Acoustic Comfort in Hybrid Learning Spaces: Students Perspective Hussein M. Elmehdi 1

Department of Applied Physics and Astronomy University of Sharjah Sharjah United Arab Emirates Ania Tato Iglesias 2 University of the Basque Country Bilbao, Spain

ABSTRACT Acoustic comfort in classrooms has a great impact on the quality of education. In specific, its impact on teaching and learning experience has been widely studied and the results show that acoustic comfort is linked to learning attributes, e.g. enhancing productivity, memorizing and understanding of the taught material, mental welfare, and motivation. In this paper, we assess the acoustic comfort in hybrid classrooms, at the University of Sharjah, after classes have been reconfigured to comply with COVID-19 social distancing protocols. First, we measured the background noise and reverberation times for different types of classrooms used for teaching and learning. The results showed that most classrooms do not comply with international standards. For example, the background noise levels in the selected classrooms were found to range from 43.9 – 49.6 dB(A), which is higher than the recommended WHO limits. To evaluate the acoustic comfort from the perspective of the students, a survey was conducted to evaluate students’ perception on acoustic conditions at the hybrid classrooms. The results showed that the majority of the students surveyed, 88%, felt that noise in classrooms affected their understanding of the material and communications with the instructor and peers. Noise sources were identified to originate from corridors, maintenance work, and construction sites within close proximity to the classrooms. Better designs are highly recommended to improve acoustic comfort to ensure an excellent student experience and the best learning environment.

1. INTRODUCTION

After the COVID-19 regulations and measures were relaxed in the summer of the 20/21, academic year, institutions were allowed to conduct classes in on campus albeit in accordance with the COVID- 19 regulations that included social distancing. The latter imposed further restrictions on the classroom’s setup and capacities, which was reduced to 50% its regular capacity. This means that the

1 hmelmehdi@sharjah.ac.ae

2 Tato.ania20@gmail.com

number of chairs (or desks) were reduced in each classroom, which is known to have an impact of the acoustic quality of the classrooms. Previous studies, including ours [1,2] have focused on assessing the acoustic quality of regular classrooms (i.e., pre COVID-19). While the impact on acoustic parameters can be easily measured through careful measurements of acoustics quality indicators, students’ perception is not straight forward to assess since it depends on many factors. One common approach is to conduct a subjective survey comprised of well-designed set of questions aimed at gauging students’ perception based on relevant acoustic quality information.

In general, enhancing educational processes, improving the quality of education through increasing the attention of students (comfort) is linked to the design of learning facilities and spaces. The task is considered multidisciplinary in nature and needs the consideration of many factors, including lightning, room temperature, design and acoustic conditions, which is considered the most important factor among all [1]. The effect of acoustic conditions of the learning spaces on teachers' and students' performance is remarkable. Poor acoustics are known to impair comprehension of the taught material, diminish concentration, and provoke psychological and physical disorders resulting in the deterioration of productivity, both for teachers and students [2].

Background noise, signal-to-noise ratio, and reverberation time have been identified by The World Health Organization (WHO) as the main factors impacting acoustic comfort [3]. WHO recommends the background noise of less than 35 dBA and a reverberation time between 0.4 s and 1.2 s for classrooms’ acoustic comfort. Our aim in this project is to determine students' perception of the acoustic conditions in hybrid classrooms at the University of Sharjah (UoS), which were implemented as a measurement to comply with the COVID-19 restrictions, which included the reduction the number of seats in the classroom in accordance to the social distancing protocols. The hybrid approach allows a fraction (about 40%) of the students to attend the classes in person, whereas the others attend classes concurrently online via videoconference platforms such as Zoom, MS Teams and Blackboard Collaborate. Our study relies on a carefully designed survey that was emailed to students taking courses in the selected hybrid classrooms, chosen to represent the four types of lecture halls used in the University. The survey was designed to gauge students' perception, insight and evaluation of the acoustic quality of the learning environment within the University. In addition, the survey ask students to evaluate the impact of noise on communication, learning activities, and comprehension of the taught material within the classroom. The results were correlated with the onsite measurements of the background noise levels and reverberation times taken in the selected hybrid classrooms, which were conducted following international protocols. Therefore, the current research finding will be the first (according to the author’s knowledge) to gauge students’ perception on acoustic quality (or comfort) in hybrid classrooms. 2. METHODOLOGY

2.1. Description of the selected classrooms and acoustic measurements

The classrooms assessed in this study were selected to represent the various classroom types used for lectures at the UOS and are shown in Figure 1. Their characteristics are summarized in Table 1. In the questionnaire, the classroom W10-007 corresponds to the theatre type classrooms, W10-004 and W10-110 are designated as middle size classrooms and W10-111 is a small size classroom.

