bluuebunny/crossref_metadata_2025 huggingface dataset:
A binaural localization model that resolves front-back confusions through head movements.
Authors: Braasch Jonas , Strong John T. , Xiang Ning
Published: March 2010

It is well known that head movements are instrumental in resolving front/back confusions in human sound localization. A mechanism for a binaural model is proposed here to extent current cross-correlation models to compensate for head movements. The algorithm tracks sound sources in the head-related coordinate system (HRCS) as well as in the room-related coordinate system (RRCS). It is also aware of the current head position within the room. The sounds are positioned in space using an HRTF catalog at 1 deg azimuthal resolution. The position of the sound source is determined through the inter-aural cross-correlation (IACC) functions across several auditory bands, which are mapped to functions of azimuth and superposed. The maxima of the cross-correlation functions determine the position of the sound source, but unfortunately, usually two peaks occur—one at or near the correct location and the second one at the front/back reversed position. When the model is programed to virtually turn its head, the degree-based cross-correlation functions are shifted with current head angle to match the RRCS. During this procedure, the IACC peak for the correct hemisphere will prevail if integrated over time for the duration of the head movement, whereas the front/back reversed peak will average out.
Modeling the precedence effect for multiple echoes.
Authors: Goupell Matthew J. , Litovsky Ruth Y.
Published: March 2010

A typical and controlled way to study the precedence effect has been to use two pairs of binaural click stimuli with different lead-lag delays. For lead-lag delays between 1 and 5 ms, interaural differences in the lead click pair are more easily discriminated than those in the lag click pair. This work attempts to move from the classic, but unrealistic, two-source paradigm to a more realistic situation, much like real rooms in which multiple echoes occur. Using a three-source paradigm, listeners were presented three click pairs (lead, lag1, and lag2) via headphones. Discrimination of directional changes in each of the three click pairs was measured with a 2AFC task for delays between 0 and 130 ms. Results show that due to interactions amongst the three sources “echo thresholds” were affected in a non-monotonic way. Temporal order effects were observed for long delays, which led to poorer lead discrimination, and better lag2 discrimination. Summing localization was observed for short delays between lead and lag1, and lag1 and lag2. A simple weighting model [Shinn-Cunningham et al., J. Acoust. Soc. Am. 93, 2923–2932 (1993)] was adapted to include this multiple source data and the complex relationships between the three sources. [Work supported by NIH-NIDCD R01 DC003083—R.Y. L.]
Tuning of head-related transfer functions using principal component analysis.
Authors: Fink Kimberly J. , Ray Laura R.
Published: March 2010

Modeling head related impulse responses (HRIRs) to determine head-related transfer functions (HRTFs) can be used to create a virtual auditory display through head phones. However, non-individualized HRTFs can create errors in sound localization and perception of the source as coming from inside vs outside of the head. We present a method, based on model-order reduction and principal component analysis, to “tune” generalized HRTFs derived from the CIPIC database of HRIRs in order to individualize an HRTF. The impulse response for each individual in the CIPIC database is modeled at given azimuth locations on the horizontal plane. Model order reduction is used to eliminate poles and zeros of the identified HRTF at high frequencies, while preserving the frequency response below ∼8000 Hz. Principal component analysis is then performed on the reduced-order models in order to reduce the dimensionality of the dataset and identify a subset of weighting variables that are adjusted during HRTF customization. The sensitivity of weights on the frequency response is also studied in order to correlate weights with HRTF features. A prototype auditory display has been developed that allows a user to tune HRTFs in real-time, while listening to a 44.1-kHz source presented from a chosen azimuth.
Reverberation disrupts spatial selective auditory attention.
Authors: Ruggles Dorea R. , Shinn-Cunningham Barbara G.
Published: March 2010

When there are multiple, competing speech streams, listeners can selectively attend to a desired target using spatial cues like interaural time differences (ITDs). However, reverberation smears fine temporal information needed to encode ITDs. Reverberation may therefore interfere with the ability to selectively attend to a target from a particular direction. Subjects were asked to report a stream of digits simulated to be directly in front of them in the presence of two masker streams symmetrically positioned at 15 deg left and right. Because the maskers were statistically identical to the target (except in direction), listeners had to focus spatial attention on the target while ignoring the masker streams. Three levels of reverberation were simulated using a rectangular room model to measure the influence of reverberation on performance. Initial results showed that spatial selective attention degraded as reverberation increased. However, overall performance varied dramatically from listener to listener in ways that were not predicted by age or memory span. The current study explores whether individual differences are predicted by performance on two discrimination tasks that rely on signal fine temporal structure: frequency modulation (a monaural task) and ITD (a binaural task). [NIDCD, ONR, and NSF provided funding to support this work.]
The effects of intervening interference on working memory for sound location.
Authors: Grossmann Aurora , Ries Dennis , Hamilton Traci
Published: March 2010

