Acoustic tweets and blogs: Using social media in an undergraduate acoustics course

Each fall, the author teaches an undergraduate architectural acoustics course to around 40 third-year architectural engineering students at the University of Nebraska. Beginning in 2011, a social media component was introduced to explore the use of this technology and how it may supplement the students\u27 learning experience. Students were given an opportunity to receive extra credit by using Twitter and/or blogging about course material using a set hashtag (#AE3300) or through the course website. Results were positive, and the author will discuss pros and cons that she has experienced in adding this social media component. Suggestions for future implementations and examples of student participation will be presented

Acoustic tweets and blogs: Using social media in an undergraduate acoustics course

Each fall, the author teaches an undergraduate architectural acoustics course to around 40 third-year architectural engineering students at the University of Nebraska. Beginning in 2011, a social media component was introduced to explore the use of this technology and how it may supplement the students\u27 learning experience. Students were given an opportunity to receive extra credit by using Twitter and/or blogging about course material using a set hashtag (#AE3300) or through the course website. Results were positive, and the author will discuss pros and cons that she has experienced in adding this social media component. Suggestions for future implementations and examples of student participation will be presented

Development of a Model to Predict the Likelihood of Complaints due to Assorted Tone-in-Noise Combinations

This paper develops a model to predict if listeners would be likely to complain due to annoyance when exposed to a certain noise signal with a prominent tone, such as those commonly produced by heating, ventilation, and air-conditioning systems. Twenty participants completed digit span tasks while exposed in a controlled lab to noise signals with differing levels of tones, ranging from 125 to 1000 Hz, and overall loudness. After completing the digit span tasks under each noise signal, from which task accuracy and speed of completion were captured, subjects were asked to rate level of annoyance and indicate the likelihood of complaining about the noise. Results show that greater tonality in noise has statistically significant effects on task performance by increasing the time it takes for participants to complete the digit span task; no statistically significant effects were found on task accuracy. A logistic regression model was developed to relate the subjective annoyance responses to two noise metrics, the stationary Loudness and Tonal Audibility, selected for the model due to high correlations with annoyance responses. The percentage of complaints model showed better performance and reliability over the percentage of highly annoyed or annoyed

Objective and Subjective Evaluation of the Use of Directional Sound Sources in Auralizations

Omni-directional sources are often used in room acoustic computer simulations, as opposed to directional sources, since measured directivity data are quite limited and difficult to obtain. The purpose of this study is to investigate the objective and subjective significance of adding more complex directivity to the sources used in computer simulations and auralizations. A simple hall was used as the modelled space in the software program ODEON. Three source positions on stage and three receiver audience positions were chosen. Impulse responses (IRs) were calculated for the nine source/receiver combinations, using (a) an omni-directional source, (b) a highly directional source beaming in a sixteenth-tant of a sphere, and (c) three realistic sources: piano, singing voice and violin. The directivity data for the three realistic sources, obtained from the Physikalisch-Technischen Bundesanstalt website, were available in octave bands from 1 kHz – 4 kHz for the piano and violin, and from 125 Hz – 4 kHz for the singing voice. The objective measures evaluated were Sound Pressure Level (SPL), Reverberation Time (T60) and Clarity Index (C80). In general, there is at least 5% difference in T60 data between the omni-directional source and the realistic directional ones. Differences in SPL and C80 are more irregular across frequency bands and appear to be more apparent for sources with higher directivity index. For select source/receiver combinations, the IRs resulting from each source directivity have been convolved with anechoic musical recordings of piano, singing and violin to produce auralizations. Subjective testing revealed a noticeable difference between the omni-directional and the sixteenth-tant sources, but not with the realistic sources

Objective and Subjective Evaluation of the Use of Directional Sound Sources in Auralizations

