bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound choices: Designing a pipe organ to suit its acoustical environment
Authors: Bellocchio Matthew M.
Published: May 2014

A key to the effectiveness of any pipe organ is to design it to be acoustically compatible with its environment. Churches and concert halls all vary in size, plan, seating arrangement, resonance, reflectivity, and reverberation. A successful instrument should have a balanced sound in the room throughout its frequency range, be capable of both warmth and brilliance, and have a variety of tonal resources suitable for both solo performance and accompaniment. The choices an organbuilder makes regarding placement, physical size and layout, tonal specification (choice of stops), pipe materials and dimensions, wind pressures, and voicing style, all contribute to an instrument's tonal signature and acoustical effectiveness. These decisions are usually based on historical precedents, traditional knowledge, personal taste, and experience. The four-manual Casavant organ, Opus 3145, in the Cathedral of Saints Peter and Paul in Providence, Rhode Island, illustrates Lawrence Phelps' tonal design for a heroically sized mechanical action instrument intended for a large, acoustically live space. This organ, built in 1972 at the height of the Baroque Revival period in American organbuilding, was intended to be a legacy instrument for the designer, the builder, and the client.
The integration of acoustics in construction management education
Authors: Philipp Norman H.
Published: May 2014

An overview of the importance and need for acoustics and proper noise control mitigation in assemblies and during construction being integrated into construction management education. Items discussed include the impact of noise on a construction site, workers, and neighboring areas; importance of considering acoustical considerations in project scheduling; and methodologies for enabling student understanding of acoustics in construction.
Mitigation of construction noise at operating hospital and university facilities
Authors: Standlee Kerrie G.
Published: May 2014

Hospitals and universities often have occasions where new or remodeling-related construction must occur during times when existing facilities are in use. Noise caused by construction at an active facility often requires that steps be taken to minimize the impacts associated with the construction. This paper discusses the findings made during the course of several projects undertaken by Daly-Standlee & Associates, Inc., to determine mitigation measures that could be used to minimize noise impacts from construction at operating hospital and university facilities.
On the importance of experienced acoustical inspectors during and following the construction process and installation of noise mitigation measures
Authors: Hale Marlund E.
Published: May 2014

During the installation of recommended noise mitigation measures that appear on architectural drawings or that are presented in project acoustical reports, demolition, renovation, office building, institutional facilities, apartment buildings, and condominium construction trades may or may not omit and/or improperly install the recommended noise control systems. This paper presents several examples of such improper practices that, had they not been discovered, would have resulted in significant reductions in the planned noise control performance. These cases result in undesired living and/or working conditions. The selected examples of such construction problems are discussed and successful remedies are presented, some of which avoided threatened litigation.
Fun with foggers
Authors: Holt R. Glynn
Published: May 2014

Many physical acoustics phenomena can be demonstrated with a so-called “pond fogger.” The easy availability and affordable price of these acoustic transducer systems allows one a lot of freedom in the demonstrations one can do. Three phenomena, acoustic streaming, standing waves, and Faraday waves, will be demonstrated in this talk. The audience will be invited to propose and investigate others during the talk.
Non-electric sensing, amplification, and presentation of sound using fluidic laminar flow technology
Authors: Scanlon Michael V.
Published: May 2014

This briefing will describe and demonstrate fluidic-based sound reception, amplification, and pneumatic headphone presentation to the listener. Fluidics is non-electronic and uses laminar proportional amplifiers and fluid-flow technology to demonstrate a sensitive “microphone” due to its massless diaphragm (laminar jet of low-velocity air) and perfect impedance matching to the propagating medium (also air). Many years ago the U.S. Army developed a system called the Individual Soldier Operated Personal Acoustic Detection System (ISOPADS) that utilized this fluidic technology to enhance and extend the Soldier's listening range. This demonstration system will let people point a small parabolic dish and listen around the room using a pneumatic headset. It makes for a fun demo, especially when participants understand that they are listening to a non-electronic system that uses only air.
Investigation of capillary wave formation on water jets with internally propagating ultrasound
Authors: Banda Nikhil M. , Douglas Offin , Peter Birkin R. , Timothy Leighton G.
Published: May 2014

The formation and control of capillary waves on jets are of importance in applications such as ink-jet printing, atomization of fuel, etc. External control of jet breakup processes is generally based on the ultrasonic atomization principle (used on jets of diameter in micrometer order) with transducers placed on nozzle tips. The present work investigates the formation of capillary waves and subsequent jet breakup on 10 mm and 15 mm diameter water jets with ultrasound propagating at either 121 kHz or 135 kHz. Experimental observations of the jet breakup process with a high speed camera are reported. The input signal to the transducer was controlled to investigate the formation and growth of capillary waves, leading to the breakup of the jet. It was observed that once the waves are formed on jet surface, they grow in size leading to a necking zone. Once necking zone is formed, the capillary waves then just propagate along the jet (with the flow) with no further growth in their amplitude. Spraying of the jet was also observed at the same time. The measurement of capillary wavelength and jet breakup length are measured and presented in an attempt to understand the nature of the breakup process.
“The data are the data”: Tino and the importance of empirical observation
Authors: Akeroyd Michael
Published: May 2014