Inter-aural phase differences were used to study working memory for perceived auditory position quantified as a change in the difference limen (DL) in equivalent auditory angle across 300-, 5000-, and 15 000-ms retention intervals. Data were obtained for the medium and long intervals both in the presence and absence of intervening tones. Intervening stimuli within the medium and long inter-comparison intervals produced a significant increase in the DLs compared those obtained in the corresponding quiet conditions. The DL for the 300-ms interval was roughly equivalent to that obtained for the medium interval without intervening tones while that obtained for 15 000-ms interval was significantly greater than that obtained for either of the shorter intervals. The results suggest that the temporal decay of information within AWM of a listerner regarding the location of a sound within their environment is so gradual that it can be maintained in trace memory for tens of seconds in the absence of intervening acoustic signals. Conversely, the presence of interpolated sounds within the retention interval may facilitate the use of context memory, resulting in a less detailed, but relevant representation of the location that is resistant to further degradation.
Intrinsic damping, relaxation processes, and internal friction in vibrating systems.
Authors: Pierce Allan D.
Published: March 2010

Vibrations lose energy because of (1) coupling of the system to other systems or to the environment or of (2) intrinsic damping within the system itself. The present paper attempts to survey the current state of understanding for the principal mechanisms of the latter type with explicit physics (rather than purely phenomenological considerations), as simply as practical. Some mechanisms are evidenced in the attenuation of waves in unbounded homogeneous media, others are caused by the presence of boundaries. Some explicitly require quantum-mechanical concepts for their explanation, others can be explained in terms of classical mechanics and thermodynamics. Specific mechanisms that are to be discussed include those associated with thermal conductivity, grain and domain boundary effects, interstitial atom diffusion, relaxation by diffusion, inter-grain diffusion, micro-eddy current losses, hysteresis losses, thermoelastic internal friction, thermal damping associated with transverse vibrations of thin bodies, phonon-phonon interactions, phonon-electron interactions, internal fluids, and dislocations. The concept of relaxation often provides a convenient unified description. Rather than use the local averaged particle displacement as a sole description of the local vibrations, one considers additional local variables, loosely referred to as hidden variables. Each such variable, when disturbed, relaxes to its equilibrium value with a characteristic relaxation time.
Optimization of local damping treatments for plate vibrations.
Authors: McDaniel J. Gregory
Published: March 2010

This work considers passive damping treatments that dynamically interact with plates over areas that are much smaller than a flexural wavelength. Each treatment is modeled as a frequency-dependent admittance presented to the plate at a point. The frequency-dependence is required to satisfy the causality and minimum phase conditions, which are implicitly enforced via a specialized Fourier series in frequency. The Fourier coefficients, as well as the positions of the attachments, are regarded as optimization parameters to be varied so as to globally decrease plate vibrations over a frequency band of interest. Various cost functions are considered, such as the sum of modal loss factors over the band as well as acoustic radiation efficiencies. Examples involving a simply supported plate excited by a point force illustrate the approach. [Work supported by ONR under Grant No. N000140810531.]
Radiation damping and scattering reduction by transformation acoustics.
Authors: Norris Andrew
Published: March 2010

The idea in transformation acoustics is to map one region into another so that the new region has the same acoustic appearance to observers as the original. It is analogous to transformation optics and is closely related to devices for cloaking, but it is not restricted to cloaking. This talk will explore the implications of transformation acoustics for radiation damping and scattering. Mechanisms for realizing transformed regions, which we call acoustic metafluids, will be described. The objective in these materials is to bend the waves so that energy can be steered around a given region, and thereby reduce the scattering strength. But it is not as obvious how these materials influence the radiation from an active source inside. In this talk we will discuss the implications of transformation acoustics on radiation using fundamental concepts, including acoustical reciprocity, mechanical impedance, and energy flux.
Transmission loss of membrane-type locally resonant acoustic materials.
Authors: Naify Christina , Chang Chia-Ming , Carter Bill , McKnight Geoff , Nutt Steve
Published: March 2010

Membrane-type acoustic metamaterials were fabricated, characterized, and analyzed. Thin plates which obey the acoustic mass law have low transmission loss at low frequencies. Acoustic metamaterials with negative dynamic mass density have been shown to demonstrate a significant (ten times) increase in transmission loss (TL) over mass law predictions for a narrow band (100 Hz) at low frequencies (100–1000 Hz). The peak TL frequency can be tuned to specific values by varying the membrane and mass properties. In this work, transmission loss magnitude as a function of frequency was measured for variations in the mass magnitude, mass placement on the membrane, membrane size, and membrane thickness using an impedance tube setup. The dynamic properties of membranes constructed from different materials and thicknesses were measured and compared to the results of coupled field acoustic-structural FEA modeling to understand the role of tension and element quality factor. In addition, the behavior and limitations of stacking multiple membranes in series to increase the reflection bandwidth were explored.
Rapid step response with limited ringing and light damping.
Authors: Vignola Joseph , Judge John
Published: March 2010

