bluuebunny/crossref_metadata_2025 huggingface dataset:
Zinc for organ pipe building.
Authors: Angster Judit , Dubovski Zlatko , Miklos Andras
Published: July 2011

Zinc is being used only rarely for organ pipes, since high quality material has not been available. The slightly harder metal makes manual processing of the pipes more complicated for the voicer. Nevertheless zinc is much more cost-efficient. Grillo Werke (Germany) has developed a “soft zinc strip” which is significantly better, as far as workability is concerned, than materials available in the past. This material has been tested to determine to what extent zinc modifies pipe wall vibrations, and how essential the impact of the material would be on the sound. Various pairs of pipes made of plain metal and of zinc have been voiced for the same sound, if possible, according to subjective assessment. The experiments prove that the wall vibration spectra of flue pipes made of various materials clearly show differences. Total velocity spectra recorded by means of 3D scanning Doppler laser vibrometry vary considerably. The results of analyzing the stationary sound spectra and the attack transient, however, allow the voicing of these pipes to the same sound. Recording by a microphone array system also proved that the wall vibration does not have any direct influence on the sound radiation of the pipe.
Material properties of pipes and reeds from the Southeast Asian khaen.
Authors: Hershey Kyle W. , Cottingham James P.
Published: July 2011

The khaen is constructed with free reeds mounted in bamboo pipes and enclosed in a carved hardwood wind chamber. These instruments have traditionally been constructed with simple tools using natural materials, primarily bamboo and wood. Unlike some Asian traditional instruments, the khaen has not undergone modernization, and high quality instruments are still made in the traditional manner by village craftsmen. In the past bamboo could have been used for the reeds as well as the pipes, but metal reeds have been used extensively for some time. Measurements have been made on reeds and pipes from two khaen: one a high quality instrument made in northeastern Thailand and one an inexpensive khaen purchased at an import shop. Analysis and comparison have been made of the physical properties of the bamboo pipes, the composition of the alloys used for the metal reeds, and the mechanical properties of the reed such as the elastic modulus. Comparisons can be made with an earlier published analysis of the properties of the bamboo pipes and metal reeds from a traditionally made khaen [Picken et al., Musica Asiatica 4, 117–154 (1984)].
Collecting data on wind turbine sound to identify causes of identified concerns.
Authors: Palmer William K.
Published: July 2011

Regulations for wind turbines are generally based on A-weighted sound levels, and typical sound spectrums found in the community often from localized sources, such as an exhaust stack. The regulatory limits are generally at levels known to cause little annoyance in the community. Large industrial wind turbines with a sound emitter from 50 to 150 m overhead, and based on a source perhaps 100 m in diameter pose a relatively new source of sound to communities, particularly the rural communities where they are located. Community experience shows that the same A-weighted sound limits that are acceptable for many typical sound spectrums and localized sources and pose a considerable level of annoyance for wind turbines. This paper sets out to identify the differences in the sound levels found at locations 500–600 m from wind turbines (about one-third mile) considered acceptable by regulators near wind turbines, in both spectrum, intensity, duration, and special characteristics, such as tonality or amplitude modulation (cyclical pattern) compared to the sound levels at control sites distant by at least 5000 m (about 3 miles) from wind turbines. An explanation of the data collection method is given, as well as an analysis of extensive sound samples gathered.
Case studies of adaptive acoustical reuse of three historic buildings.
Authors: Siebein Gary W. , Paek Hyun
Published: July 2011

Case studies of the acoustical reuse of three historic buildings all included on the National Register of Historic Places will be presented. Case study 1 is a university library space that was reused as a small performance hall and meeting room. Acoustical interventions in the renovation were extremely limited. Innovative diffusing panels were custom designed and fabricated to fit within existing wood panel dimensions on the walls of the performance area. Sound absorbing materials that had to match the color and dimensions of existing materials were also strategically added to the space. Case study 2 is the conversion of a medium sized church to a performance hall. Impulse response measurements showed sound focusing difficulties in the existing building that had to be reduced through the strategic insertion of sound diffusing systems. Case study 3 was the conversion of old university buildings into state of the art classrooms and faculty offices. The integration of modern air-conditioning systems as well as airborne and impact sound control systems within the historic fabric of the building, was a major design issue.
Examining influences of deafness on behavioral and cortical responses to vibrotactile speech stimuli.
Authors: Auer Edward T.
Published: July 2011