I was a postdoctoral scientist in Tino and Les' binaural psychophysics lab from 1999 to 2001. One of my abiding memories from my time then was the motto “the data are the data”: in almost every discussion we had on science, Tino would illustrate a point or an idea by reference to a graph of data. Often the graphs were obscure and unjustly ignored by later scientists—but Tino, with his encyclopedic memory for data, would know just where to look for it in a issue of JASA or an mimeographed manuscript. It is a lesson I have always remembered: that science is fundamentally based on accurate measurements of phenomena, and, though the explanations and interpretations may change, the data are always the data, and they are not undone or falsified by the passage of time. This talk will illustrate the argument with data—after all, what else?—from Tino's, mine, and others' papers. [Work supported by the Medical Research Council and the Chief Scientist Office, Scotland.]
Different ears
Authors: van der Heijden Marcel
Published: May 2014

Most models of binaural processing assume identical inputs from the two ears to the binaural processing stage. From the high accuracy of binaural processing one may expect slight deviations from perfect symmetry of its inputs to affect performance. Such deviations may be systematic such as the tuning differences postulated by stereausis models. Alternatively, asymmetries may simply result from imperfections in cochlear frequency tuning or from “sloppy wiring” projecting to the binaural cells. I will analyze how different types of interaural asymmetry affect predicted performance in psychoacoustic tasks and discuss physiological evidence for imperfect symmetry of the monaural inputs.
Microscale granular metamaterials
Authors: Boechler Nicholas
Published: May 2014

Locally resonant metamaterials and granular media are both known to drastically affect acoustic wave propagation. However, there are thus far few examples of such materials which have microscale elements and are designed to control acoustic waves with megahertz frequencies or greater. In this talk, I will discuss our recent work at the intersection of these two types of materials, in which we explored the interaction of megahertz-gigahertz frequency surface acoustic waves with a self-assembled metamaterial composed of microspheres adhered to an elastic substrate. I will present our theoretical model and describe our photoacoustic experiments, in which we used transient-grating spectroscopy to measure the acoustic dispersion of the system. Finally, I will also discuss several potential applications of these novel materials such as signal processing and biosensing devices.
The “Carey Number” continued—Mechanisms governing the horizontal array coherence length in shallow water acoustics
Authors: Lynch James F. , Duda Timothy F. , Lin Ying-Tsong , Newhall Arthur
Published: May 2014

The use of simplified “feature models” (geometric idealizations of specific, isolated ocean features) for coastal oceanographic features can allow one to calculate acoustically useful quantities approximately and even generate analytic forms for them. Feature models for coastal fronts, eddies, internal tides, linear and nonlinear internal waves, and spice are presented, and the scattering of sound from these objects is calculated. This allows one to estimate the useful quantity Lcoh, the horizontal coherence length that represents a physical limit for array signal processing. Continuing work on calculations of Lcoh, including source/receiver motion, will be presented. [Work sponsored by the Office of Naval Research.]
J. Christopher Jaffe: Scientist and friend
Authors: Beranek Leo L.
Published: May 2014

Chris Jaffe is acclaimed for his original designs of spaces for the performance of music. It has been this author/s pleasure to discuss his many projects and to hear concerts in his four best known halls: Severance Hall in Cleveland, Ohio; Bass Performance Hall in Fort Worth, Texas; the Concert Hall at the Kennedy Center in Washington, D.C.; and the Sala Nezahualcoyotln in Mexico City. Chris took great pleasure in teaching others the field and was the leader in establishing the Concert Hall Research Group that took data in many halls and held seminars for acousticians at all levels. Other facets in his life will be discussed.
Jaffe's signature: Science, with art
Authors: Case Alexander U.
Published: May 2014

I am one of a handful of students claiming the title, “Chris Jaffe's first graduate student,”—but I really am the first! I found at Rensselaer Polytechnic Institute a program that reflects his priorities. We did not just study the physics of room acoustics and make measurements in built spaces. We worked side by side with architects, engineers, electronic musicians, and other artists. Acoustics was not an isolated achievement. It was always part of a collaborative effort with other ambitious disciplines. We built things—big, awe-inspiring things—visually stunning, sonically thrilling. I found myself studying, measuring, and recording in all kinds of spaces, from concert halls in Texas to subway stations in New York. Thanks to Dr. Jaffe's leadership, were always doing, growing, learning, and laughing.
Chris Jaffe: Youthful golden years
Authors: Markham Benjamin , Rosenberg Carl
Published: May 2014