The time domain step response of an underdamped simple harmonic oscillator can be characterized as having two parts. The first is a transition from the initial position where the structure is accelerated toward a target position by a step force that introduces energy to the system. The second is a ringdown process, involving decaying oscillations about the target position as energy is removed from the structure. This study reports how an array of substantially smaller subordinate oscillators attached to the primary structure can dramatically reduce the time constant of the ringdown (the settling time) without slowing the first phase (rise time) in the way added classical damping does. In addition to having a more rapid initial response, a lightly damped oscillator with such an array of attachments requires less energy to change states than a more heavily damped structure. The approach is based on the concept of apparent damping, where vibration energy is transferred into and trapped by the set of attachments. Numerical results show that the distribution of the individual masses, isolated natural frequencies, and quality factors Q of the attachments, referred to as a subordinate oscillator array, can be tailored to achieve the rapid step response.
Application of time windowing to spatial maps of damping.
Authors: Öztürk Hande , McDaniel J. Gregory
Published: March 2010

Some of the most challenging vibration control problems involve the selection and placement of frequency-dependent damping devices, such as multilayered viscoelastic materials. In complex structures involving the simultaneous use of several passive damping devices, it is difficult to determine the effectiveness of each device directly from measurements. This question motivates the present analysis, which seeks to quantify the power being dissipated by the structure at selected locations for a given force distribution. The analysis begins with an expression for power flow to the structure from a specified force distribution. This expression involves the real part of the admittance matrix looking into the structure at a set of measurement points. By expanding this matrix as a sum over damping elements that mechanically connect measurement points, one can spatially map the power flow into the structure. While thermodynamics requires that this power flow to the structure be equal to the power dissipated by the structure, it does not require equality of the spatial distributions. In order to understand the spatial distribution of power dissipation, time windowing of the impulse responses is introduced. Examples are developed to explore the effects of the time window. [Work supported by ONR under Grant No. N000140810531.]
What do comparisons between younger and older adult listeners tell us about speech processing?
Authors: Pichora-Fuller Margaret K.
Published: March 2010

The perception of speech, the recognition of words, and the understanding of spoken language involve the dynamic and interactive processing of cues provided by the incoming signal and information stored in memory. Even when accuracy is high, the relative contributions of bottom-up and top-down processes may explain variations in the speed and effort required when listening to speech. Listening is fast when the quality of the incoming signal is optimal, but it is slowed as signal quality is reduced. Likewise, listening can be speeded when expectations constrain the likely alternatives or when priming implicitly facilitates the recognition of the signal, whereas it can be slowed if the context is incongruent with the signal or if context is used to resolve ambiguities or repair misperceptions in a compensatory fashion. Within-subjects comparisons on off-line and on-line measures in different listening conditions, including simulations of auditory aging and hearing loss, are used to investigate how listening effort varies and how listening is speeded or slowed depending on signal-driven and knowledge-driven factors. Comparisons between younger and older participants are used to evaluate how long-standing reductions in auditory temporal processing and compensatory changes in brain organization may alter how signal-driven and knowledge-driven processes interact.
Interpreting speech in context.
Authors: Pitt Mark
Published: March 2010

One of the challenges in understanding how humans recognize spoken language is to reconcile the robustness of verbal communication with the many forms of ambiguity and variability in the speech signal. How much of the discrepancy is due to our incomplete understanding of the acoustics of speech (i.e., what is the critical information) versus the recruitment of mental processes (e.g., memory) to aid recognition? My approach to these explanations has been to study the processing of words that have been degraded in controlled ways (e.g., digital manipulation) and by using conversation-style speech that contains naturally produced ambiguities. Recognition is measured in isolation and in sentences using a variety of tasks whose purpose is to measure the source, magnitude, and time course of ambiguity resolution. I will present an overview of this work in the context of a few experimental settings, highlighting methodological issues along the way. Together, the findings suggest that word recognition is a highly fluid process that depends on the rapid integration of multiple sources of information.
Acoustical design of special purpose rooms in schools: Cafeterias and cafetoriums.
Authors: Siebein Gary W. , Paek Hyun , Jones Chris P. , Skelton Reece
Published: March 2010