Deaf individuals can rely on somatosensation for the perception of acoustic stimuli. Research into both natural and artificial approaches to support this sensory substitution has led to the observation of enhanced vibrotactile processing in some deaf individuals. Two fundamental questions arise related to this observation. First, what in the experience of deafness could have led to the enhancement of somatosensory processing? Second, what, if any, cortical changes are associated with the processing of somatosensory stimuli in deaf individuals? With regard to the first question, evidence will be presented that suggests that the enhancement may arise as a result of the significant amounts of vibrotactile stimulation some deaf individuals receive from wearing high-powered hearing aids. With regard to the second question, evidence will be presented that suggests that life-long experience with high-powered hearing aids is also associated with the observation of auditory cortex activation by somatosensory stimuli in deaf individuals. Taken together these results support experience driven changes in somatosensory processing of acoustic speech stimuli and associate auditory cortex activation with these changes. These results will be discussed within the context of implications for multisensory processing following cochlear implantation.
Feeling sounds: Auditory influences on touch perception.
Authors: Ro Tony
Published: July 2011

Events occurring in one sensory modality can often affect how we experience sensations in a different sensory modality. For instance, the sound of a mosquito flying near us seemingly enhances sensitivity to touch on our skin. In this talk, I will describe a series of experiments that examines the effects of audition on touch perception, as well as some of the neural substrates underlying them. In addition to describing psychophysical experiments that have revealed systematic ways in which audition influences touch perception, I will discuss a set of experiments using diffusion tensor imaging and functional magnetic resonance imaging that were conducted in neurologically normal subjects as well as on a patient who has a unique form of acquired auditory-tactile synesthesia. Together, these studies illustrate some of the dynamic interactions between our different sensory systems, the neural mechanisms underlying these interactions, and also highlight the plastic properties of sensory processing in the human brain.
Acoustic variability of speakers with dysarthria on word repetition tasks.
Authors: Kim Yunjung
Published: July 2011

Although large variability in acoustic characteristics “across” speakers with dysarthria has been reported in previous studies in the process of describing characteristics of dysarthrias and identifying speech severity, relatively less attention has been paid to acoustic variability “within” speakers with dysarthria [Kim et al., JSLHR (in press)]. This is a theoretically and clinically important question regarding validity and reliability of acoustic parameters as markers of speech disorders or severity, especially given the difficulty in data collection due to the physical condition of speakers and the relatively small number of subjects and trials (repetitions of given items) in previous literature. As a follow-up analysis of Kim et al. (in press), this study aims to examine the degree to which speakers with dysarthria exhibit consistency in repeated articulatory behaviors by measuring variability of selected acoustic measures on word repetition tasks. Acoustic measures include F2 slope for vocalic nuclei and moment analysis for fricatives /s/ and /∫/ produced by 108 speakers with dysarthria and ten healthy controls. These results will be interpreted in terms of dysarthria in general and the different types of dysarthria that are said to be associated with different types of neurological disease.
Prosodic characteristics of speakers with schizophrenia disorders: Preliminary data.
Authors: Beslin Ali E. , Kim Yunjung , Cohen Alex S.
Published: July 2011

This study aims to provide preliminary data on prosodic characteristics of speakers with schizophrenia as the first phase of a larger study that explores acoustic vocal markers of schizophrenia for the ultimate purpose of differential diagnosis of this disorder. Only a few studies have reported acoustic characteristics of individuals with schizophrenia including flattened intonation [Covington et al. (2005)] and an increase in pause duration [Rapcan et al. (2010)] compared to healthy speakers. For this presentation, 100-s-long spontaneous speech samples produced by three female speakers with schizophrenia were analyzed and results were compared to three female speakers with bipolar disorder as a psychiatric control group. Speech recordings were first segmented into a total of 165 breath groups, and then from each breath group, acoustic measures were made including (1) mean and range of fundamental frequency contour, (2) mean and range of intensity contour, (3) duration and frequency of pauses, and (4) speaking/articulation rate. It is expected that the results from these preliminary data will further motivate investigations of negative symptoms of speakers with schizophrenia and the development of automated tools for differential diagnosis of schizophrenia from other psychological conditions known to exhibit symptoms similar to those in schizophrenia such as depression and anxiety.
An investigation of speech production and intelligibility of a post-lingually deaf sequential bilingual adult cochlear implant user, pre- and post-implantation for English and Twi.
Authors: Scibilia Stephanie J.
Published: July 2011

This study investigates changes in speech production for a sequential bilingual adult male who is postlingually deaf (9 years of hearing) following cochlear implantation (CI). Recordings of words in carrier phrases took place at pre-implantation in English (L2) and at the 6-month, 1-year, 1-year-6-month, and 2-year post-implantation marks in L2 and Twi (L1). Normative data were recorded from a typically hearing adult male with a similar linguistic history. Acoustic measurements for L2 include f0, F1, and F2 of vowels, VOT, and spectral measures of s-S. Voice quality measurements for sustained /a/ were also obtained. Acoustic measurements for L1 include F1 of vowels that undergo vowel harmony and f0 of tonal contrasts. Questionnaires about CI usage and self-reported changes in production/perception supplement the acoustic data. Lastly, forced-choice speech intelligibility ratings in L1 and L2 were obtained utilizing inexperienced monolingual listeners of each language separately. Current results suggest preservation of L1 following 16 years of auditory deprivation, phonetic influence of L1 on L2, and fluctuating suprasegmental parameters. These acoustic data will be compared to intelligibility ratings and information from the self-report questionnaires.
Modeling overall voice quality with a small set of acoustic parameters.
Authors: Kreiman Jody , Gerratt Bruce R.
Published: July 2011

