Effects of Room Reflectance and Background Noise on Perceived Auditory Distance

Perception ◽  
1989 ◽  
Vol 18 (3) ◽  
pp. 403-416 ◽  
Author(s):  
Donald H Mershon ◽  
William L Ballenger ◽  
Alex D Little ◽  
Patrick L McMurtry ◽  
Judith L Buchanan
Keyword(s):  
Background Noise ◽  
Wide Band ◽  
Physical Distance ◽  
Reverberation Time ◽  
Verbal Reports ◽  
Repeated Presentation ◽  
Auditory Distance ◽  
Stimulus Target ◽  
Masking Stimulus ◽  
High Reflectance

Perceptions of egocentric auditory distance were investigated within an environment for which the reverberation time could be systematically varied without changes in the size or shape of the room. Two levels of wide-band background noise, differing by 20 dB, were used as a masking stimulus. Target sounds were presented from distances between 0.75 and 6.0 m and verbal reports of distance were collected from 288 listeners in two separate experiments. Changes in physical distance produced variation in reported distance in each configuration. Reported distance was generally proportional to real distance, but considerably underestimated when room reflectance was low. When room reflectance was high ( T60 ≈ 1.7 s for the range of frequencies used), initial reports of distance were often overestimates; upon repeated presentation, judgments in the high reflectance room became more nearly veridical. The effect of increasing the background noise level was to decrease the perceived distance. These findings are in accord with expectations based upon the importance of reverberation cue(s) to distance and upon previous analyses from this laboratory.

Relation between Judged and Physical Distance in Multicue Conditions as a Function of Instructions and Tasks

1975 ◽  
Vol 41 (1) ◽  
pp. 171-178 ◽  
Author(s):  
Steven P. Rogers ◽  
Walter C. Gogel
Keyword(s):  
Physical Distance ◽  
Depth Interval ◽  
Verbal Reports ◽  
Bisection Task ◽  
Interval Reproduction

Using a rod adjustable in distance, 48 Os produced equal depth intervals along a floor of a visual alley (interval reproduction) or bisected a given depth interval into two equal parts (bisection). Also, verbal reports were obtained of a depth interval located at a near and farther distance from O (absolute judgments). Two kinds of instructions, “apparent” and “objective,” were used with different Os with each of the three tasks. There was an over-all tendency ( p = .05 on two of three tasks) for apparent instructions to produce less over-constancy or more under-constancy of distance than that produced by objective instructions. This tendency is consistent with a cognitive interpretation of over-constancy of distance. Clear over-constancy was obtained only by the combination of objective instructions and the bisection task. Clear under-constancy was obtained only by the combination of apparent instructions and the method of absolute judgments. The reason for the effect of task on magnitude of distance constancy is not understood.

Sound environment quality in nursing units in Chinese nursing homes: A pilot study

2020 ◽  
Vol 27 (4) ◽  
pp. 283-298
Author(s):  
Hui Xie ◽  
Bingzhi Zhong ◽  
Chang Liu
Keyword(s):  
Nursing Homes ◽  
Nursing Staff ◽  
Noise Level ◽  
Background Noise ◽  
Subjective Evaluation ◽  
Reverberation Time ◽  
Staff Members ◽  
Background Noise Level ◽  
Sound Environment ◽  
Nursing Station

Recent studies have investigated sound environment in nursing homes. However, there has been little research on the sound environment of nursing units. This research sought to address this gap. Subjective evaluations were gathered using questionnaire surveys of 75 elderly residents and 30 nursing staff members in five nursing units of five nursing homes in Chongqing, China. Background noise level and reverberation time were measured in five empty bedrooms, five occupied bedrooms and five occupied nursing station areas, in five nursing units. The subjective evaluation results indicate that the residents stay in the nursing units for most of their waking hours. The residents and nursing staff had strong preferences for natural sounds, with the lowest perceptions of these in the nursing units. The background noise level in all the occupied bedrooms exceeded Chinese standards for waking and sleeping hours. Only 20% of the occupied nursing station areas were below the allowable noise level for recreation and fitness room during sleeping hours. The nursing station area was identified as the main source of noise in the unit during waking hours. The average background noise level of the occupied bedrooms was 3–12 dBA higher than that of the empty bedrooms during sleeping hours. Attention should be given to the implementation of noise specifications for sleeping hours. The reverberation time of the bedrooms was within the range of 0.44–0.68 s, and in the nursing station areas it was 0.63–1.54 s.