From 2009 until his demise—roughly 50 years after his entrée into the acoustics field—Chris Jaffe was a valued partner in the Acentech Studio A team. We will share the manner in which his mentorship and guidance informed us and our profession. His self-deprecating humor could not disguise his intense knowledge, broad experience, willingness to help mentor junior staff, and engagement in new endeavors. He imbued his acoustics consulting “golden years” with youthful vigor, and he accomplished much: he finished his book, consulted on projects, shared back stories, enlivened our parties, introduced us to his friends and his manner of collaborating with them, and made an indelible imprint on both the content and style of our performing arts practice. Our presentation will share these experiences as life lessons for success and respect in our profession.
Chris Jaffe's three A's
Authors: Holzman Malcolm
Published: May 2014

The first A is for Academia: The importance Chris Jaffe put on education as a foundation and a concentration for his career. The second A is Acoustics: A lifespan focused on propelling the science and art of architectural acoustics in the civic and academic presentations of music, theater, and dance. The third A is Adirondacks: His affection and attachment to the Adirondacks were a measure of the man.
Stimulus-frequency and response timing in clouded leopards: Evidence for inner ear adaptation
Authors: Walsh Edward J. , Shera Christopher A. , Abdala Carolina , Robertson Heather E. , McGee JoAnn
Published: May 2014

Unlike the inverse relationship between response timing (latency) and stimulus frequency commonly observed in other fields, the relationship in species belonging to the Pantherinae subfamily is more complex. Although an inverse relationship exists between neural timing and low frequency stimuli (between 0.5 and 1–2 kHz), the relationship for frequencies greater than 2 kHz breaks from this pattern and is best described by a positive-going parabola-like curve with a maximum value in the vicinity of 8 to 16 kHz in representatives of the Pantherinae lineage studied thus far. In clouded leopards the local maximum is near 8 kHz. This general latency-frequency pattern has been confirmed in tigers and appears to hold for jaguars and lions. Clouded leopards (Neofilis nebulosa) branched directly from the Panthera lineage approximately 6 million years ago. This phylogenetic proximity to Panthera makes the genus Neofilis particularly interesting in relation to the response timing question. The outcome of previous efforts to determine the cochlear site of origin of short latency responses to lower frequency stimuli in the tiger were consistent with the existence of a basal turn timing adaptation. The implications of such adaptation in clouded leopards will be considered.
A comparison of hees and haws: Donkey, Grevy's zebra, and African penguin
Authors: Browning David , Scheifele Peter
Published: May 2014

A surprisingly few creatures bray (vocalizing during both breath in and breath out). It is not apparent why this is so or what advantage it gives those that do. This is a comparison of the technique and acoustic content for the three most well-known brayers. Donkeys (Equus asinus) have the most rich or raucus bray, depending on your point of view. Some donkeys start with a hee (breath inflow) and others with a haw (breath outflow), generally continuing until they are out of breath. The Grevy's zebra (Equus grevy) shares the perrisodactyl ability to vary frequency during vocalization but it appears to be a strained activity, resulting in a scaled down version of the donkey bray. The African penguin (Spheniscus demersus) has the most uniform and tonal haw, in most cases preceded by a series of short hees, apparently to increase breath.
Molecular subtyping of colorectal cancer using high-frequency ultrasound
Authors: Holman Alexis M. , Doyle Timothy E.
Published: May 2014

Previous studies have shown high-frequency (HF) ultrasound (10–100 MHz) may be sufficiently sensitive to detect and differentiate between both the histopathology and molecular subtypes of breast cancer. In order to explore other uses of HF ultrasound in real-time cancer diagnoses, two colorectal carcinoma cell lines were investigated: HT-29 and SW-620. This experiment tested the sensitivity of HF ultrasound on HT-29 and SW-620 and its ability to differentiate between the two lines. Subtypes of colorectal carcinoma have not been defined, but the morphology of these cell lines indicates that they may possess different molecular subtypes. Cell lines were grown as monolayer cultures and promptly tested with HF ultrasound using a single-element (50 MHz, 6.35-mm) ultrasonic immersion transducer. Ultrasound techniques and conditions were similar to previous breast cancer monolayer tests. Preliminary results indicate the cell lines produce different waveform and spectral signatures. The ability to differentiate between the two cell lines will both broaden the application of HF ultrasonic testing, and provide a method to define colorectal carcinoma subtypes. More cell lines will be tested in an effort to clearly define molecular subtypes of colorectal carcinoma. Defining subtypes will allow for more personalized diagnoses and treatment options for colon cancer patients.
Cough monitoring for pulmonary tuberculosis using combined microphone/accelerometer measurements
Authors: Fan Jingqi , Comina German , Gilman Robert , Lopez Jose , Tracey Brian H.
Published: May 2014