Despite the great need for valid measures of voice quality, we are still unable to adequately quantify what a person sounds like. Drawing on recent theoretical and experimental work, we propose assessment of overall quality as a whole, rather than using individual rating scales. This paper describes experiments evaluating a psychoacoustic model that includes vocal tract formant frequencies and bandwidths, four source spectral slope parameters (H1–H2, the slope of the harmonic spectrum from 2–4 kHz and from 450–452 kHz, and the overall spectral slope from H2 to the highest harmonic), the noise-to-harmonics ratio, F0, and slow variability in F0 and amplitude (tremor). To assess the adequacy of this model, we will copy-synthesize 30 pathological voices while manipulating only these parameters. To the extent that listeners judge that the natural and synthetic tokens match exactly, the psychoacoustic model will be considered valid. Discussion will include analysis of mismatches to determine what parameters should be added to or subtracted from the model and its application for use in evaluation of disordered voice quality and modes of phonation. [Work supported by NIH.]
Biomechanical modeling of non-stationary vibrations of the pharyngo-esophageal segment.
Authors: Huettner Bjoern , Herkenhoff Sven , Eysholdt Ulrich , Lohscheller Joerg , Doellinger Michael
Published: July 2011

After total laryngectomy, a substitute voice is generated by means of the tissue vibrations of the pharyngo-esophageal (PE) segment. The quality of the substitute voice significantly depends on the vibration characteristics of the PE segment. A numerical model is presented that allows for the simulation of non-stationary vibrations of the PE segment, i.e. the fundamental frequency varies with time. The introduced time dependent multi-mass model for the PE segment (PE-MMM(t)) has been developed from the non-stationary two-mass model of the vocal folds. The pseudo-glottal opening and vibrations are modeled by 6×2 coupled mass-spring-oscillators placed in two horizontal planes. The masses are arranged to describe enclosed shapes. The model parameters masses, their rest positions, the sub-glottal pressure and the anchor spring couplings are all variable with time. The PE vibrations are described by the time dependent quantities frequency, opening area and pseudo-glottal shape. We will present the PE-MMM(t) that is appropriate to generate self-sustained, non-stationary vibrations. Furthermore, we show dynamics of different model configurations, particular circular and elliptical arranged masses, to simulate different shapes of the PE segment.
Lessons learned from time reversal experiments: Applications to target detection.
Authors: Song Hee-Chun , Kuperman William A. , Hodgkiss William S. , Akal Tuncay , Stevenson Mark
Published: July 2011

Over a decade beginning in 1996 we carried out a series of time reversal experiments jointly with the NATO Undersea Research Centre in coastal water at various frequencies (450 Hz, 850 Hz, 3.5 kHz, and 15 kHz). These experiments and follow-up analysis suggested potential applications to active sonar. Time reversal focuses acoustic energy on a target enhancing the target echo while minimizing the reverberation from the boundaries below and above the focus, thereby resulting in echo-to-reverberation enhancement. These ideas have been confirmed under limited circumstances in our shallow-water acoustic experiments. This talk will discuss acoustic and signal processing lessons learned from these experiments including an acoustic barrier concept and both active and passive reverberation nulling.
Time-reversal in seismology.
Authors: Larmat Carene , Johnson Paul , Guyer Robert
Published: July 2011

This talk is a review of the use and history of time-reversal in seismology. time-reversal has been developed independently in the field of acoustics and in geophysics exploration, without the two communities being aware of the fact, as testifies the lack of the cross-references in early papers. The elegance of time-reversal is that it thrives with complexity. Seismologists have to deal with complex signal transmitted through the earth. Moreover, earthquakes are complex sources, involving different episodes of slip along the fault. Early in the development of time-reversal in seismology, emphasis has been put on the need of accurate numerical schemes to back-propagate the wavefield and the need of relatively dense data. In addition to presenting several of the landmark applications of time-reversal in seismology, several of our results will be outlined. In the last decade, our group has studied the potential of TR with the unique approach of combining laboratory experiments with application to seismology problems. Several applications will be presented: location and characterization of the rupture of the 2004 Parkfield earthquake, location, and retrieval of the sliding motion of glaciers in Greenland, finally imaging of the source location of a seismic signal of particularly emergent nature, the tremor.
The measurement and evaluation of bespoke 3-D absorptive panels: A comparative analysis.
Authors: Zeman John , Dance Stephen , Zepidou Georgia
Published: July 2011