Design strategies for cafeterias and cafetoriums in elementary, middle, and high schools based on an impulse response-based theory are presented through a series of case studies of existing, renovated, and designed rooms. The strategies include use of sound absorbing materials to control noise build-up for dining areas; integrated design of stage, canopy, shells (where used), and sound reinforcement systems to project sounds to the audience in a multi-use situation; controlling room volume and absorption to allow early sound reflections for clear hearing; providing for clear verbal communication between teachers and students with the audience; and limiting background and intruding noise levels. The impulse response-based measures are reduced to a series of architectural systems that can be implemented using alternate construction systems to meet budget requirements. Standard design concept sketches communicate the intent of the acoustical design to architects, school board members, design builders, and music faculty.
A new sound system in a reverberant high school gymnasium.
Authors: Kanter Shane J. , Hoeman Stephanie L. , Coffeen Robert C.
Published: March 2010

A new and well designed sound system was recently installed in a very reverberant high school gymnasium. While the new sound system performs much better than the previous system, would its performance be significantly better if the gymnasium reverberation time and undesirable sound reflections were properly controlled? This situation is investigated with binaural audio recordings of the new sound system with the existing room acoustics and by computer modeling and computer auralization with existing acoustical conditions and with improved room acoustics.
Design constraints and opportunites of two similar-function auditoria.
Authors: Lee Robert , Miller Andrew
Published: March 2010

Two high school auditoria are examined, one new construction and one renovation. The multi-purpose uses, size, and scope of both rooms are very similar, but they demanded very different design approaches due to the varying constraints and opportunities presented by the site, the owner, the existing building, and other factors.
Case studies: Auditorium, gymnasium, and gymnatorium.
Authors: Woolworth David S.
Published: March 2010

Three case studies of multipurpose rooms in schools with restricted budget. Areas covered include considerations with regard to function, re-use of materials, acoustic treatments fit under the school board’s scope, hearing impaired provisions, noise issues, and electroacoustic design.
Echolocation of moving objects by using the frequency modulated sound.
Authors: Matsuo Ikuo
Published: March 2010

Using the echolocation, bats can capture moving objects in real three-dimensional space. Bats emit the frequency modulation sound and can identify objects with an accuracy of less than a millimeter. To determine delay times of multiple objects requires estimating the sequence of delay separations by extracting temporal changes in the interference pattern of the echoes. The models have been previously proposed to determine delay times of multiple objects by using the frequency modulation sound. In order to extract the temporal changes, Gaussian chirplets with a carrier frequency compatible with emission sweep rates were used and each delay time was estimated by using the temporal changes. It was examined that this model could estimate each delay time within the accuracy less than 1 mm in the case of measuring echoes from fixed objects. In this paper, the echoes were measured from moving objects, and it was examined that this model could estimate each delay times of these objects.
Auditory brainstem response in the lesser scaup (Aythya affinis), a species of diving duck.
Authors: Therrien Sara C. , Carr Catherine E. , Brittan-Powell Elizabeth F. , Wells-Berlin Alicia M.
Published: March 2010

The auditory brainstem response (ABR) is an effective approach to describing auditory sensitivity in a variety of animals. In this investigation, we used the ABR to estimate the auditory sensitivity of a species of diving duck, the lesser scaup (Aythya affinis). The typical lesser scaup ABR waveform showed two to three prominent peaks that occurred within the first 5 ms after onset of the stimulus. Peak amplitude increased and peak latency decreased with increasing stimulus sound pressure level (SPL). Threshold was defined as 2.5 dB below the lowest SPL that evoked a visual response (visual detection method). The best range of hearing for this species was from 500 to 5000 Hz, with sensitivity peaking between 1500 and 3000 Hz. Both the waveform morphology and response characteristics of the peaks to changing stimulus intensity are similar to those found in other avian species, such as screech owls (Megascops asio) and budgerigars (Melopsittacus undulatus).
Texture discrimination by echolocation in the big brown bat.
Authors: Falk Ben , Aytekin Murat , Moss Cynthia, F.
Published: March 2010

Echolocating bats emit high-frequency vocalizations and listen to the returning echoes to sense their environment. Echolocation transforms the physical environment into acoustic energy which bats use for navigation and prey capture. This study examined the capabilities of the big brown bat, Eptesicus fuscus, to identify and discriminate textured objects. The bat was trained to discriminate a smooth object from a textured object, both spherical, ∼ 15 mm diameter, and tethered to the ceiling in a large flight room. The bat was free to fly and investigate the objects before making its decision (signaled by tapping one of the objects in flight − correct=smooth). The bat’s discrimination performance was measured with a series of textured objects. Quantification of texture was made through acoustic recordings of the objects. High-speed video recordings allowed a reconstruction of the bat’s three-dimensional flight path, full bandwidth ultrasound-sensitive microphones allowed recordings of the bat’s sonar emissions, and an array of microphones positioned around the flight room allowed a reconstruction of the bat’s sonar beam pattern. The relationship between the bat’s performance and the acoustic recordings of the stimuli was examined. How the bat’s motor behaviors contribute to its discrimination performance was investigated. [Work supported by NSF(REU), NIMH(R01MH056366.]
Repertoire and possible functions of social calls in foraging big brown bats (Eptesicus fuscus).
Authors: Wright Genevieve S. , Chiu Chen , Moss Cynthia F.
Published: March 2010