Omni-directional sources are often used in room acoustic computer simulations, as opposed to directional sources, since measured directivity data are quite limited and difficult to obtain. The purpose of this study is to investigate the objective and subjective significance of adding more complex directivity to the sources used in computer simulations and auralizations. A simple hall was used as the modelled space in the software program ODEON. Three source positions on stage and three receiver audience positions were chosen. Impulse responses (IRs) were calculated for the nine source/receiver combinations, using (a) an omni-directional source, (b) a highly directional source beaming in a sixteenth-tant of a sphere, and (c) three realistic sources: piano, singing voice and violin. The directivity data for the three realistic sources, obtained from the Physikalisch-Technischen Bundesanstalt website, were available in octave bands from 1 kHz – 4 kHz for the piano and violin, and from 125 Hz – 4 kHz for the singing voice. The objective measures evaluated were Sound Pressure Level (SPL), Reverberation Time (T60) and Clarity Index (C80). In general, there is at least 5% difference in T60 data between the omni-directional source and the realistic directional ones. Differences in SPL and C80 are more irregular across frequency bands and appear to be more apparent for sources with higher directivity index. For select source/receiver combinations, the IRs resulting from each source directivity have been convolved with anechoic musical recordings of piano, singing and violin to produce auralizations. Subjective testing revealed a noticeable difference between the omni-directional and the sixteenth-tant sources, but not with the realistic sources

Performance Review of Indoor Noise Criteria

Currently there are a number of indoor noise criteria used to quantify the level of background noise in rooms, including Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC Mark II) and others. This paper reviews the pros and cons of each of these and then compares the values measured in existing classrooms in the Omaha area. The authors are in the process of subjectively comparing these various criteria to determine which method best correlates with human perception. The subjective testing methods and preliminary results are discussed

Analyses of Crowd-Sourced Sound Levels of Restaurants and Bars in New York City

For several decades, there has been a significant need to better educate the public about noise pollution. A small number of small-scale studies have focused on the sound levels of restaurants and their impact on health and hearing. There have also been an increasing number of media articles stating that eating and drinking venues are getting increasingly loud making it more difficult for people to connect with others in conversation. This study reports on an exploratory large-scale noise survey of sound levels of 2,376 restaurants and bars in New York City using a novel smart-phone application and categorized them based on how quiet or loud they were. The results suggest that (1) a significant number of venues have high sound levels that are not conducive to conversation and may be endangering the health of patrons and employees (2) that the reported sound levels by the venue managers on their online public business pages generally underestimated actual sound levels, and (3) the average sound levels in restaurants and bars are correlated by neighborhood and type of cuisine

Higher Sound Levels in K-12 Classrooms Correlate to Lower Math Achievement Scores

Sound levels from occupied classrooms have been gathered from 220 classrooms across four grade levels (3, 5, 8 and 11) over six school days each and processed with k-means clustering into speech and non-speech clusters. Three metrics describing the classroom acoustics, including the average daily A-weighted equivalent level for non-speech, the average daily difference between the A-weighted equivalent levels for speech and nonspeech (a signal to noise ratio), and the mid-frequency averaged reverberation time, were analyzed against classroom-aggregated standardized reading and math achievement test scores, while controlling for classroom demographics including socioeconomic status. Interactions between the metrics and demographics were also tested. A statistically significant relationship was found between the average daily non-speech levels in classrooms and math test scores; higher daily non-speech levels were correlated with lower math test scores (p \u3c 0.05). No statistically significant main effects of acoustic metrics were found on reading achievement. There were some significant differences and an interaction found between grades, but these may be due to uneven sample distributions as there were fewer grade 8 and 11 classrooms measured. Children learn in occupied classrooms, and the findings from this investigation based on data from occupied conditions suggest that designing for lower unoccupied sound levels can lead to occupied environments that are conducive to better student learning outcomes

Effects of Noise, Reverberation and Foreign Accent on Native and Non-Native Listeners’ Performance of English Speech Comprehension

A large number of non-native English speakers may be found in American classrooms, both as listeners and talkers. Little is known about how this population comprehends speech in realistic adverse acoustical conditions. A study was conducted to investigate the effects of background noise level (BNL), reverberation time (RT), and talker foreign accent on native and non-native listeners\u27 speech comprehension, while controlling for English language abilities. A total of 115 adult listeners completed comprehension tasks under 15 acoustic conditions: three BNLs (RC-30, RC-40, and RC-50) and five RTs (from 0.4 to 1.2 s). Fifty-six listeners were tested with speech from native English-speaking talkers and 59 with native Mandarin-Chinese-speaking talkers. Results show that, while higher BNLs were generally more detrimental to listeners with lower English proficiency, all listeners experienced significant comprehension deficits above RC-40 with native English talkers. This limit was lower (i.e., above RC-30), however, with Chinese talkers. For reverberation, non-native listeners as a group performed best with RT up to 0.6 s, while native listeners performed equally well up to 1.2 s. A matched foreign accent benefit has also been identified, where the negative impact of higher reverberation does not exist for non-native listeners who share the talker\u27s native language