A recent movement of Scandinavian design houses has brought about a new artistic sensitivity to porous sound absorbers in the world of architectural acoustics. These absorbers have vibrant colors and textures never before seen on a mass scale. However, as the design of these absorbers becomes more intricate, the problem arises on how to test such bespoke products in accordance with international standards. A particular problem is the arbitrary size of the products. Monetary and labor constraints keep these absorbers from being produced to a size that will satisfy international requirements. Therefore, a testing methodology and correction factor is needed in order to predict the acoustic performance of the designer products. Although this test methodology is not meant to replace current standards for total surface area criteria, this approach would work as a corollary, allowing materials that could not be easily reproduced to be measured in conjunction with standards despite their size, saving designers and manufacturers both time and money.
Acoustical behavior of colonial churches in Cusco, Peru.
Authors: Jimenez-Dianderas Carlos R.
Published: July 2011

The paper searches for characterizing the acoustical behavior of more than ten colonial churches in Cusco, a southern city of Peru. Cusco was an important city through the Spaniard Colonial Era in Peru; several religious orders established in the area and fix the European styles and building process to the geography, geology and building materials. Through five typical acoustical objective parameters the acoustical environment in each church is defined. A comparison between several positions in each church analyzed and among churches will be presented.
Marine mammal vocalizations: Spectrum analysis.
Authors: Austin Melanie E.
Published: July 2011

Marine mammals communicate underwater using sounds at different frequencies. Some whales speak using low frequency moans, and others communicate using high frequency whistles and clicks. Some sing notes that sweep over different frequencies. Come hear some of the amazing sounds that whales, seals, and walrus make! Look at spectrum plots to see which frequencies make up the sounds. See if you can match pictures of spectrogram plots with the sounds you hear. Also explore the sounds made by common man-made noise sources in the ocean such as ships, sonars, and geophysical survey equipment. In this demonstration, you will learn how to distinguish low frequency and high frequency sounds, both by ear and by eye, through a computer based matching game. You will click on an image of a marine mammal, or a man-made noise source, to hear an audio clip of the sound that each makes. After hearing the sound, try to guess which of the presented spectrum plots matches the sound you heard.
The effects of underwater noise on marine mammals.
Authors: Erbe Christine
Published: July 2011

The marine soundscape is made up of natural ambient sounds, biological sounds, and anthropogenic sounds. Natural ambient sound sources include wind, waves, rain, and ice. Biological sounds include calls emitted by marine mammals, fish, and crustaceans. Water conducts light very poorly but sound very well, which is why marine animals rely heavily on acoustics for communication and navigation. Did you know that fish talk underwater? Anthropogenic, i.e., man-made, sources of sound include ships, harbor construction, petroleum exploration, naval sonar, fish finders, etc. Acoustic ecology encompasses the relationships—mediated through sound—between organisms and their environment. An overview of marine acoustic ecology will be presented with focus on the effects of man-made noise on marine mammals. You will be able to immerse yourself in the underwater soundscape and listen to both man-made and animal sounds. The interference of noise with animal signals will be explored through masked hearing experiments. Come and test if you can hear whale calls in ship noise better than a trained beluga whale from Vancouver Aquarium.
Helmholtz resonator: An empty bottle.
Authors: Ballard Megan S.
Published: July 2011

Helmholtz resonance is the phenomenon of air resonance in a cavity, such as when one blows across the top of an empty bottle. In this demonstration, the sound radiating from the bottle will be described in terms of a lumped acoustic system. Such an explanation applies the long wavelength limit, which allows acoustic devices to be modeled as a harmonic oscillator with two degrees of freedom. For the case of an empty bottle, the air inside the neck of the bottle behaves as the mass element. The air contained in the remainder of the bottle makes up an elastic cushion, which acts as the spring element. Together they form an oscillating system with a specific resonance frequency that can be easily excited, as is well known, by blowing across the opening of the bottle. The relative effects of the mass and stiffness of the system on the pitch of the sound radiated from the bottle will be demonstrated by changing the volume of air in the neck and cavity of the bottle.
Hands-on demonstrations for Project Listen Up: Education outreach part II.
Authors: Carberry Colleen E. , Carpenter Anna E. , Korman Murray S.
Published: July 2011

Midshipmen will be getting involved in an ASA education outreach effort by presenting or video taping a number of acoustical demonstrations geared to promote a hands-on learning experience for middle- and high-school age girl Scouts. This is an extension of the demonstration effort and outreach presented at the ASA Meeting held in Baltimore in 2009. The demos are designed to visualize certain wave effects that will be explained by the Midshipmen “live” or by video. The participants will be free to explore and then control the apparatus and make their own scientific discoveries. The hands-on demonstrations will include (1) a ripple tank with an electronic wave height transducer for wave visualizations or making simple oscilloscope measurements, (2) a torsion wave machine for demonstrating reflection and interference effects, and (3) a forced damped harmonic oscillator apparatus that consists of a subwoofer driver connected to the bottom of a vertical spring that is attached at the top to a hanging mass on a string that is suspended over a pulley. Resonance effects can be easily observed watching the pulley oscillate around 1 Hz. The driver frequency is controlled by adjusting a single knob and looking at the digital display.
Standing waves on piano wire.
Authors: Ferguson Sarah Hargus
Published: July 2011