While the echolocation calls of big brown bats (Eptesicus fuscus) have been studied extensively, this species’ communicative vocalizations have received little attention. Calls were recorded from pairs of bats flying in a laboratory flight room in a foraging context. Pairs consisted of naive bats flown with individuals that were either experienced about how to take a tethered insect or naive or of two experienced bats flying together. This situation elicited a variety of vocalizations with properties different from typical E. fuscus echolocation calls. Seven different call shapes that occurred only when two bats were present were identified and categorized. These included chirp-like calls, rising frequency calls, calls that were longer than 20 ms in duration, and series of ultrasonic, chirp-like calls (or “songs”) produced only by male bats and displaying individual variation. Some call types were only recorded when a juvenile was present or very rarely in adult-only pairs. Using high-speed video data collected in synchrony with the audio recordings, the contexts and possible functions of various calls are evaluated. The rate at which different call types were recorded with regard to bats’ knowledge of the foraging task and the age and sex of bats flown together is also considered.
Behavioral sensitivity to interaural difference cues in the budgerigar (Melopsittacus undulatus).
Authors: Welch Thomas E. , Garcia Kristen , Dent Micheal L.
Published: March 2010

Interaural time and level differences cues (ITDs and ILDs) allow organisms to localize sounds and detect and discriminate signals in noise. Behavioral sensitivity to these important cues has only been studied in humans and a few species of animals. Although the abilities of budgerigars to localize, detect, and discriminate a variety of sounds in quiet or noisy conditions are well known, this is the first study to equip birds with headphones so that their sensitivity to ITDs and ILDs can be measured using lateralization procedures. In one experiment, thresholds are measured behaviorally in budgerigars using pure tones (0.5–8 kHz) and broad-band noise as stimuli in a two-alternative (left-right) identification task. In another experiment, sensitivity to changes in ITDs and ILDs of binaural sounds within a repeating background (discrimination task) is measured using the same stimuli as the first experiment. Budgerigars appear to be less sensitive than humans to both ITDs and ILDs, but similar to cats and monkeys. Overall, these lateralization results are generally consistent with the free-field localization abilities of these birds, but their relatively acute sensitivity to interaural difference cues adds support to the idea that budgerigars may be using their connected interaural pathways to enhance directional hearing.
The effects of frequency content on auditory streaming in budgerigars and zebra finches.
Authors: Garcia Kristen A. , Rajaram Siddharth , Sen Kamal , Shinn-Cunningham Barbara G. , Dent Micheal L.
Published: March 2010

Auditory streaming is a phenomenon that has been documented in a wide variety of animal species. Recently, space, intensity, time, and spectral composition were all found to be important factors for auditory streaming of birdsong by budgerigars and zebra finches, although the cues varied in importance. Those experiments were extended here to further examine the role of frequency characteristics on the auditory streaming of birdsong. The birds were initially trained using operant conditioning procedures to differentially peck keys in response to either a synthetic zebra finch song consisting of five syllables (whole song) or to the same song with the fourth syllable omitted (broken song). Correct responses were reinforced with millet, and incorrect responses were punished with a lights-off timeout period. Once the birds reached high-performance levels with the training stimuli, probe trials were inserted on a small portion of all trials. The probe stimuli contained either a white noise burst in the missing syllable’s location or narrowband pieces of the original fourth syllable. Results show that the different cues are differentially effective in eliciting streaming of birdsong by zebra finches and budgerigars, similar to the previous experiments and results from human speech experiments.
Vocal behavior of North Atlantic humpback whales during reunion events on Stellwagen Bank.
Authors: Palmer Kaitlin , Parks Susan E. , Wiley David , Weinrich Mason , Tackaberry Jennifer , Bocconcelli Alessandro , Friedlaender Ari
Published: March 2010

Humpback whales on their feeding grounds are typically found in small, ephemeral groups which have been hypothesized to form and separate to maximize foraging efficiency, but little is known about the functional mechanisms by which these groups change their composition. In this study, we test the hypothesis that specific vocalization types are associated with events where two or more individual humpback whales join to form a cohesive group on their summer feeding grounds. In the summer of 2008, 11 Dtags (a combined acoustic and movement recording tag) were attached to individual humpback whales on their feeding grounds in the Stellwagen Bank National Marine Sanctuary. Behavioral observations were collected from tagged animals at the surface and the timing of join events were recorded. Calls from the tagged whale and nearby associates were identified and analyzed to test for call rate changes between 10 min periods around joining events and 10 min control periods. Additional analyses included call type usage during joining events. Our results indicate a trend toward increased call rates during join events when compared to randomly selected control periods, with evidence of differential usage of specific call types during join events.
Measurement of Copepodid and Nauplii populations in the Golfo della Biodola using inverse acoustic methods.
Authors: Fornshell John
Published: March 2010