Table 1: Room characteristics

W10-007 W10-004 W10-110 W10-111 Surface area 507 m2 322 m2 326 m2 232 m2 Volume 526 m3 352 m3 303 m3 200 m3 No. of seats 47 40 41 30 Acoustic treatment Absorbent ceiling

The measurements were performed in empty occupancy conditions, except for an operator required for the measurement recording. The background noise was measured with a NOR140 Sound Analyzer (Norsonic AS, Norway) calibrated with the help of a Castle GA601 Single Level Class 2 Sound Meter Calibrator (Castle GROUP, UK) with an accuracy of ±0.1 dB for the equivalent sound pressure level. The measurements were carried out for three minutes in three different positions (front, middle, and back part of the classroom) and the results were averaged. Reverberation time measurements were carried out following the guidance of ISO 3382-2. We used the integrated impulse response method with engineering precision. As a sound source, we used a non-omnidirectional speaker BX5 D3 5” Powered Studio Reference Monitor (M-audio, USA), which is consistent with ISO 3382-2. The microphone employed in these experiments was an omnidirectional Behringer UltraLinear Measurement Condenser Microphone ECM8000 (Behringer, Germany). The speaker and the microphone were connected to a portable computer via Steinberg UR12 (Steinberg Media Technologies GmbH, Germany) audio interface. Both speaker and microphone were positioned 1.5 m above the ground and the distance between them was always greater than 1.5 m, in compliance with ISO 3382-2 requirements. The data was acquired using the software ROOM EQ Wizard (REW).

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Figure 1: classrooms a) W10-007, b) W10-004, c) W10-110 and W10-111.

2.2. Acoustic survey

The survey comprised twenty-four questions subdivided into three sections, the first of which contained eight questions regarding demographic information such as gender and age. In addition, students were asked about their hearing and socio-acoustic status. The second section of the survey consisted of questions designed to students to evaluate the acoustic conditions of the hybrid classrooms using fifteen unipolar Likert type scale descriptive adjectives used to describe the acoustic condition, quality and comfort within the learning environment at the University of Sharjah. Students were also asked to state how pleased they were with the University's sound environment as a whole. The last section of the survey aimed at identifying noise sources contributing to the noise levels within the learning environment. Students were asked to evaluate specific noise sources, to state the duration and frequency of the sounds they heard during the lectures, and to indicate their perception of them. This is of paramount importance for correlating responses to onsite measurements and for the assessment of acoustic parameters and noise level indicators. The impact of noise on teaching and

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learning attributes was also formulated in direct and indirect questions. These included ranking, Likert-type questions (with ranks of 4 levels or 10 levels, depending on the question), and multiple- choice questions. The survey was benchmarked against several published studies to allow comparison and validation [1, 4, 5]. The survey was constructed using Microsoft Forms and distributed to the students taking classes in hybrid classrooms via email by the Information Technology Center at the UoS. Survey questions were presented in English and Arabic. Students were informed via a brief introductory paragraph of the purpose of the survey (research and development), the total time expected to take it as well as a thank you and appreciation message. 3. RESULTS AND DISCUSSION

3.1. Acoustic measurements

The results for the background noise are summarized in Table 2. As listed here, the background noise levels in three of the four selected classrooms are not within most international standards. This is consistent with other widely reported results as most of the teaching centers present high levels of background noise [1,2]. The classroom W10-111 has a lower background noise because the air conditioning system was off during the acoustic measurements. The reverberation times, i.e T20 (the reverberation time for the band's central frequency), in octave bands from the 125 Hz band to the 4 kHz band for the four selected classrooms are represented in Figure 2. It can be seen that none of the classrooms comply with international standards. Nevertheless, the measured values mostly agree with the reported in the literature for similar classrooms [6]. It is also clear from this figure that the classrooms on the ground floor (W10-007 and W10-004) have larger reverberation times than the classrooms on the first floor (W10-110 and W10-111) for all the measured frequencies. This could be due to structural differences between the classrooms such as the wall configuration or the junctions to other building elements.

Table 2: Mean and standard deviation for the background noise in the analyzed classrooms.