This demonstration will use a piano wire stretched between two pieces of aluminum exactly 100 cm apart. Plucking this wire will set it into vibration, generating sound waves that we can hear. Touching the wire at different locations along its length will change the way the wire vibrates and, therefore, change the sound we hear.
Pitch perception.
Authors: Werner Lynne , Garinis Angela , Lau Bonnie , Yeager Louise
Published: July 2011

Pitch is the characteristic of sound that varies from low to high. For example, the pitch of a man’s voice is low, while the pitch of a child’s voice is high. Sounds produced by different sources, such as a musical instrument or a person speaking, sound different, but still share the same pitch. These demonstrations will show how different sound waves can have the same pitch.
Experimental study of nonlinear phenomena in an upright piano.
Authors: Chaigne Antoine , Chabassier Juliette
Published: July 2011

Measurements are conducted on an upright piano in order to investigate the nonlinear dynamics of the instrument from the blow of the hammer to the radiated sound in the nearfield. The experimental setup consists in synchronous recording of eight channels: hammer force, string displacement at various points, velocity and force at bridges, soundboard acceleration, and sound pressure. From these measurements, the transmission of vibrations through the instrument is followed in both the time and frequency domains. Excitation of strings at different amplitudes shows the influence of the geometrical nonlinear phenomena in the radiated sound. In the time domain, the most visible consequence of nonlinearity is the presence of a precursor in the force and acceleration waveforms at the bridge. To clearly discriminate between dispersion precursor, due to stiffness, and nonlinear precursor, experiments are conducted on two strings corresponding to limiting cases: the C2 string, where stiffness is dominant, and the E3 string where the geometrical nonlinear effects are preponderant. Fine spectral analysis shows that the transmission of energy from strings to soundboard at the bridge is crucial in enhancing the level of phantom partials in the emitted sound due to quadratic and cubic nonlinearities in the string force.
Vibroacoustics of a gothic harp.
Authors: Waltham Chris , Daltrop Shira , Kotlicki Andrzej , Wolfe Nathan , Elie Benjamin , Gautier François
Published: July 2011

The gothic style of harp was popular across most of Europe from the late medieval period to the Renaissance. To study the vibroacoustic behavior of gothic harps, one was constructed from plans created by the Boston Museum of Fine Arts from a late German model in their collection. The vibrational behaviors of the soundboard and soundbox were measured at various stages of construction of the instrument. Once complete, the instrument was subjected to modal analysis and radiativity measurements using Weinreich’s method. The sound radiation of this harp is dominated by two breathing modes at 188 and 273 Hz and higher modes around 350 Hz, which together function like the A0/T1 resonance pairs seen in the soundboxes of many other instruments including modern concert harps. As the frequency increases, radiation is emitted from higher up the soundboard and from higher soundholes, as has been observed in other harps. Unlike modern instruments, the gothic harp’s thin back plays a large role in sound production.
Dealing with sound generated by a multi-use stadium when background sound exceeds the limits: Political issues and field results.
Authors: Pettyjohn Steven D.
Published: July 2011

Raley Field is home to the River Cats baseball team, a Triple -A minor league affiliate of the Oakland Athletics. This stadium hosts a variety of events besides the baseball games, including concerts. The sound generated by all of these events is governed by the City of West Sacramentos Noise Control Ordinance and the non-transportation performance standards in the General Plan. However, these regulations make no provision with how to deal with situations where background sound levels exceed the sound limits. Nor do the standards deal appropriately with the difference in the frequencies generated by background sound levels compared with those generated by either baseball games or concerts. An agreement was reached to set a limit based on background sound levels that required the events in Raley Field to generate less sound than the background to limit the increase in the total or ambient sound level. The standards are based on hourly Leq and Lmax sound level. Examples of community and concert sound measurements made during concerts and baseball games are presented and compared with standards. The proposed development around the stadium will be explained and compared with potential noise impacts at elevated sites.
Potential noise impacts associated with concert sound from a proposed football stadium.
Authors: Carman Richard , Reyes Carlos , Bensing Silas
Published: July 2011

A proposed new stadium for a national league football team was the subject of a recent Environmental Impact Report prepared for a major redevelopment of a former industrial site in San Francisco, CA. The development will include commercial and residential components, which would be adjacent to existing residential and industrial land. Consequently, potential noise impacts were evaluated for existing and future residential receptors. San Francisco recently revised its noise ordinance adopting relatively low limits for community noise, thus posing interesting challenges for new noise sources. The concept for the new outdoor stadium included a fixed sound system for football games that could result in noise impacts as well as those from crowd noise. This paper, however, will focus on the potential for community noise impacts from outdoor concerts that could be held in the stadium using the performer’s sound system as is typical in this situation. A three-dimensional acoustical model, which included the local topography, stadium geometry, and representative loudspeaker characteristics, was developed to project sound levels in the residential community. The implications of exceeding the noise ordinance limits during a concert and possible mitigation measures are discussed as are the main details and results of the model.
Developing an amplified sound policy for San Francisco’s Golden Gate Park.
Authors: Rosen Alan T.
Published: July 2011