Acoustic observations and simultaneous collection of plankton were made in the Gulf of Biodola on the northern coast of the Island of Elba, Italy. The fieldwork was conducted on the 10th and 11th of October 2009 on the R/V LEONARDO. The acoustic measurements were made using the autonomous underwater vehicle, MUSCLE, at a working frequency of 300 kHz. Plankton samples were also collected simultaneously with a 1/4 m Nansen net with a 20 mm mesh size. The acoustic data were processed by scientists at the NATO Undersea Research Center and provided to the author. The waters of the southern Ligurian sea on this coast are exceptionally clear with very low plankton population densities. The plankton were sorted, identified, and enumerated at the National Museum of Natural History, Smithsonian Institution. It is assumed in this study that the volume back-scatter can be attributed to the plankton in the water column. The numbers in the net samples are compared with the values from the inverse acoustic methods.
Discovery of sound in the sea: An on-line resource.
Authors: Vigness-Raposa Kathleen J. , Scowcroft Gail , Knowlton Christopher , Morin Holly
Published: March 2010

The scientific community and the public have become increasingly aware of, and concerned about, underwater sound. There is increasing interest in learning about sources and uses of sound, and potential effects of sound on the environment. Underlying this interest, however, is a need to provide scientific information at a level appropriate for the general public and for educational and media professionals. The discovery of sound in the sea website (http://www.dosits.org) provides scientific content introducing the physical science of underwater sound and how people and animals use sound to accomplish various tasks. It also includes three major resource sections. The Media Resources include a Facts & Myths quiz, Frequently Asked Questions, and PDF reprints of a tri-fold pamphlet and a 12-page educational brochure. The Teacher and Student Resources include structured tutorials and educational games. DOSITS recently launched a significantly redesigned site. The look and feel have been refreshed without losing functionality and content. The redesign includes an interactive front page, an interactive Audio Gallery, and a redesigned Scientist Gallery. DOSITS provides easy, efficient access to timely information on the science of underwater sound and the current state of knowledge of the effects of underwater sound on marine mammals and fishes.
Lake bottom forward scattering measurement and model/data comparison.
Authors: Wu Jinrong , Ma Li
Published: March 2010

The lake bottom scattering function depends, in general, on the grazing angles and the azimuthal angles of the incident and scattered energy. However, most measurements were for backscatter only. Little was understood about forward bottom scattering in shallow water. In order to address this issue, an experiment was conducted in Qiandao Lake using 16 element vertical array and 8 element horizontal array. The measurement result indicated that there was relatively strong scattering in the forward direction near the specularly reflected ray, while the scattering was much weaker and relatively isotropic away from the specular ray. The Ellis and Crowe’s three-dimensional scattering function was used to predict the forward scattered energy. Comparsion between model and measured data has shown that the model can explain the lake bottom scattering well, and the frequency dependence of bottom scattering function from 5 to 9 kHz can be neglected. [Work supported by the NSFC.]
Data-based speech synthesis: Progress and challenges.
Authors: Bunnell H. Timothy , Syrdal Ann K.
Published: March 2010

In contrast to knowledge-based techniques such as articulatory or rule-based formant synthesis, data-based approaches to speech synthesis derive synthetic voices from a corpus of recorded human speech. Current “unit selection” data-based systems can produce synthetic utterances that rival human speech in intelligibility and naturalness by concatenating units of various sizes derived from large searchable corpora of speech aligned with tags that capture a rich set of segmental and prosodic features assigned to phonemic or subphonemic units. Emerging data-based techniques use machine learning algorithms to derive parameters automatically for parametric speech synthesis. Whatever the approach, because the extensive corpus of speech data used to construct most modern data-based systems is obtained from an individual talker, the synthetic output of the system captures much of the vocal identity of that individual. This latter feature has opened up new areas of application, such as personalized synthetic voices and “voice banking” for patients who might lose the ability to speak. This talk will trace the development of current data-based approaches, describe applications of this synthesis technology, and discuss some of the major challenges driving current research efforts. [Some work supported by NIDCD Grant R42-DC006193.]
Hot topics in structural acoustics.
Authors: Capone Dean E. , Allen Matthew S.
Published: March 2010

