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- Keyword
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- Effects of Noise and Reverberation on Human Perception and Performance (12)
- Room acoustics (12)
- Noise (11)
- Computer Modeling and Prediction of Room Acoustics (7)
- Linking Room Acoustic Subjective Perception and Objective Metrics (7)
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- Classroom acoustics (6)
- Human performance (6)
- Human perception (5)
- Reverberation (5)
- Speech comprehension (5)
- Auralization (4)
- Building mechanical systems (4)
- Scattering and Diffusion in Room Acoustics (4)
- Background noise (3)
- Coupled Volume Room Acoustics (3)
- Noise criteria (3)
- Violin Acoustics (3)
- Non-native (2)
- Reverberation time (2)
- Student achievement (2)
- Tones (2)
- Violin acoustics (2)
- Acoustic radiation (1)
- Acoustic reflectors (1)
- Annoyance (1)
- Auralizations (1)
- Background Noise (1)
- Building mechanical noise (1)
- Classroom Acoustics (1)
- Coupled volume (1)
Articles 31 - 43 of 43
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Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs
Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs
Lily M Wang
Nearfield acoustic holography (NAH) is applied to visualize the acoustic radiation from bowed violins across a frequency range from 294 Hz to 3 kHz. These visualizations are employed to localize regions of acoustic radiation from surfaces of violins. Three violins were tested: a common student instrument by Scherl and Roth; Hutchins violin SUS295, which has been the subject of many previous investigations; and a Hutchins mezzo violin from the Violin Octet set of instruments, which is longer, broader and thinner than a standard instrument. The violins were bowed continuously with an open-frame mechanical bowing machine, while NAH measurements were made …
Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang
Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang
Lily M Wang
This study investigated the effects of noise from building mechanical systems with tonal components on human task performance and perception. Six different noise conditions based on in-situ measurements were reproduced in an office-like setting; all were set to approximately the same sound level (47 dBA) but could have one particular tonal frequency (120 Hz, 235 Hz, or 595 Hz) at one of two tonal prominence ratios (5 or 9). Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately 1 hour to each noise condition. Results show that the noise …
Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak
Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak
Lily M Wang
The goal of this study was to investigate the effects of noise from building mechanical systems with time-varying fluctuations on human task performance and perception, and to determine how well current indoor noise rating methods account for this performance and perception. Six different noise conditions with varying degrees of time-varying fluctuations, many focused in the low frequency rumble region, were reproduced in an office-like setting. Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately one hour to each noise condition. Results show that the noise conditions with higher sound …
Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik
Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik
Lily M Wang
This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14 males) were exposed to all combinations of five thermal conditions (PMV +1 [79.6°F:26.4°C], PMV +0.5 [75.8°F:24.3°C], PMV 0 [72.1°F:22.3°C], PMV -0.5 [68.3°F:20.2°C], and PMV -1 [64.6°F:18.1°C]), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimicked noise from building ventilation systems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant …
A Review Of Diffuse Reflections In Architectural Acoustics, Jonathan Rathsam, Lily M. Wang
A Review Of Diffuse Reflections In Architectural Acoustics, Jonathan Rathsam, Lily M. Wang
Lily M Wang
Diffuse reflections have received increasing attention in architectural acoustics over the past quarter century. The term diffuse refers to non-specular directions. This paper identifies three mechanisms that cause diffuse reflections. Practitioners have found that changing specular reflections into diffuse reflections can reduce noise and echoes both indoors and outdoors. Developers of acoustical modeling software have also found that modeling diffuse in additional to specular reflections produces more accurate predictions. The final portion of this paper presents results for a study of scattering coefficients in acoustical modeling software.