Golden Gate Park in San Francisco hosts many community events, some with amplified sound. Sharon Meadows, near the east end of the Park, hosts events with amplified sound and is in relative close proximity to residential areas. Over the years, neighbors have expressed concern about the level of amplified sound from events at Sharon Meadows. In order to address neighbors’ concerns, a program was initiated by the San Francisco Recreation and Parks Department to develop policies and procedures for monitoring and controlling amplified sound to reasonable levels. The program involved a review of existing city policies for amplified sound, a meeting with affected neighbors to discuss concerns, acoustical measurements during events, and sound propagation testing. The final result was an amplified sound policy that provides limits for sound levels within the park that are based on ambient noise levels in the community. The paper will discuss the development of the policy and the challenges of monitoring and regulating amplified sound in a dynamic urban environment.
Chastain Park’s 63-Hertz compliance criteria: 5 years on.
Authors: Berens Robert
Published: July 2011

Over the years, Atlanta’s open-air Chastain Park Amphitheater has been the source of enormous friction between the city, the venue’s owner, and the wealthy, politically connected residential community abutting the park. In 2005, a study was undertaken to identify the characteristics of concert-event sound to which neighbors were particularly sensitive: Sound levels were monitored throughout the neighborhood during 17 concerts, ranging from quiet jazz and classical performances to rock-and-roll and hip-hop; at a number of locations, measurements were made simultaneously inside and outside homes. The study team confirmed that low-frequency sound was the one feature of concert-related sound that community residents identified as most problematic. A new compliance metric was established to address low-frequency annoyance issues: a two-tiered exceedence threshold, based on 1-min LEQ levels in the 63 Hz octave band measured at the rear of the amphitheater, with a concert-event “exceedence” defined to be either a single 1 min LEQ (63 Hz) level greater than 95 dB or more than ten 1-min LEQ (63 Hz) levels greater than 90 dB. 5 years of data from Chastain’s computer-based concert monitoring system are analyzed to show how effective the “new” compliance criteria have proven, and practical experience with compliance monitoring is discussed.
Acoustic methods for data transmission across a room.
Authors: Hutchins David , Li Chuan , Green Roger
Published: July 2011

Acoustic signals have been used to transmit signals indoors across a room with a data rate which allows many applications. Frequencies in the range 100 kHz–1 MHz have been used, together with modulation techniques used in modern digital wireless communications. It is shown that signals can be transmitted across several meters distance using sources and receivers based on capacitive (electrostatic) designs, where the required bandwidth is avaialable. It is also demonstrated that demodulation techniques can be successfully applied to retrieve the original data from the received signal. The approach has many uses, especially for secure in-room digital communications.
Documenting the soundscape of a historic working farm.
Authors: Siebein Keely M.
Published: July 2011

A working 1880’s farm is the focus of an exploration to provide an acoustical record of historical sounds that once comprised the soundscape. Long term acoustical measurements (including overall A-weighted sound levels, minimum and maximum levels taken once per minute, SEL, statistical metrics, and day/night sound levels), short term measurements (including overall A-weighted and 1/3 octave band sound levels of specific acoustic events), WAV recordings, and video footage are used to analyze typical historic sounds of the farm including a blacksmith forging metal, woodworkers using hand tools to carve wood, children playing period games, lumberjacks shaping logs for buildings, and ranchers cracking whips to drive animals. These historic sounds are documented, along with sounds of the 21st century, including automobile traffic from nearby roadways, aircraft overflights, and various modern machines used in the park to provide a detailed analysis of what a typical rural southern farm soundscape may have sounded like over 100 years ago.
Techniques in sound propagation modeling for noise impact assessment in three-dimensionally variable environments.
Authors: Austin Melanie E. , MacGillivray Alexander O.
Published: July 2011

Sound generated in the ocean by human activities has the potential to be disturbing or harmful to marine fauna. Environmental assessments of offshore industrial activities must often include noise impact studies for regulatory approval. Such noise impact studies examine the spatial extent of underwater noise using a computer model to estimate the propagation loss between a noise source and a grid of surrounding receiver points, providing the information necessary for the effective assessment and management of anthropogenic marine noise. Models based on the solution of the parabolic form of the wave equation can be used to generate very accurate acoustic field estimations in range-dependent environments. While parabolic equation (PE) codes can also be configured to accurately handle three-dimensional (3-D) propagation effects, the numerical techniques they require can be very computationally intensive. Pseudo-3-D PE solutions are typically computed to prevent prohibitively long model run times. The implications of applying different PE modeling techniques for environmental noise impact assessment in coastal environments are presented. The factors considered include the neglect of or inclusion of 3-D propagation effects in the model, and the consideration of directional noise sources in 3-D variable environments.
Two-dimensional localization of walruses in shallow water using a ray-tracing model.
Authors: Mouy Xavier , Zykov Mikhail , Martin Bruce S.
Published: July 2011