In this paper, an overview of the many opportunities and new research focus areas that are hot topics within the structural acoustics community in the Society will be presented. The talk will discuss the topics within the general categories of computational, analytical, and experimental structural acoustics. In particular, numerical methods in structural acoustics are receiving considerable attention, and a variety of proposed new approaches to structural acoustic computational modeling will be reviewed.
Assessing attitudes toward military blast noise.
Authors: Nykaza Edward T. , Hodgdon Kathleen , Luz George , Krecker Peg
Published: March 2010

Existing impact assessment procedures for large weapon noise or blast noise do not fully meet the military’s noise management needs. Military noise impacts currently are assessed in terms of the response metric annoyance as predicted by a long-term average noise level metric. This method has proven to be unsatisfactory for impulsive military noise. As a result, ERDC-CERL and SERDP have launched a series of field studies to enhance the understanding of human response to military blast noise. An overview of the four research protocols employed in this project will be presented, and the most recent findings from a qualitative personal interview study and a complaint and annoyance comparison study will be given. The preliminary results indicate that residents living near military installations adapt to the basic noise environment over time, notice unusually large noise events or events that produce house vibrations, and indicate that those who file complaints are significantly more annoyed on average than their neighbors who were exposed to a similar noise environment. All findings in this project thus far indicate that the number, timing, and level of discrete blast events are important for predicting the human response to blast noise.
Field experiment on vibration and acoustic responses of building to sonic booms using impulsive sound source.
Authors: Naka Yusuke , Doi Tetsuya , Kaku Jiro
Published: March 2010

Annoyance related to sonic boom is believed to be enhanced in indoor spaces by vibration of building walls, window rattles, room acoustic effects, and so forth. For investigating such vibration and acoustic effects of sonic booms in buildings, both laboratory and field experiments have been conducted. Although propagation of sonic booms in space and relative phenomena such as diffraction around a building can be reproduced in field experiments, it is sometimes not straightforward to generate sounds similar to sonic booms in open space. In this study, an easy-to-handle, portable device suitable for simulating sonic booms in field experiments is developed. A device developed by some of the authors to generate impulsive sound with fair level of infrasonic components by using compressed air is modified to simulate the negative overpressure of sonic booms. The improved device is used in a field experiment to investigate vibration and acoustic responses of a small house. Results of this preliminary experiment will be reported.
Rattle laboratory testing of windows exposed to sonic boom excitation.
Authors: Sizov Natalia V. , Hobbs Christopher M.
Published: March 2010

One of the major factors contributing to the annoyance indoor listeners experiencing sonic booms is window rattle. In earlier work the authors experimentally obtained a data set of responses of a large number of different window types installed in residential houses. Several of the windows studied were removed intact from tested houses and brought to a laboratory facility for further testing. They were affixed to a massive upright stand that simulated the house wall. These windows were acoustically excited using the same portable sonic boom simulator as in the in-situ tests. The results collected during the laboratory testing showed that rattle sources depend on window construction. Main rattle mechanisms were identified. Based on the knowledge gathered, a semi-empirical rattle model was developed defining the key parameters. Vibrational response of the window subjected to sonic boom excitation was modeled as a single degree of freedom system. The ratio between window element velocity and rattle-radiated sound pressure was obtained experimentally for the laboratory tested windows. The rattle-radiated sound level in the laboratory was compared with sound pressure levels received in front of house window exposed to typical and to low booms during NASA supersonic flight testing in 2007. [Work supported by NASA.]
Human response to sonic booms and rattle heard indoors.
Authors: Loubeau Alexandra , Klos Jacob , Rathsam Jonathan , Sullivan Brenda M. , Gavin Joseph R.
Published: March 2010

Human response to sonic booms heard indoors is affected by the generation of contact-induced rattle noise. The effect of sonic boom-induced rattle noise was studied in a series of psychoacoustics tests. In order to remove the effects of loudness, sounds were equalized to the same perceived level (PL) in each test. Stimuli were divided into three categories and presented in three different studies: isolated rattles at the same calculated PL, sonic booms combined with rattles at the same calculated PL, and sonic booms combined with rattles at three different PL. The sonic booms, both measured and synthesized, were filtered to simulate presentation inside structures with different transmission and reverberation properties. The rattle sounds due to sonic booms or mechanical loading were recorded in a residential home. Subjects listened to sounds over headphones and were asked to judge the level of annoyance of other factors, depending on the test. Annoyance to different rattles is shown to vary, and the combination of sonic booms and rattles can be more annoying than the sonic boom alone. These results show that the PL metric does not fully represent human annoyance to the selected indoor sonic boom and rattle sounds.
An examination of repeatability in physiological responses to simulated low amplitude sonic booms of various peak levels and rise times.
Authors: Marshall Andrew , Davies Patricia
Published: March 2010