L eq (dBA) W10-007 50.9 ± 0.7 W10-004 47.4 ± 0.4 W10-110 43.0 ± 0.9 W10-111 32.3± 0.3

Figure 2: reverberation times T20 for the selected frequencies in every classroom

Revrebration Time (s) ‘ te, 3 . 0 ‘500 1000” 1800” 2000” 2600 3000” 3600” 40004500 Frquency (Hz)

3.2. Acoustic survey

As stated above, the survey was emailed to students taking courses in the UoS hybrid classrooms. The number of respondents was n=492, from which 78% were female and 22% were male, distributed among thirteen university colleges. The majority of the respondents (74%) were between 18 and 24 years old, as expected. 65% of the surveyed indicated that the lectures are not taught in their native language and the remaining ones indicated the contrary. Only 4% of the students reported to have hearing problems. Besides, most of the respondents indicated that their sensitivity to sound is not high with 31% pointing that they are not sensitive at all, 38% that they are somewhat sensitive and only 2% stating that they are extremely sensitive. The rest reported their sensitivity being somewhere between fairly sensitive and very sensitive. Respondents were also asked to identify adjectives that accurately describe the sound environment and the results show that in general students are satisfied with the acoustic atmosphere. Students were asked which classrooms they take most of their classes at and which ones were perceived as the noisiest. The theatres were identified as the noisiest among the lecture halls used as hybrid classrooms. The result is expected since the dimensions of the theatres are the greatest with half of the furniture removed as required by Covid-19 protocols. The results are consistent with previous work prior to Covid-19 and are in agreement with the measured background noise, as the highest levels (almost 50 dBA) were recorded in the theatre type classroom W10-007 [2,5]. There is weak correlation between the reverberation time and the acoustic comfort in the classrooms. The reverberation times of the classrooms W10-110 (classified as middle size) and W10- 111 (referred to as small size) are alike and so is the perception of the noise in them, as 21% of the respondents selected the former type as the noisiest whereas 19% selected the latter. However, although classrooms W10-007 and W10-004 also have similar reverberation times, 60% of the students indicated that the theatres are noisier. Students were asked to identify the cause for the acoustic discomfort during the courses among 7 noise sources. The results show that the main source of unease is noise occurring outside of the classrooms. This includes noises in the corridors and lobbies as well as other noise sources. The second of acoustic discomfort is the instructor's voice, as 18% of the surveyed reported it to be not clear or not loud enough. This may be due to the high reverberation times in the classrooms which could distort the speech masking the lower level consonants [7]. We also found that noise originating from the corridor is the most often heard noise during the classes. Besides, the students stated that noisy environments in the classroom require an extra effort for them to stay focused. The last questions focused on gauging students’ overall satisfaction with the acoustic environment within the classrooms. Respondents were asked to evaluate acoustic comfort inside the classrooms and the outcome indicated that the students are fairly neutral, although there are more detractors than promoters. This means that even if students are not in great discomfort with the acoustic characteristic of the classrooms, these can be enhanced. 4. CONCLUSIONS

Overall, the performed measurements allow us to conclude that background noise conditions and the reverberation times in the classrooms do not comply with international standards. As a reflection of this reality, students' have classified the classrooms at the University of Sharjah to be noisy and the instructor's voice to be not clear or not loud enough. Among the noise sources, corridor noise and construction or maintenance work from the near classrooms and from outside the University have been stated as the noisiest. The correlation between the students' acoustic satisfaction and the measured acoustic parameters is not strong although acoustic satisfaction seems to decrease with increasing reverberation time and background noise. These results are in agreement with previous studies of acoustic comfort in the University of Sharjah [2,5].

4. CONCLUSIONS

Overall, the performed measurements allow us to conclude that background noise conditions and the reverberation times in the classrooms do not comply with international standards. As a reflection of this reality, students' have classified the classrooms at the University of Sharjah to be noisy and the instructor's voice to be not clear or not loud enough. Among the noise sources, corridor noise and construction or maintenance work from the near classrooms and from outside the University have been stated as the noisiest. The correlation between the students' acoustic satisfaction and the measured acoustic parameters is not strong although acoustic satisfaction seems to decrease with increasing reverberation time and background noise. These results are in agreement with previous studies of acoustic comfort in the University of Sharjah [2,5]. 5. ACKNOWLEDGEMENTS

The authors are very grateful to the Vice Chancellor Office for Research and Graduate Studies and the International Association for the Exchange of Students (IAESTE) for partially funding the research project. We are also gratefully thank the Career Advising and Student Training Office at the University of Sharjah for providing logistics for IAESTE Internship. 6. REFERENCES

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