Pacific Walruses summering in the eastern Chukchi Sea produce underwater sound pulses called knocks. Chukchi Sea is a flat shallow environment that favors reflections of the sound on the surface and bottom interfaces. In acoustic data collected in the Chukchi Sea in 2007, the knocks emitted by walruses were recorded with up to seven bottom/surface reflections. Relative multipath arrival times (RMATs) provide very valuable information that can be used to define range and depth of the vocalizing animal. This paper demonstrates a method for localizing walruses based on a ray-tracing model. BELLHOP was used to simulate the RMATs received by a hydrophone for hypothetic acoustic sources located at different range and depth positions. The model assumed flat bathymetry, a source emitting at 1 kHz and a single range-independent sound speed profile per monitoring station. An index representing the match between the measured echoes and the model was calculated at each point of the model grid. The highest matching index indicated the depth and range of the walrus. Several walrus tracks were extracted from the data. Localization results allowed defining diving patterns, depths of bell-like calls, source levels estimates, knock production rate, and swimming speed of monitored walruses.
High intensity focused ultrasound for cyclocoagulation: From transducer design to early clinical trials.
Authors: Lafon Cyril , Aptel Florent , Charrel Thomas , Birer Alain , Chavrier Françoise , Chapelon Jean-Yves , Romano Fabrice , Denis Philippe
Published: July 2011

Many therapeutic procedures have been proposed for treating glaucoma, which remains refractory in many cases. Although HIFU treatments were successful [Lizzi et al.], laser-based approaches proved to be more clinically feasible. The new proposed ultrasonic device aims to perform a conformal, partial, and fast thermal ablation of the ciliary bodies for reducing the production of aqueous humor and intraocular pressure (IOP). The design of the device was based on numerical simulations and consideration of anatomical constraints. The device has six cylindrical 21 MHz transducers for modulating and producing sharp zones of ablation. The applicator was characterized in vitro and tested in vivo in rabbits. Exposure conditions were set to 6 W/cm2 for 3 s applied sequentially on the transducers. A clinical pilot study was then started to assess the feasibility, the tolerance, and the efficacy of the treatment of refractory glaucoma. Results of in vivo experiments showed significant decrease of IOP and no adverse effects on histology. Eight patients were treated with similar exposure conditions. The absence of side-effects and the significant decrease of IOP, from 36.2 to 25.2 mm Hg 6 months after treatment, proved the clinical relevance of this new device for treating refractory glaucoma. [Work funded by EyeTechCare SA.]
Electronic enhancement of the directional response of a micromachined biomimetic optical microphone.
Authors: Bicen Baris , Degertekin Levent , Su Quang , Cui Weili , Miles Ronald N.
Published: July 2011

A silicon micromachined biomimetic optical microphone has been recently demonstrated to have directional response and low noise [J. Acoust. Soc. Am. 125(4), 2013–2026 (2009)]. In this microphone, the motion of one end of the pivoting rectangular diaphragm is detected using an integrated optical interferometer and each end can be actuated using separate electrostatic actuators. This configuration enables one to selectively enhance either the directional, anti-symmetric rocking mode or the omni-directional symmetrical second vibrational mode of the diaphragm in two separate active feedback loops. A circuit model with two electrical ports to actuate each side of the diaphragm, and two acoustic ports to drive each mode has been developed to illustrate the electronic method. The model includes the effect of the air medium and the backside cavity through mechanical impedances which are verified through measurements. With the two-sided active feedback scheme, the model predicts significant improvements in the directional response resulting in more than 10-dB improvement in the residual intensity index when the microphone is used for gradient measurement in an intensity probe.
Modeling of frequency responses for arbitrary earphone designs.
Authors: Du Yu
Published: July 2011

To meet a certain frequency response, the earphone design process often involves selecting receivers, style and dimensions of sound tubes, and damping used in the sound tubes. Currently, this is largely a trial-and-error procedure, especially when multiple drivers are used. Since there is lack of a reliable modeling method, the response characteristics of current earphone designs rely heavily on the experience of the designers’ experiences. This study is concerned with the development of a modeling approach to aid the earphone design process. During the model development, it is assumed that the earphone response is measured inside an earcoupler (e.g., IEC 60711). Furthermore, it is also assumed that the dynamic characteristics of the selected receiver(s) and the impedance of the terminal earcoupler are known. The model predicts the response based on the selected structural features including the sound tubes and damping values between the receiver(s) and the earcoupler. Both lumped-parameter modeling and finite-element modeling methods are discussed. The predictions are then compared with experimental results. It is shown that the model results reasonably match the measurement data. It is concluded that this modeling approach can give insights before building physical prototypes, thus significantly increasing the efficiency of the earphone design process.
Demonstrating the effect of air temperature on wind instrument tuning.
Authors: Worland Randy
Published: July 2011

