1,721,000 research outputs found
Indoor soundscape in primary school classrooms
No full textSoundscape research on indoor environments is emerging as a topic to be addressed for the design of supportive, healthier, and more comfortable spaces. Only a few studies so far addressed the context of educational buildings, mainly focusing on high schools and universities. This pilot study uses questionnaires based on pictorial scales to investigate the indoor soundscape of classrooms for primary school children (n = 130; 8-10 years old). Perceived loudness and the affective dimensions of pleasantness and arousal were explored. Besides the actual soundscape, the children's ideal soundscape was investigated as well. The results of the study indicate that the most frequent sounds in classrooms are generated by the students themselves (voices, movements) followed by the traffic. The urban context of the school modulates the children's perception when windows are open to ensure natural ventilation. Pleasantness is associated with students' age, perceived loudness, and frequency of children's voices in nearby classrooms. The frequency of hearing indoor sounds (children's voices) and sirens affects students' arousal. Our results indicate that children at school are mostly exposed to unpleasant sounds, whereas their preferred ones are music and nature-related ones. The findings have implications for the design of positive and inclusive learning environments
Listening efficiency in university classrooms: a comparison between native and non-native listeners
No full textWhen listening to speech in one’s native language a higher intelligibility is expected than when listening in a second language: perceptual and linguistic cues readily available for native listeners may be only partly accessed by non-native ones. In this study, the effects of different types of background noises on speech reception performance are compared between native and non-native listeners. Diagnostic Rhyme Tests (DRT) in the Italian language were proposed inside a university classroom of 198 m3, with a reverberation time in occupied conditions of 0.6 s, complying with the target value suggested by the German DIN18041 standard. A group of 26 normal-hearing young adults participated in the experiment: half of them native (Italian), the other half non-native (German) speakers. Listeners’ performance was assessed in three acoustic conditions (ventilation system, stationary, and fluctuating maskers) collecting data on speech intelligibility and response time. The interplay of perceptual and cognitive process in the speech reception process was then described by using the combined metric of listening efficiency
Comparison between simulated and in-situ measured speech intelligibility in the multilingual context of the Free University of Bozen-Bolzano
No full textClassrooms acoustics can affect students ́ speech intelligibility and learning performance depending on its background noise level and/or reverberation. Speech intelligibility is usually assessed in real classrooms through a subjective approach, by performing speech intelligibility tests, or through an objective approach, by evaluating speech transmission index (STI) from impulse response, speech and noise level measurements. Acoustic simulation technique makes it possible to assess acoustical conditions for speech reception in virtual environments, thus allowing for predicting intelligibility before a classroom is built or renovated. However, in order to obtain reliable results, the simulation model needs to be calibrated and validated with in-situ measurements.
The aim of this work is to compare tests performed in-situ on a group of people, with tests performed on the same people by reproducing the auralized test signal through headphones, in terms of intelligibility scores (IS), response times (RT), listening efficiency values (DE) and related STI values.
Simulations have been carried out using the room acoustic software Odeon version 14.01.
The investigation focused on a university classroom, which is part of the Classroom Spaces Living Lab of the Free University of Bozen-Bolzano, currently equipped with devices for monitoring energy and indoor comfort conditions, as well as detailed external weather conditions. By exploiting the bilingual context in South Tyrol, Diagnostic Rhyme Tests (DRT) in the Italian language were administered to both Italian and German native speaker students, the latter with an Italian level at least equal to B2, according to the common European framework of reference for languages. In this way, speech reception performance of the two groups has been investigated and compared
Soundscape and indoor air quality in naturally ventilated educational environments: a multi-domain study
No full textIn this study, indoor air quality (IAQ) and acoustics were jointly analysed to determine their i) combined effect on students' performance in a math task, and ii) cross-modal effect on soundscape perception. 192 students (12 to 14 years) took part in a laboratory experiment. Students were separated into two classroom-like chambers with different IAQ conditions: a CO2 concentration of 800 and 2000 ppm, respectively. The participants were asked to solve calculations and answer a soundscape questionnaire in three listening conditions: quiet, a natural scenario with birdsongs, and one scenario with children's playground activity sounds. In the latter two conditions, the sounds were played back through headphones at a level of 47 dBA. Results show that students had faster response times in the math task in quiet compared to the listening condition with children's activity sounds, while maintaining a similar task accuracy. No effect of the IAQ conditions and natural sounds was found on the task performance. No cross-modal effect of CO2 concentration on soundscape perception was detected. Regarding soundscape assessments, playground activity was rated as the most annoying listening condition, while listening to birdsongs was the most pleasant one, despite its noise level exceeding the quiet condition