A laboratory-free test for assessing recovery from pulmonary tuberculosis (TB) would be very helpful in regions of the world where laboratory facilities are lacking. Our hypothesis is that analysis of cough sound recordings may provide such a test, as recovering patients should cough less frequently. We have carried out several studies on cough data from a cohort of TB patients in Lima, Peru [Larson et al., PLOS One]. Our previous work provides a foundation to support larger-scale studies of coughing rates over time for TB patients undergoing treatment, but it only used recordings from lapel microphones. For the current study, we use an additional channel recorded by a throat-mounted accelerometer. The accelerometer only responds to patient-generated noise events and thus provides robustness to background noise in the environment. We describe algorithm development for cough data analysis using combined microphone/accelerometer measurements, and compare several event detection and classification strategies. We show that adding the accelerometer improves performance on detection and classification.
Approximately 20 Hz plus harmonics amplitude modulated acoustic emissions from a 1.6 MW wind turbine, measurements versus predictions
Authors: Dooley Kevin A. , Metelka Andy
Published: May 2014

A recently presented hypothesis and model relating to the generation of spinning modes from wind turbines, as a direct result of acoustic interaction involving the tower, also predicts ~20 Hz plus harmonics low frequency amplitude modulated acoustic emissions as a side effect of the acoustic interaction. The low frequency sound is expected to propagate at measurable amplitudes to the far field (1km to 2 km). Measurements focused on the ~20 Hz amplitude modulated fundamental and harmonics made at different angles relative to the rotor plane at very close range, and at greater distances are presented. The measurements are compared to predictions based on the tower acoustic interaction hypothesis.
Equivalent sources method for supersonic intensity of arbitrarily shaped geometries
Authors: Valdivia Nicolas P.
Published: May 2014

Supersonic acoustic intensity is utilized to locate radiating regions on a complex vibrating structure. The supersonic intensity is obtained by a special process that removes the subsonic waves from the near-field acoustical holography measurement. The filtering process is well understood for separable geometries, but unfortunately, there are few results for arbitrarily shaped objects. This work proposes a methodology based on a stable invertible representation of the radiated power operator. The power operator is approximated numerically by the equivalent source formulation and the appropriate complete spectral basis is employed to form the stable invertible operator. The operator is formed with the most efficient radiation modes and these modes are utilized to obtain the supersonic solution for the near-field holographic problem. This concept is tested using numerically generated data in a spherical geometry and the results are validated with the spherical harmonic, supersonic filter. Finally, a vibrating ship-hull structure provides a physical example for application and validation of the proposed methodology in a more complex geometry. [This work was supported by the Office of Naval Research.]
Investigations on psychoacoustical and non-acoustical moderators for annoyance evoked by wind turbine noise
Authors: Schmidt Leonid , Fiebig André
Published: May 2014

In 2012, in total around 23 000 wind turbines are installed on land in Germany. These wind turbines are important to achieve a change in Germany's current energy policy gaining more energy from renewable resources. However, current research underlines that the noise of wind turbines causes noise annoyance and provoke complaints. The sound characteristics of wind turbines depend on many different variables, e.g., type of wind turbine and wind speed. Unfortunately, only little is known about the specific noise characteristics, which are mainly responsible for noise annoyance. Therefore, laboratory experiments are carried out to identify the most annoying noise characteristics of wind turbine noise. The laboratory experiment includes an evaluation of different sounds from wind turbines, manipulated wind turbine sounds, and sounds from other noise sources. The work intends to improve the understanding about the role of psychoacoustic parameters going beyond equivalent continuous sound level. Additionally, the relevance of non-acoustical factors for annoyance caused by wind turbine noise is investigated by interviewing extensively the test subjects.
Harsh environment sensors: Aircraft and oil field applications of electromagnetic and acoustic technologies
Authors: Furlong Edward R.
Published: May 2014

There is an old saying that what can be measured can be improved. However, measuring the key parameters in aircraft engines that drive efficiency and emissions is very difficult. This is even more the case in oil field applications, where extremely high pressures and temperatures are commonly encountered. But the benefits to society of reduced emissions (carbon, pollutants, and noise) and improved oil and gas recovery are tremendous. The task for instrument manufacturers is to develop sensors that are both reliable and cost effective. Recent advances in the application of electromagnetic and acoustic technologies are described for measuring temperature, pressure, flow, and composition in harsh environments. The sensors range from inductively and optically coupled ceramic and silicon devices to ultrasonic and SAW devices packaged with high temperature electronics to fiber optic systems. These sensors are now being deployed on new airframes, engines, deep water wells, horizontal tight shale formations, and high temperature/high pressure wells.
A resonance technique for the acoustic characterization of liquids in harsh environments
Authors: Sturtevant Blake
Published: May 2014

Accurate knowledge of a liquid's acoustic properties, such as sound speed as a function of temperature and pressure, is important for both basic and applied science. For basic science, sound speed is important for constraining thermodynamic equations-of-state as well as determining elastic nonlinearity parameters. From an applied perspective, sound speed can be used together with other properties to monitor fluid temperature, pressure, and composition. There are important applications, such as in oil/gas or geothermal well characterization, where it is desirable to measure sound speed in liquids in well bore under high pressure, high temperature, and in corrosive environments. However, few experimental sound speeds have been previously reported above 100°C even in liquids as common as water. This talk focuses on the development of a portable, rugged, resonance-based measurement cell for high precision (better than 0.1%) in-situ measurements of sound speed in high temperature, high pressure, and corrosive liquids. As an example of the technique, experimentally determined sound speeds in liquid water up to 250°C and 3000 psi will be presented. Acoustic nonlinearity in water, as determined from sound speed as a function of temperature and pressure, will also be discussed.
Development, qualification, and performance validation of an optical differential pressure sensor for downhole permanent monitoring applications
Authors: Dunphy James R. , Unalmis Omer H. , Taverner Domino
Published: May 2014