Findings from recent low-level sonic boom studies have shown that people’s evaluations of startle could not be explained by loudness only and the startle evaluations were correlated strongly with evaluations of annoyance. A pilot study was conducted to examine how changes in physiological responses (skin conductance, pulse rate, and EMG) compared with subjective ratings startle. Analysis of this data was difficult because the intervals between stimuli were not long enough for some of the physiological measures to return to baseline before the next stimulus exposure. In addition, repeatability of responses was difficult to measure because of the complexity of the test which involved the subject doing several tasks while being exposed to the sounds. To examine what level of physiological response repeatability can be expected in these sonic boom experiments, another test was conducted in which subjects were exposed to simulated sonic booms. The interval required between boom exposures necessary to return to baseline was also examined. To examine the day-to-day repeatability of these measures, each subject completed several sessions on separate days. The variations in physiological responses within and between subjects will be described along with the trends observed related to signal characteristics.
Assessing sonic boom responses to changes in listening environment, signature type, and testing methodology.
Authors: Miller Denise M. , Sparrow Victor W.
Published: March 2010

The aim of this research was to investigate human response to low-amplitude sonic booms, specifically focusing on listening environment, character variation in sonic boom signatures, and subjective test methods. Two tests were conducted in which subjects rated annoyance of numerous low-amplitude sonic booms using magnitude estimation and categorical line scaling methods. One test utilized Gulfstream Aerospace Corporation’s Supersonic Acoustic Signature Simulator (SASSII), while the other was conducted in typical office and outdoor patio settings using a headphone playback system. The test stimuli consisted of indoor and outdoor recordings of low-amplitude sonic booms recorded by NASA researchers during flight tests at Edwards Air Force Base. The results include a comparison of subjective methods as well as the effect of listening environment on human annoyance of low-amplitude sonic booms. [Work sponsored by the NSF and the PARTNER Center of Excellence.]
Structural response to low-amplitude sonic booms.
Authors: Gavin Joseph , Klos Jacob , Loubeau Alexandra , Sullivan Brenda
Published: March 2010

Two highly instrumented homes have been ensonified by low-amplitude sonic booms. The resulting measurements have been analyzed (1) to gain insight to the dominant physical acoustics associated with sonic booms heard indoors and (2) to rank order the mechanisms needed for high-quality auralizations. The mechanisms turn out to be both clear and elegant. Diffraction loading on the exterior surface is as expected with an enhancement around on the incident side of the home and a strong shadow zone at higher non-dimensional frequencies. The resulting pressure loading induces modal vibration of the walls, ceiling, and windows; each of which show their first flexural modes at frequencies below 20 Hz. The walls themselves appear to break up into multi-layered wave bearing structures around 100 Hz, above which the nonlinear contact and sliding mechanisms take on a dominant role in the signature. These insights have been combined to motivate a low-dimensional tool for auralizing the complete audio bandwidth of booms heard indoors.
A method for including manner of contact in the synthesis of impact sounds for perceptual research.
Authors: Stoelinga Christophe N. J. , Lutfi Robert A.
Published: March 2010

Impact sounds synthesized according to a physical model have increasingly become the stimulus of choice in studies of sound source perception. Few studies, however, have incorporated manner of contact in their models because of the many parameters entailed in its description. Based on the work of Zener [Phys. Rev 669–673 (1941)], we show that the seven Hertzian parameters required to completely describe the contact can be reduced to just three: force of contact, duration of contact (tc) and a non-dimensional parameter (λ). Using only these parameters for the contact, a simplified method is presented to synthesize the impact sounds of simply supported plates. The results of the method are shown to be in good agreement with those of the more comprehensive method of Chaigne and Lambourg [J. Acoust. Soc. Am. 1422–1432 (2001)], the only such method to receive validation through acoustic measurement of plates. Psychometric functions obtained from listeners for the discrimination of tc and λ also show these parameters to be clearly discriminable over the range for which they would realistically vary. Potential advantages of using the simplified method over more comprehensive methods of sound synthesis in perceptual studies are discussed. [Research supported by NIDCD Grant No. 5R01DC006875-05.]
Acoustic analysis of perceptual sound categories.
Authors: Heller Laurie M. , Skerritt Benjamin
Published: March 2010

Acoustic analyses were conducted on several groups of sound events. The sound events were derived from a combination of physical analyses and perceptual data. The acoustic analyses utilized both low-level properties, such as spectral centroid, and higher-level properties. The higher-level properties were based on a combination of the physical source characteristics of basic classes of sound-generating events, statistical methods, and perceptual characteristics. A range of metrics are used to evaluate the success and generality of these acoustic properties, including classification performance and comparison to other results in the literature. (Work supported by NSF.)