which corresponds to a signal length of 1.49 s at a sampling rate of 44.1 kHz. This mls-sequence was repeated 17 times during radiation and averaging the last 16 bursts of the cross-correlation estimates have been made to increase the signal-to-noise ratio by 12 dB in the calculation of the room impulse response.
The calculation of the cross-correlation function of the response and the test signal was performed in the second stage, while the correction of the frequency characteristic of the measuring path was performed by it dividing by the amplitude-frequency characteristic of the loudspeaker-microphone subsystem. To improve the accuracy of the calculations, the result of such division was multiplied by the regularization factor in the form of a Hann window.
In the third stage, the modulation coefficients were calculated according to the Schroeder formula, using the room impulse response estimate. In the fourth, last step, speech intelligibility was evaluated by a modulation or formant-modulation method.
The results of the speech intelligibility evaluation in two lecture rooms of small and medium size showed that the speech intelligibility in the middle of the room can be less than that near the wall of the room. These results are in line with the results of previous studies, where speech intelligibility has been evaluated by objective and subjective methods for another lecture room. It should be noted that although the estimates of the widely used C50 coefficient are consistent with the estimates of speech intelligibility, the phenomenon of increasing speech intelligibility near the walls of the room is more pronounced when applying the speech intelligibility estimates.
The results presented in this paper indicate that the usefulness of early reflections in the room is different in different parts of the room. This important fact must be taken into account both in the design and the reconstruction of the lecture rooms.
Article Details
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
References
O. O. Dvornyk, D. I. Motorniuk, M. V. Didkovska, and A. M. Prodeus, “Artificial Software Complex ‘Artificial Head’. Part 1 Adjusting the Frequency Response of the Path,” Microsystems, Electron. Acoust., vol. 25, no. 1, pp. 56–64, Jul. 2020, DOI: 10.20535/2523-4455.mea.198431.
J. Blauert, Ed., The Technology of Binaural Listening. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013, ISBN: 978-3-642-37761-7.
“HEAD acoustics - Telecom Division - Binaural Recording Systems - Artificial Head Measurement System HMS II.3 - Overview.” [Online]. Available: https://www.head-acoustics.com/eng/telecom_hms_II_3.htm. [Accessed: 23-Mar-2020].
P. L. SØndergaard and P. Majdak, “The auditory modeling toolbox,” in The Technology of Binaural Listening, Springer Berlin Heidelberg, 2013, pp. 33–56.
M. Jeub, M. Schafer, and P. Vary, “A binaural room impulse response database for the evaluation of dereverberation algorithms,” in 2009 16th International Conference on Digital Signal Processing, 2009, pp. 1–5, DOI: 10.1109/ICDSP.2009.5201259.
“IKS: Aachen Impulse Response Database.” [Online]. Available: https://www.iks.rwth-aachen.de/en/research/tools-downloads/databases/aachen-impulse-response-database/. [Accessed: 23-Mar-2020].
Y. S. Kostyuchok, L. S. Martynovych, D. Y. Motorniuk, V. O. Nechytailo, A. V. Hrapachevskiy, and A. M. Prodeus, “Acoustic certification of classrooms,” Electron. Commun., vol. 21, no. 2, pp. 63–70, Nov. 2016, DOI: 10.20535/2312-1807.2016.21.2.82217.
“SOUND FORGE Audio Studio 14 – Домашняя студия редактирования звука.” [Online]. Available: https://www.magix.com/ru/muzyka/sound-forge/sound-forge-audio-studio/. [Accessed: 23-Mar-2020].
A. Prodeus, V. Didkovskyi, M. Didkovska, I. Kotvytskyi, and D. Motorniuk, “Automated Subjective Assessment of Speech Intelligibility Under Diotic and Dichotic Listening,” in Data-Centric Business and Applications, Springer, Cham, 2020, pp. 1–16, URL: http://link.springer.com/10.1007/978-3-030-43070-2_1. DOI: 10.1007/978-3-030-43070-2_1
E. A. P. Habets, N. D. Gaubitch, and P. A. Naylor, “Temporal selective dereverberation of noisy speech using one microphone,” in 2008 IEEE International Conference on Acoustics, Speech and Signal Processing, 2008, pp. 4577–4580, DOI: 10.1109/ICASSP.2008.4518675.
G. A. Soulodre, N. Popplewell, and J. S. Bradley, “Combined effects of early reflections and background noise on speech intelligibility,” J. Sound Vib., vol. 135, no. 1, pp. 123–133, Nov. 1989, DOI: 10.1016/0022-460X(89)90759-1.