Combined effects of environmental factors on human perception and objective performance: A review of experimental laboratory works
No full textThis study reports the outcomes of a literature survey aimed at exploring how different environmental factors-that is acoustic, thermal, visual, and air quality stimuli-interact in affecting building occupants' perception and performance. Recent laboratory studies have been collected, and their methodological approaches reviewed in terms of experimental design, adopted exposures conditions, perception and performance assessment methods. Results have been summarized and compared to identify interaction patterns between environmental factors and possible practical implications for improving the design of both experimental studies and the built environment. The analysis allows highlighting limitations, potential improvements and future opportunities in this field of research, thus providing a reference for further investigations aimed at a deeper understanding, modeling, and prediction of the impacts caused by the main indoor variables on human comfort and performance
Multi-Domain Assessment of the Impact of Biophilic Design Strategies for the Design of Workplaces in Virtual Reality
No full textA recent interest in implementing Nature-Based Solutions through Biophilic Design (BD) strategies has risen for the creation of comfortable indoor environments. Despite lab studies indicating benefits for work efficiency, the lack of preliminary design assessments has hindered their implementation. Virtual Reality (VR) has emerged as an effective tool for data collection in highly realistic environments, addressing such limitations. While current research on BD has mainly emphasized the visual connection with nature, it is important to note that individual experiences are multisensorial. This paper presents an innovative design approach for the preliminary assessment of BD strategies in VR. A case study compares three office layouts (Indoor Green – IG; Outdoor Green – OG; Non-Biophilic - NB) and three acoustic scenarios (Office – O; Office + Traffic – O + T; Office + Nature – O + N) with 198 participants performing cognitive tasks for each acoustic condition, alongside surveys. Results of sense of presence, immersivity (visual), sensory congruency (acoustic), and cybersickness disorders indicate the effectiveness of VR in the preliminary evaluation of BD interventions (ecological validity). The outcomes of the cognitive test highlight a positive influence of audio-visual connections with nature on working memory, inhibition, and task-switching performance. The most supportive visual*acoustic condition is identified as Natural sound in the IG setting, while O + T in the NB environment proves to be the most disruptive. The findings reveal a significant impact of the acoustic environment on the soundscape assessment: the O + N scenario enhances both pleasantness and eventfulness compared to the O scenario. An interaction between audio-visual stimuli was observed regarding pleasantness, with IG being more effective in the O + N scenario, and OG in the O + T scenario
Using listening effort assessment in the acoustical design of rooms for speech
No full textThis study addresses the issue of an enhanced acoustical design of rooms for speech, which besides targeting high speech intelligibility also ensures minimal effort in speech reception. Speech-in-noise tests in the Italian language were proposed to normal-hearing young adults, both in situ, within an existing university classroom, and via headphones, using auralized signals obtained from acoustic simulations of the same environment. Later, auralization was used to investigate the effect of realistic modifications to the room acoustics (acoustical treatment of a wall, change of the room size) by altering the virtual model of the classroom. The speech reception performance was characterized by using both the number of words correctly recognized (speech intelligibility, IS) and two estimates of listening effort: the behavioral measure of response time (RT) and a subjective judgement on a rating scale (LE). Firstly, the correspondence between the IS, RT and LE results in situ and in auralized conditions was considered and discussed. Then, the effectiveness of the three metrics in outlining the effect of the acoustic changes of the room was analyzed. The results showed that there were no differences between the compared acoustic conditions in terms of IS. The effects of the characteristics of the room acoustics were instead discriminated when RT and LE were considered, with the greatest number of significant differences observed by using RT. Using RT therefore seems to be an effective and promising strategy to better discern the effects of the room acoustics and to enhance the acoustical design of rooms for speech
Speech intelligibility and listening effort in university classrooms for native and non-native Italian listeners
No full textListening effort describes the allocation of attentional and cognitive resources for successful listening. In adverse conditions, the mental demands for listening increase, interfering with other cognitive functions. This is especially relevant in learning spaces, where complex tasks that recruit more cognitive resources (e.g. memorization of information and comprehension) are performed by the students. This study focuses on the case of university classrooms and investigates the effects of different types of masking noise on both speech intelligibility and listening effort. Speech-in-noise tests in the Italian language were presented to 25 young adults with normal hearing (13 native and 12 non-native listeners) within an existing university classroom located in Bozen-Bolzano (Italy). The tests were presented in three listening conditions (quiet, stationary noise, and fluctuating noise), grouping the listeners around two locations within the classroom. The task performance was assessed using both speech intelligibility and two proxy measures of listening effort: response time and subjective ratings of effort. Longer response times and higher subjective ratings were taken to reflect increased listening effort. Results in noisy conditions were compared to the quiet condition. A disadvantage in task accuracy performance was found for non-native compared to native listeners; concerning response time, it was found that when the target signal is masked by a fluctuating noise, additional processing time is requested to non-native listeners compared to their native peers. The interaction was not pointed out by subjective ratings, supporting the hypothesis of a different sensitivity to listening conditions of the two proxy measures of listening effort