This paper describes the development, qualification, and performance validation of an optical differential pressure (DP) sensor for the high-pressure and high-temperature downhole environment. The current implementation of measuring DP in downhole applications is based on the calculated difference between two static pressure sensor measurements with high uncertainties. A true DP sensor is superior in comparison due to the decreased uncertainty both in measurement and component levels. This translates to better performance in system level measurements such as flow. A development program was launched in 2007 to build an optical DP sensor targeted for two main applications: standalone use in single-phase or auxiliary use in multiphase flow measurement systems. Several prototypes have gone through multiple design phases and qualification test programs including mechanical shock and vibration tests, thermal tests, hot vibration tests, short-term stability and long-term endurance tests. The sensor was then integrated with a Venturi and tested in a single-phase flow loop to validate its performance against an electronic DP sensor and an electromagnetic flowmeter. Results suggest that optical DP sensor performs better than the electronic DP sensor in measuring differential pressures, and is on a par with the electromagnetic flowmeter.
Resonance ultrasound spectroscopy measurements of sandstone at high temperature
Authors: Davis Eric S. , Sturtevant Blake T. , Sinha Dipen N. , Pantea Cristian
Published: May 2014

Deep underground wells, such as those of interest to the oil and gas as well as geothermal industries, are often found in large sandstone formations. In order for drilling, enhancement, and advanced engineering techniques such as hydraulic fracturing to be efficient and successful, the mechanical properties of materials that make up the reservoir must be accurately known. We have used resonant ultrasound spectroscopy (RUS) to determine the physical properties of Berea Sandstone, such as the elastic moduli. In contrast to single crystals or high quality polycrystalline samples, the porous and attenuating nature of sandstone makes an acoustic study of sandstone very challenging. Additionally, the sandstones must be studied at high temperatures in order to simulate conditions that are found in the field. We will present our work on the temperature dependence of the elastic moduli of sandstone (between room temperature and 205 °C.) Our measurements show that Berea sandstone is a very soft material with a bulk modulus of about 6 GPa as compared to 76 GPa for aluminum. Furthermore, a ~10% softening was observed with decrease in temperature, down to a temperature of 110°C, followed by a ~7% hardening down to ambient temperature.
The propagation of sound above and within a hardbacked rigid porous layer
Authors: Tao Hongdan , Tong Bao N. , Li Kai Ming
Published: May 2014

The present paper examines, theoretically and experimentally, the sound field in the vicinity of a non-locally medium due to an airborne source. The non-locally reacting medium is characterized by a porous layer of finite thickness which is placed on a perfectly reflecting plane. According to an asymptotic analysis, the total sound field within the rigid porous medium consists of two components. Each of these two components can be represented by an integral expression. They can then be evaluated by a standard saddle path method to obtain a uniform asymptotic solution. Numerical validation with wave-based numerical schemes demonstrates the accuracy and computational efficiency of the derived asymptotic formula. Additional validation is provided through indoor experimental data obtained by using a layer of glass beads for modeling the rigid porous medium. When the receiver is situated within the porous layer near the perfectly reflecting plane, experimental measurements and theoretical predictions suggest that the interaction of the refracted wave with the perfectly reflecting plane has a significant impact on the total sound field. Experimental data and numerical simulations also indicate that it is rather difficult to distinguish the results between a thin rigid porous layer and a semi-infinite rigid porous medium for an airborne receiver.
Identifying otosclerosis with battery of aural acoustical tests of absorbance, group delay, reflex threshold, and chirp-evoked otoacoustic emissions
Authors: Keefe Douglas H. , Archer Kelly L. , Schmid Kendra K. , Fitzpatrick Denis F. , Feeney M. Patrick , Hunter Lisa L.
Published: May 2014