Wind instruments are known to play out of tune when the air temperature is well above or below room temperature, as may occur during outdoor performances. Because the speed of sound in air increases with rising temperature, brass and woodwind instruments tend to play sharp when the air is hot and flat when the air is cold. A simple demonstration of this effect is shown using PVC pipes. Temperature differences sufficient to make the effect audible are easily obtained using ice water and hot tap water. The demonstration is safe, inexpensive, and easy for students to perform. Extensions to the basic procedure are described, including the use of greater temperature extremes and comparison of measurements with theory. The demonstration is suitable for students of many different levels, using either a qualitative or quantitative approach.
A tessitura-gram for singers.
Authors: Titze Ingo R.
Published: July 2011

In singing, tessitura refers to the pitch range and median pitch level of a song. Physiologically, a singer has his own tessitura. It is shown here that a voice range profile, which is a plot of intensity range or subglottal pressure range versus fundamental frequency, can be used to quantify the tessitura of a singer. Finding the best match between the singer’s tessitura and the vocalist’s tessitura can help performers predict their success on certain compositions that cannot be transposed or to find the ideal transposition. Concepts of vocal endurance and dynamic range are also discussed in light of the tessitura-gram.
The realization of rising tone contours in sung Cantonese.
Authors: Schellenberg Murray H.
Published: July 2011

Singers in tone languages are often thought to rely entirely on song melody to realize the tonal speech melody of the language. There is, however, some limited evidence that singers directly modify vowel F0 corresponding to lexical tone while singing. This paper analyzes the acoustic output of ten Cantonese singers singing a specially composed song to test whether singers adjust their performances to reflect mismatches between speech melody and song melody. It is found that singers include the dynamic portion of rising contour tones (falling tones were not included in this study) but that they do not adjust their performance to mark register components of tone.
Multipitch analysis with specmurt based on the sparseness of the common harmonic structure pattern.
Authors: Nishimura Daiki , Nakashika Toru , Takiguchi Tetsuya , Ariki Yasuo
Published: July 2011

A novel multipitch analysis based on specmurt with the sparseness of the common harmonic structure pattern is presented. The conventional specmurt analysis is based on the idea that a fundamental frequency distribution is expressed as a deconvolution of the observed spectrum by the common harmonic structure pattern. However, it is considered impossible to obtain the strictly correct model of the common harmonic structure since harmonic structures can slightly vary depending on the pitch. Therefore a new method to analyze the fundamental frequency distribution without modeling the common harmonic structure is proposed. In this method, many possible fundamental frequencies are prepared using observed spectrum peaks, and harmonic and nonharmonic structures corresponding to them are obtained by the deconvolution of observed spectrum. Then, based on the sparseness, L1 or L2 norms are applied to only the appropriate harmonic structures in order to obtain a correct harmonic structure. The experimental result shows the effectiveness of our proposed method.
A computational method for evaluating the installation effects of axial flow fan system noise.
Authors: Bibb John S.
Published: July 2011

Fan noise has become a significant source of noise in many environments. In product design the desire for low fan noise is often hindered by insufficient data in the design phase. In this work, a noise prediction scheme for low speed fans with significant inflow distortion was developed. Basic design parameters such as thrust, torque, blade shape, and blade thickness are used to predict a baseline noise signature. Flow disturbances from simple common shapes in the flow path are approximated and used to determine the noise level produced for a fan that is installed in a particular geometry. The inputs to the program are restricted to commonly available information that can be determined early in the design cycle. The process has been verified with an experimental setup in an anechoic chamber. The results of the experiment and the prediction from the program agree within 3 dB over a wide range of angles for the first two blade passing frequencies and a reasonable range of broadband noise.
Investigation of user complaints of sound masking delivered from underfloor air distribution grilles.
Authors: Rogers Mark
Published: July 2011

A LEED-Gold certified government building includes six floors of open-plan office space that are equipped with electronic sound masking delivered from a raised floor having under-floor air distribution (UFAD). Results of user polling show mixed results for acoustic satisfaction, with significant complaints about speech privacy, and noise from the systems interfering with users’ ability to work. This research focuses on this dissatisfaction, the general conflict between speech privacy ease of verbal communication, and acceptance of noise-generating treatments. Little research has been done on masking delivered via UFAD, so it was also desired to further the understanding of this design as part of a larger research program by the Federal government on Green Buildings. Specific objectives were to develop and test possible remedies for this system, and improve planning of future facilities that may have masking via UFAD. On-site measurements of masking and HVAC spectra, as well as noise reduction and observations for various conditions, were made. Post-measurement data analysis was conducted, and experimental remedies were developed and tested. The results and recommendations will be presented.