J. S. Bradley, H. Sato, and M. Picard, “On the importance of early reflections for speech in rooms,” J. Acoust. Soc. Am., vol. 113, no. 6, p. 3233, 2003, DOI: 10.1121/1.1570439.
I. Arweiler, J. Buchholz, and T. Dau, “Speech intelligibility enhancement by early reflections | Proceedings of the International Symposium on Auditory and Audiological Research,” in Speech processing and perception under adverse conditions, 2009, pp. 289–298, URL: https://proceedings.isaar.eu/index.php/isaarproc/article/view/2009-29.
H. Sato and J. S. Bradley, “Evaluation of acoustical conditions for speech communication in working elementary school classrooms,” J. Acoust. Soc. Am., vol. 123, no. 4, pp. 2064–2077, 2008, DOI: 10.1121/1.2839283.
V. S. Didkovskyi, M. V. Didkovskaya, and A. M. Prodeus, Komp’yuterna obrobka akustychnykh syhnaliv. Navchalʹnyy posibnyk. [Computer processing of acoustic signals. Tutorial.]. Kyiv: Imecs-LTD, 2010.
A. N. Tikhonov, “O nekorrektnykh zadachakh lineynoy algebry i ustoychivom metode ikh resheniya [On ill-posed problems of linear algebra and a stable method for solving them],” DAN USSR, vol. 163, no. 3, pp. 591–594, 1965.
H. J. M. Steeneken and T. Houtgast, “A physical method for measuring speech‐transmission quality,” J. Acoust. Soc. Am., vol. 67, no. 1, pp. 318–326, 1980, DOI: 10.1121/1.384464.
H. J. . Steeneken and T. Houtgast, “Validation of the revised STIr method,” Speech Commun., vol. 38, no. 3–4, pp. 413–425, Nov. 2002, DOI: 10.1016/S0167-6393(02)00010-9.
A. M. Prodeus, L. B. Dronzhevskaya, V. A. Klimkov, and D. A. Shagitova, “Formantnyy i formantno-modulyatsionnyy metody otsenki razborchivosti rechi. Chast’ 1. Unifikatsiya algoritmov,” Electron. Commun., vol. 15, no. 6 (part 2), pp. 117–124, 2010.
A. N. Prodeus, L. B. Dronzhevskaya, V. A. Klimkov, and D. A. Shagitova, “Formantnyy i formantno-modulyatsionnyy metody otsenki razborchivosti rechi. Chast’ 2. Tochnost’ i skorost’ izmereniy [Formant and formant-modulation methods for assessing speech intelligibility. Part 2. Accuracy and speed of measurements.],” Electron. Commun., vol. 16, no. 6, pp. 16–24, 2011.
M. R. Schroeder, “Modulation Transfer Functions: Definition and Measurement,” Acta Acust. united with Acust., vol. 49, no. 3, pp. 79-182(4), 1981, URL: https://www.ingentaconnect.com/content/dav/aaua/1981/00000049/00000003/art00004?crawler=true&mimetype=application/pdf.
N. B. Pokrovskiy, Raschet i izmerenie razborchivosti rechi [Prediction and measurement of speech intelligibility]. Moskow, USSR: Svyazizdat, 1962.
M. A. Sapozhkov, Rechevoy signal v kibernetike i svyazi [Speech signal in cybernetics and communication]. Moscow: Svyazizdat, 1963.
A. M. Prodeus, V. S. Didkovskyi, and M. V. Didkovskaya, Akusticheskaya ekspertiza i korrektsiya kommunikatsionnykh kanalov [Acoustic examination and correction of communication channels]. LAP LAMBERT Academic Publishing, 2017, ISBN: 978-3-330-04591-0.
V. E. Gantmakher, N. E. Bystrov, and D. V. Chebotarev, Shumopodobnyye signaly. Analiz, sintez, obrabotka [Noise-like signals. Analysis, synthesis, processing]. St. Peterburg: Nauka i tekhnika, 2005.
M. R. Schroeder, “New Method of Measuring Reverberation Time,” J. Acoust. Soc. Am., vol. 37, no. 6, pp. 1187–1188, Jun. 1965, DOI: 10.1121/1.1939454.
U. Zölzer, Ed., DAFX: Digital Acoustic Effects, 2nd ed. John Wiley & Sons, 2011, ISBN: 978-0-470-66599-2.