This study evaluated the clinical utility in diagnosing otosclerosis with aural acoustical tests of absorbance, acoustic reflex threshold (ART), and otoacoustic emissions (OAEs) in 23 normal-hearing (NH) ears, 12 ears diagnosed with otosclerosis (OS), and 13 ears after surgical intervention (SU) for otosclerosis. Subjects received audiometric evaluations, and tests of ipsilateral/contralateral ART, pressure reflectance (0.25–8 kHz) parameterized by absorbance and group delay at ambient pressure and at swept tympanometric pressures, and chirp-evoked OAEs (1–8 kHz). ARTs were measured using tonal and broadband noise activators, based on differences in wideband absorbed sound power before and after activator presentation. For NH compared to OS ears, mean ambient absorbance was larger at 4 kHz; mean tympanometric absorbance had larger peak-to-tail differences at low and high frequencies. Probe-to-eardrum length was estimated using group delay at the frequency of the minimum absorbance above 2 kHz, and combined with acoustically estimated area to calculate wideband compensated admittance at the eardrum. Absorbance and compensated group delay revealed complementary information on middle-ear function. Typical OS and SU ear tests showed absent TEOAEs and ARTs, reduced absorbance in OS ears, and anomalous reflectance <1 kHz in SU ears. Other middle-ear conditions showed different patterns of test-battery responses. [Research supported by NIH.]
Comparisons of reflectance measurements across measurements sessions, instruments, and ages
Authors: Voss Susan E. , Abur Defne , Kassaye Hiwot , Horton Nicholas J.
Published: May 2014

Wideband acoustic immitance measures (WAI) are an active area of research aimed at the development of an objective and noninvasive audiometric test that can reliably identify a range of middle-ear disorders. This work compares repeated WAI measurements (absorbance and its closely related quantity power reflectance, in particular) made on normal hearing subjects. In particular, measurements were made on the left and right ears of nine subjects ages 19–22 and seven subjects ages 41 to 47. Each subject returned for repeated measurement sessions between four and eight times. At each measurement session, WAI was measured using two distinct FDA-approved devices: HearID from Mimosa Acoustics and Titan from Interacoustics. This presentation will compare the WAI measurements between two distinct age groups, the two distinct instruments, and across measurement sessions. Additional analyses will be presented to determine if assumptions about ear-canal areas might explain differences between the systems from Mimosa Acoustics and Interacoustics.
Estimating the residual ear canal contribution to complex acoustic reflectance measurements using pole-zero fitting
Authors: Robinson Sarah , Thompson Suzanne , Allen Jont
Published: May 2014

For diagnostic acoustic measurements of the middle ear, the residual ear canal (REC) between the probe and tympanic membrane (TM) is a significant source of non-pathological variability. Tympanometry measures the TM compliance as a function of canal static pressure, at a single frequency (226 Hz). Alternatively, wideband reflectance is measured at ambient pressure, over a large frequency range (0.2–6.0 kHz). To account for the REC effect, tympanometry assumes that the compliance tends to zero at large static pressures, which may not be a valid assumption (Rabinowitz, 1981), whereas reflectance assumes that the REC contributes a lossless delay. Previously, the authors developed a method to parameterize complex reflectance measurements using pole-zero fits, which may be factored into all-pass and minimum-phase components. The lossless all-pass component approximates the unknown REC delay, while the low-frequency TM compliance may be estimated from the minimum-phase component. Using this approach, we evaluate middle ear static pressure data from a controlled study of cadaver ears (Voss, 2012) and an in vivo study in which subjects were trained to induce negative middle ear pressure, as well as controlled syringe measurements. Our results indicate that the TM compliance is not zero at the static pressure extremes measured under tympanometry.
Investigating stream segregation and spatial hearing using event-related brain responses
Authors: Wang Le , Messier Samantha , Bressler Scott , Sussman Elyse , Shinn-Cunningham Barbara
Published: May 2014

Several studies have used auditory mismatch negativity (MMN) to study auditory stream segregation. Few of these studies, however, focused on the stream segregation that involves spatial hearing. The present study used MMNs to examine the spatial aspect of stream segregation. Traditional oddball streams were presented in a passive listening paradigm, either in isolation or in the presence of an interfering stream. The interfering streams were engineered so that the deviants were not unexpected if the two streams were heard as perceptually integrated. Interfering streams were either spectrally distant from or close to the oddball stream, and were also spatially separated from the oddball stream. The deviant stimuli differed from the standards in perceived spatial location. For comparison, the MMN paradigm developed by Lepistö et al. (2009) using intensity deviants was repeated on the same group of subjects. For both paradigms, the MMN was strongest when the oddball stream was presented in isolation, less strong but present when the two streams were spectrally separated, and not observable when the streams were spectrally close. These results demonstrate the feasibility of using the MMN to measure spatial stream segregation, especially in populations for whom task-based behavioral experiments cannot be undertaken.
Spatial influences on change detection within complex auditory scenes
Authors: Dickerson Kelly , Gaston Jeremy , Scharine Angelique
Published: May 2014

Change deafness is the auditory analog to change blindness. Both phenomena represent a tendency to miss large changes in the environment, suggesting that sensory experiences are not verbatim and may details crucial for detection and identification. Spatial separation facilitates change detection in vision, but its role in auditory change detection is unclear. In this study, we examined the impact of spatial separation on the detection of appearing and or disappearing sound sources in an auditory scene. Participants listened to a brief auditory scene (1000 ms) comprised of four sources followed by a scene where a sound source was added or subtracted from the scene or where no change occurred. There were two listening conditions, where the sound sources were each distributed across a loudspeaker array, or the sound sources were all played from a single loudspeaker. Results indicate that listeners were better able to detect appearing than disappearing sounds, and fewer errors were made when sound sources were spatially separated. These results are consistent with an attention-based explanation of change detection failures. Further, the beneficial effect of spatial separation suggests that change blindness and deafness may share a common mechanism.
Spatial attention in an auditory dual task
Authors: Iyer Nandini , Thompson Eric R. , Romigh Griffin D. , Baldwin Carryl L. , Simpson Brian D.
Published: May 2014