On The Enhanced Acoustic Design Of The Indoor Environments: Correspondence Of Perceptual Quantities Between Real And Simulated Sound Fields
Full text linkIn the design of indoor spaces where speech communication takes on a central role (e.g., classrooms, conference rooms…), the influence of the sound environment on the occupants’ performance needs to be addressed. In order to guarantee a comfortable communication experience, the acoustic design of such spaces have to ensure, beside a high percentage of correctly heard words (i.e., intelligibility), also a minimal effort in the speech reception process. An effortful listening, as produced for instance by the presence of background noise and/or reverberation, requires the involvement of an increased amount of cognitive resources, and, if sustained over a prolonged period may compromise occupants’ learning and cognitive achievements. The present study specifically addresses the issue of an improved acoustical design of the rooms for speech, based on both intelligibility and listening effort results. For the scope, the correspondence between the results of speech-in-noise tests presented within an existing university classroom and via headphones, using auralized signals obtained from acoustic simulations of the same environment is investigated. In fact, whereas the reliability of acoustical simulations has been widely confirmed as regards the predicted objective acoustic parameters, and the speech intelligibility data, to date an ecological validation of the listening effort metrics is still lacking, and is needed to understand how well results obtained by virtual acoustics predict the everyday realistic communication situations. Simulations of a university classroom with a volume of 198 m3 and acoustical treatment on a lateral wall were carried out with an acoustical CAD software. In order to obtain realistic simulations, the model was calibrated with octave-band field measurements of reverberation and clarity parameters. Binaural impulse responses (BRIRs) were calculated in two listening positions within the classroom, and convolved with anechoic speech and stationary noise, to obtain the auralized stimuli for the speech-in-noise tests. Speech and noise sound pressure levels were calibrated with reference to the values measured during the in situ tests. Consonant confusion tests (Diagnostic Rhyme Tests) in the Italian language were proposed to normal-hearing young adults. The tests were firstly presented in the real classroom, and then in laboratory conditions, via headphones. During the experiments, data on the number of words correctly recognized, auditory response times (RT, behavioral measure of listening effort) and subjective ratings of listening effort (LE) were collected. The statistical analyses showed that both IS and RT data in auralized conditions matched the corresponding results obtained with in situ testing; the RT metric showed a greater sensitivity than IS, being able to discriminate between the listening position within the classroom. As concern LE, the results were found to depend on the mode of presentation, suggesting that beside the auditory stimulus other factors (e.g., attention, experimental setup…) affect the subjective response. Based on the comparison of the results in auralized and in situ conditions, it can be said that the auralization techniques allow to recreate perceptually equivalent environments as regards the IS and RT measures, and that the integration of the two metrics would be of benefit the acoustical design process
Human sounds and associated tonality disrupting perceived soundscapes in protected natural areas
Full text linkIn protected natural areas (PNAs), at popular scenic spots, visitors often contribute to noise pollution through their behaviour. The decibel-focused monitoring doesn’t capture the quality of an acoustic environment, human behaviour and perception. A mixed-methods framework, based on the ISO 12913 series, was tested in four European PNAs to address this gap. During five soundwalks (7–12 km long) organised by the Silenzi in Quota initiative, 443 questionnaires were gathered across 28 evaluation points, alongside corresponding binaural measurements. Acoustic environments as silent as LAeq = 31 dB and as loud as LAeq = 76 dB were observed, eliciting perceptions from very calm to chaotic. Psychophysical measures (loudness, sharpness, roughness, fluctuation strength and tonality) were calculated. The impact of the perceived sound source dominance, visual landscape quality and psychophysical and environmental acoustic features on the perceived soundscape pleasantness and eventfulness was analysed via Linear Mixed-Effects Models (LMMs). Perceived sound source type data- and psychophysical data-based models demonstrated higher predictive power than those based on sound pressure level metrics. Amongst the sounds of nature, water sounds demonstrated the strongest association with higher pleasantness and eventfulness. Unlike in urban context, presence of human sounds, associated with increased tonality, was the major factor driving the perception of chaotic soundscapes, revealing the detrimental effect of human behaviour on the experience of PNAs
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