Poor Listening Conditions Impair Memory for Intelligible Lectures: Implications for Acoustic Classroom Standards

2009 ◽  
Vol 16 (3) ◽  
pp. 257-265 ◽  
Author(s):  
Robert Ljung ◽  
Patrik Sörqvist ◽  
Anders Kjellberg ◽  
Anne-Marie Green
Keyword(s):  
University Students ◽  
Background Noise ◽  
Speech Intelligibility ◽  
Broadband Noise ◽  
Speech Signals ◽  
Reverberation Time ◽  
Signal To Noise ◽  
Memory And Learning ◽  
What Is Said ◽  
Degraded Speech

This paper reports two experiments on the effects of degraded speech signals on memory for spoken lectures. Experiment 1 showed that broadband noise impairs university students' memory for a spoken lecture, even though the participants heard what was said. Experiment 2 showed that reverberation has detrimental effects to school adolescents' memory for spoken lectures, similar to broadband noise. The results suggest that poor listening conditions (resulting from background noise and/or long reverberation time) impair memory and learning, even if the conditions allow the listeners to hear what is said. Since the goal for students and pupils attending to lectures is to remember the lecture rather than just hearing what is said, the results presented here indicate that standards for acceptable signal-to-noise ratios and reverberation times in buildings designed for learning should consider the distinction between speech intelligibility and memory. Standards should be based on memory criteria instead of intelligibility criteria.

scholarly journals Penilaian Kualitas Akustik Masjid Raudhaturrahman Padang Tiji Menggunakan Simulasi Ecotect

2020 ◽  
Vol 2 (2) ◽  
pp. 357-367
Author(s):  
Yulida Yani
Keyword(s):  
Background Noise ◽  
Simulation Method ◽  
Reverberation Time ◽  
Religious Rituals ◽  
Religious Significance ◽  
Acoustic Quality ◽  
Unique Shape ◽  
High Degree

Mosque is a place of worship for Moslems. It has profound religious significance for the community; it is important that people feel serenity therein. In addition, they need to be able to hear sounds clearly so that they can perform their religious rituals like prayers smoothly and it is also crucial for them to hear speeches with a high degree of intelligibility. This study assessed the acoustic quality of Raudhaturrahman prayer's room, having a unique shape with the dome ceiling covering all dimensions of the building.  This study aims at finding the condition, causes, and improving the acoustic quality to meet the prayer's room acoustic needs.  This study specifically focused on calculating the background noise and reverberation time using the Ecotect Simulation method.  The simulation result demonstrates that the calculation of reverberation time (RT) and the measurement of background noise have not met the desired standard. This study found that the value for RT with occupancy 0%, 50%, 100% is 18, 29s, 7, the 80s, and 4, 71s.  In addition, the result of the background noise is 60 dB.  In conclusion, the acoustic of the Raudhaturrahmah mosque prayer's room is of inferior quality since it does not meet the standard of reverberation time (RT) and background noise for the speech purpose of the room.

Spectral Content as a Cue to Perceived Auditory Distance

Perception ◽  
1992 ◽  
Vol 21 (3) ◽  
pp. 405-416 ◽  
Author(s):  
Alex D Little ◽  
Donald H Mershon ◽  
Patrick H Cox
Keyword(s):  
Sound Source ◽  
High Frequency ◽  
Wide Band ◽  
Sound Level ◽  
Auditory Stimuli ◽  
Spectral Information ◽  
Frequency Content ◽  
Spectral Content ◽  
Auditory Distance ◽  
High Frequency Content