Research on divided auditory attention has focused on the ability of listeners to report keywords from two spatially separated simultaneous talkers (Best et al., 2006); however, the information that listeners extract from each talker is the same (i.e., keyword identification). In realistic listening environments, there is often a competing demand for auditory attention; listeners might be required to monitor critical auditory events while also responding to an ongoing auditory signal. It is not clear how spatial separation affects performance in auditory dual-tasks under varying levels of task difficulty. Listeners identified an ongoing stream of color/number keywords originating at 0° azimuth (primary task), while detecting the presence of a critical call sign originating from locations ranging from −45° to + 45° (secondary task). The difficulty of the primary task was varied by introducing noise or by requiring stimuli identification in an auditory one- or two-back memory recall task. The difficulty of the secondary task was varied by increasing the set-size of critical call signs that listeners had to monitor and by changing the SNRs. Preliminary results indicate that a listener's ability to detect the presence of a critical call sign increased as its spatial location moved further away from 0° azimuth and performance was modulated bythe difficulty of the primary task. The result has important implications for spatial attention as a function of task difficulty in multitalker environments.
Rapid binaural processing for source segregation and lateralization
Authors: Reed Darrin K. , Josupeit Angela , van de Par Steven
Published: May 2014

For realistic listening conditions, interaural cues will fluctuate due to the presence of multiple active sources. If it is assumed that the binaural system is sluggish, then the perceived location of the sound input would be an average of the varying interaural cues. If, however, the binaural system is fast enough to assess the rapidly changing interaural differences, then it could be possible for the binaural system to properly identify the spatial position of a target source. Using a continuous, broadband noise stimulus that contained periodically alternating interaural time differences (ITD) and, notably, no monaural cues, we investigated the binaural system's ability to lateralize brief durations of the target ITD. Results show that listeners can lateralize targets for durations of 3–6 ms indicating that the binaural system allows for a segregation and lateralization of the target and interfering noise streams. Furthermore, results indicate that the binaural system mediates the buildup of a modulated stream. A second experiment investigating whether the salience of the target ITD in the aforementioned stimulus depends on the temporal position of the target within the phase of an amplitude modulated envelope revealed that this was not the case.
Binaural masking release: An increase in workload capacity
Authors: Lentz Jennifer , Townsend James
Published: May 2014

The following study applied reaction time analyses of workload capacity to tone-in-noise detection for monaural (NmSm), diotic (tone and noise identical at each ears; NoSo), and dichotic (tone is anti-phase but noise is not; NoSTT) conditions. Reaction times allow comparisons between these conditions at the same signal-to-noise ratios (something which cannot often be done using threshold and percent correct) and can also expose dynamic contributions to the release from masking provided by binaural interactions. Here, we apply a reaction-time based capacity coefficient, which provides an index of workload efficiency. We demonstrate that the release from masking generated by the addition of an identical stimulus to one ear (NmSm vs. NoSo) is unlimited capacity (efficiency ≈1), consistent with an independent parallel-channel model. However, the release from masking generated by the anti-phasic tone (NoSo vs. NoSTT) leads to a significant increase in workload capacity (increased efficiency)—most specifically at lower signal-to-noise ratios. These experimental results provide further evidence that configural processing plays a critical role in binaural masking release, and that these mechanisms operate more strongly when the signal stimulus is difficult to detect.
Binaural interference with dynamic interaural cues
Authors: Bibee Jacqueline M. , Stecker G. Christopher
Published: May 2014

Sensitivity to interaural time and level difference (ITD and ILD) in high-frequency amplitude-modulated sound is reduced by simultaneous presented low-frequency “interferers.” Often, the magnitude of this “binaural interference” is limited by the salience of the target cue. This study addressed the hypothesis of reduced interference for salient cues by restricting target cues to sound onset (high salience; condition “R0”) or sound offset (low salience for ITD, high salience for ILD; condition “0R”). In control condition “RR,” cues remained constant over duration. Targets were trains of 16 Gabor clicks (4 kHz carrier frequency, 2 ms interclick interval). In baseline conditions, targets were presented in isolation; in interference conditions, targets were gated simultaneously with a diotic 500 Hz tone. ITD or ILD detection thresholds were measured adaptively. Results demonstrated significant binaural interference across conditions, despite the use of pulsatile modulators and regardless of the presence or absence of onset cues. Ceiling effects resulted in unmeasurably high ITD (but not ILD) thresholds in some conditions. Consistent with the low salience of envelope ITD near sound offset, this occurred for a majority of subjects when interferers were present but onset cues were not. Work supported by R01-DC011548.]
Temporal weighting of interaural time differences in low frequency noise presented at low signal-to-noise ratio
Authors: Diedesch Anna C. , Stecker G. Christopher
Published: May 2014