Appropriate Characterization Of Background Noise Levels In The Workplace, Erica E. Bowden, Lily M. Wang
Appropriate Characterization Of Background Noise Levels In The Workplace, Erica E. Bowden, Lily M. Wang
Lily M Wang
Overall loudness is not the only quality of indoor background noise that affects occupants. The distribution of noise across frequency (pitch), whether or not the noise contains tones, and whether or not the noise changes over time must also be considered. There are several indoor noise criteria systems available to quantify the background noise in rooms, but many of them do not account for these factors. These systems are commonly used by architects and engineers, and often incorporated into manufacturer’s data, design guides, and standards. There is much debate over which of the criteria systems best reflect how occupants will …
Apparatus For Studying Wave Motion And Sound At The University Of Nebraska– Lincoln's “Historical Scientific Instrument Gallery”, Lily M. Wang, M. Eugene Rudd
Apparatus For Studying Wave Motion And Sound At The University Of Nebraska– Lincoln's “Historical Scientific Instrument Gallery”, Lily M. Wang, M. Eugene Rudd
Lily M Wang
The University of Nebraska–Lincoln's “Historical Scientific Instrument Gallery,'' compiled by the second author in 1998, contains approximately 700 inventoried items and may be visited on-line at http://physics.unl.edu/outreach/histinstr/. Amidst the collection are several acoustical instruments that were used in the early 1900s. These include equipment that demonstrate wave motion (traveling wave machine, mercury ripple dish, vibration microscope), wave interference (interference machine), resonance conditions (Helmholtz resonators, vibrating rods, singing flames, sonometer), and sound generation (Galton's whistles, high-frequency tuning forks, large tuning forks, organ pipes, siren saw). A review of the equipment and the history of their use at the University of Nebraska …
Lv-11-C031: Measured Levels Of Hospital Noise Before, During, And After Renovation Of A Hospital Wing, And A Survey Of Resulting Patient Perception, Cassandra H. Wiese, Lily M. Wang
Lv-11-C031: Measured Levels Of Hospital Noise Before, During, And After Renovation Of A Hospital Wing, And A Survey Of Resulting Patient Perception, Cassandra H. Wiese, Lily M. Wang
Lily M Wang
Acoustic conditions in hospitals can negatively influence a patient’s physical and psychological health. This paperreports on noise levels measured before, during, and after renovation of a hospital wing in an Omaha, Nebraska, facility thatregularly receives unsatisfactory noise scores on patient satisfaction surveys. Sound pressure levels were logged every 10seconds over four-day periods in three different locations: at the nurses' station, in the hallway, and in a nearby patient’sroom. The resulting data have been analyzed in terms of A-weighted equivalent sound levels (LAeq) as well as variousexceedance levels (Ln). Results indicate that sound levels did not change much due to the …
Measuring Sound Power In Ducted Heating, Ventilating, And Air-Conditioning (Hvac) Systems For Use In Verifying Acoustical Prediction Methods, Steven R. Ryherd, Lily M. Wang
Measuring Sound Power In Ducted Heating, Ventilating, And Air-Conditioning (Hvac) Systems For Use In Verifying Acoustical Prediction Methods, Steven R. Ryherd, Lily M. Wang
Lily M Wang
This paper discusses issues regarding in-situ methods of obtaining sound power at a point in a heating, ventilating and air-conditioning (HVAC) duct system. Such a method is being used as part of a larger investigation on acoustical prediction methods to allow for comparison of measured data to results from attenuation predictions of individual duct elements, such as elbows or dampers. Sound propagation in HVAC duct work is complex. Any measurements of sound energy in the duct must address the characteristics of sound propagation in ducts, end reflections, and air turbulence. Investigations are being conducted to understand the extents to which …
Room Acoustics Computer Modeling: Study Of The Effect Of Source Directivity On Auralizations, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel
Room Acoustics Computer Modeling: Study Of The Effect Of Source Directivity On Auralizations, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel
Lily M Wang
Auralizations are very useful in the design of performing arts spaces, where auralization is the process of rendering audible the sound field in a space, in such a way as to simulate the binaural listening experience at a given position in the modeled space. One of the fundamental modeling inputs to create auralizations is the source directivity. Standard methods involve inputting the measured source directivity, calculating the impulse response and convolving it with a single channel anechoic recording. An initial study was conducted using this method and the results showed significant differences in reverberation time and clarity index when using …
Objective And Subjective Evaluation Of The Use Of Directional Sound Sources In Auralizations, Lily M. Wang, Michelle C Vigeant
Objective And Subjective Evaluation Of The Use Of Directional Sound Sources In Auralizations, Lily M. Wang, Michelle C Vigeant
Lily M Wang
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 …
Implications Of Human Performance And Perception Under Tonal Noise Conditions On Indoor Noise Criteria, Lily M. Wang, Erica E. Ryherd
Implications Of Human Performance And Perception Under Tonal Noise Conditions On Indoor Noise Criteria, Lily M. Wang, Erica E. Ryherd
Lily M Wang
This research investigated differences in task performance and perception under six non-time-varying ventilation-type background noise spectra with differing tonality. The results were related to five indoor noise criteria systems: Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC-Mark II), and the A-weighted equivalent sound pressure level (LAeq). These criteria systems are commonly used in the U.S. building industry, but concerns exist over whether they are appropriate for all noise situations. Thirty test subjects completed three types of performance tasks (typing, reasoning, and math) and answered questions about their perception of the indoor environment under …
Relationships Between Unoccupied Classroom Acoustical Conditions And Elementary Student Achievement Measured In Eastern Nebraska, Lauren M Ronsse, Lily M. Wang
Relationships Between Unoccupied Classroom Acoustical Conditions And Elementary Student Achievement Measured In Eastern Nebraska, Lauren M Ronsse, Lily M. Wang
Lily M Wang
Building standards recommend maximum background noise levels (BNL) and reverberation times (RT) for unoccupied classrooms. However, existing research does not show a consistent correlation between these parameters and student achievement. Through in situ testing, this research seeks to determine what acoustical conditions should be attained in elementary schools for students to meet educational goals. Acoustical measurements were conducted in a Nebraska public school system and correlated to achievement scores from students in the surveyed classrooms. Unoccupied BNLs and RTs were gathered in 34 third and 33 fifth-grade classrooms. Additionally, binaural room impulse response measurements were gathered in a subset of …