Changes in the spectral content of wide-band auditory stimuli have been repeatedly implicated as a possible cue to the distance of a sound source. Few of the previous studies of this factor, however, have considered whether the cue provided by spectral content serves as an absolute or a relative cue. That is, can differences in spectral content indicate systematic differences in distance even on their first presentation to a listener, or must the listener be able to compare sounds with one another in order to perceive some change in their distances? An attempt to answer this question and simultaneously to evaluate the possibly confounding influence of changes in the sound level and/or the loudness of the stimuli are described in this paper. The results indicate that a decrease in high-frequency content (as might physically be produced by passage through a greater amount of air) can lead to increases in perceived auditory distance, but only when compared with similar sounds having a somewhat different high-frequency content, ie spectral information can serve as a relative cue for auditory distance, independent of changes in overall sound level.

scholarly journals Penilaian kualitas akustik masjid raudhaturrahmah Padang Tiji dengan menggunakan simulasi ecotect

2021 ◽  
Vol 4 (1) ◽  
pp. 18-26
Author(s):  
Yulida Yani
Keyword(s):  
Background Noise ◽  
Reverberation Time

Masjid merupakan tempat ibadah umat islam yang memiliki pengaruh penting bagi masyarakat, dalam melakukan ibadah perlu adanya ketenangan dan kejelasan bicara agar pesan yang disampaikan dapat tersalurkan dengan jelas dan baik. Dalam penelitian ini ruang yang digunakan untuk simulasi ialah ruang shalat masjid Raudhaturrahmah. Tujuan penelitian adalah untuk mengetahui kondisi, penyebabnya dan memperbaiki kualitas akustik dengan penambahan plafond serta material serap, agar sesuai dengan kebutuhan ruang percakapan masjid. Fokus utama penelitian adalah menghitung tingkat bising latar belakang (background noise), dan waktu dengung (reverberation time). Metode yang digunakan adalah simulasi dengan menggunakan software Ecotect yang mampu menganalisis kinerja akustik. Hasil dari simulasi memperlihatkan bahwa kalkulasi waktu dengung (RT) dan pengukuran background noise belum memenuhi kriteria yang telah ditetapkan. nilai yang dihasilkan untuk RT dengan occupancy 0%, 50%, 100% ialah 18,29 s, 7,80 s, dan 4, 71 s. sedangkan hasil dari background Noise ialah 60 dB. Dari penelitian ini menghasilkan solusi untuk memperbaiki waktu dengung dan background noise dengan menambah plafond dan material serap. Setelah penambahan Plafond dan material serap nilai akustik yang dihasilkan lebih optimal dibandingkan dengan kondisi exiting.

scholarly journals Acoustic quality assessment in a classroom through simulations and measurements

2021 ◽  
Vol 9 (72) ◽  
Author(s):  
Eriberto Oliveira do Nascimento ◽  
Paulo Henrique Trombetta Zannin
Keyword(s):  
Background Noise ◽  
Speech Intelligibility ◽  
Reverberation Time ◽  
Vocal Health ◽  
Quality Requirements ◽  
Transmission Index ◽  
Speech Transmission ◽  
Acoustic Quality ◽  
Acoustic Comfort ◽  
Minimum Requirements

The acoustic quality in a classroom directly impacts the educational relationship between the student and the teacher, reducing speech intelligibility. In addition, inadequate acoustic comfort burdens the vocal health of teachers. This study evaluated a classroom at the Federal University of Paraná, Campus Centro Politécnico, to verify its acoustic quality. The measurements of the acoustics descriptors: Reverberation Time (RT), Definition (D50), Central Time (Ts), Early Decay Time (EDT) were performed according to the ISO 3382-2 standard, concerning Noise Curves (NC) and Background Noise (BGN) these were evaluated by the  NBR 10152 and S12.2 standards. The Speech Transmission Index (STI) was measured according to IEC 60268-16 and evaluated according to ISO 9921. The useful-detrimental ratio (U50) and the other descriptors were simulated in the ODEON software version 11. Thus, the results showed that the evaluated room did not meet the minimum requirements in terms of acoustic quality, for the descriptors RT, STI, Ts, D50, RF, and NC. Simultaneously, the RT and STI were also outside the limits established by the German and Finnish standards. Therefore, it is concluded that the evaluated classroom did not reach the minimum acoustic quality requirements.

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