Discrimination of interaural time difference (ITD) improves with increasing duration of a target stimulus, but more slowly than expected if ITD sensitivity was temporally uniform over the sound duration. Houtgast and Plomp [JASA 44, 807–812 (1968)] thus argued for nonuniformal temporal weighting of ITD, in which sound onsets dominate listeners' ITD judgments. That theory is well supported by recent work. Additional data reported by Houtgast and Plomp suggest more uniform weighting in the presence of masking noise at 5 dB signal-to-noise ratio (SNR). The current study measured ITD thresholds for 500 Hz octave-band noise targets with ITD fixed over duration (condition “RR”) or changing linearly from zero to peak value (condition “0R”) or vice versa ( “R0”). Targets were presented in the presence or absence of a continuous 500Hz octave-band masker (5dB SNR). Comparison data were obtained using 500 Hz pure-tone targets across identical ITD and masker configurations (Diedesch and Stecker, 2014, Assoc. Res. Otolaryngol.). ITD detection with pure-tone targets did not appear to benefit (in terms of threshold-vs-duration slopes) from masking noise as in Houtgast and Plomp (1968). Other stimulus conditions that more closely replicate the conditions of that study (i.e., noise targets) are discussed. [Work supported by NIH R01 DC011548.]
Murray Strasberg's contributions to the Navy's ship silencing programs
Authors: Feit David
Published: May 2014

Murray's long career with the U.S. Navy, extended over seven decades 1942–2012, and began when he joined the David Taylor Model Basin (DTMB), now the Carderock Division of the Naval Surface Warfare Center), in 1942. Soon after joining DTMB he was assigned to making cavitation noise measurements on World War II submarines or with model propellers in water tunnels. This lead to his long standing interest in cavitation and bubble noise, matters to be discussed by others in this session. I will discuss his work in structural acoustics, which grew out of his involvement with a propeller related signature source and ultimately proved to be one of his most significant contributions to the Navy's submarine silencing efforts.
Hydrodynamic noise—Murray Strasberg's legacy
Authors: Blake William
Published: May 2014

The decade of the 1950s provided us with the beginnings of sub-disciplines of acoustics that we now call aeroacoustics and hydroacoustics. In the beginning, the attention was placed on mechanisms relevant to the aeronautical engineering and the early rocket and space vehicle communities. Accordingly, much published work at the time dealt with jet noise and structural fatigue resulting from that noise and from turbulent boundary layer excitation. In 1956, Murray Strasberg and Hugh Fitzpatrick published a seminal paper, “Hydrodynamic Sources of Sound”, 1st Hydrodynamics Symposium. This paper put the aerodynamic noise theory of Lighthill (1952) in the context of Navy application and defined relevant source types. A. Prosperetti will discuss Murray's legacy regarding bubble noise and cavitation discussed in that paper. I will discuss the other interest of Murray: i.e., flow induced vibration and sound. Although he published little on this subject the impact that he had on others who did was important. Accordingly, Murray had continuing impact on the developing knowledgebase of flow-induced sound and vibration, and we will use the area of TBL noise as an example of how concepts in flow noise and vibration have evolved under Murray's career span.
Murray Strasberg and bubble acoustics
Authors: Prosperetti Andrea , Prosperetti Andrea
Published: May 2014

Murray Strasberg made seminal contributions to the nucleation and acoustics of bubbles. Half a century after publication, these papers still receive a sizable number of citations every year. The talk will review this work, comment on its impact, and put Strasberg's classical results in a modern perspective.
Low-frequency propeller forces and sound—Murray Strasberg's legacy
Authors: Anderson Jason
Published: May 2014

In the early 1960s, Murray Strasberg, after having already made significant contributions to the field of hydroacoustics in the areas of propeller cavitation noise and general hydrodynamic sources of sound, turned his attention toward low-frequency forces that are generated by propellers, which ingest non-uniform flow. Dr. Strasberg developed an elegantly simplistic approach to estimate the propeller unsteady thrust by actually measuring the sound pressure radiation from a prototype propeller installed in a wind tunnel test section. Murray's approach required that the propeller be acoustically compact, thereby allowing the propeller to be treated as a single dipole sound source. This approach offered by Murray, for which a U.S. patent was awarded in 1982, served as a simpler alternative to the more traditional and complicated approach of force dynamometry. Dr. Strasberg focused his efforts on measuring propeller thrust at the blade passage frequency tonals, but he did, however, encourage Maurice Sevik to perform his seminal propeller turbulence ingestion thrust research in the 1960s and 1970s, which truly ushered in the modern era of propeller turbulence ingestion research that continues today. In this presentation, we will describe Murray Strasberg's novel propeller unsteady thrust measurement approach, and we will discuss how researchers over the years have built upon Murray's foundational concept.