bluuebunny/crossref_metadata_2025 huggingface dataset:
Speech perception based on spectral peaks versus spectral shape
Authors: Hillenbrand James M. , Houde Robert A.
Published: October 2013

Some spectral details are more intimately associated with the transmission of phonetic information than others, and a good deal of phonetic perception research has involved drawing inferences about the nature of the spectral representations that mediate phonetic recognition by conducting listening experiments using speech signals which are contrived in such a way as to retain only some characteristics of the speech signal, while purposely removing or distorting other spectral details. The present study was designed to address one aspect of this problem having to do with the relative contributions of spectral envelope peaks versus the detailed shape of the spectral envelope. The problem was addressed by asking listeners to identify nonsense syllables that were generated by two structurally identical source-filter synthesizers, one of which constructs the filter function based on the detailed spectral envelope shape, while the other uses a coarse estimate that is constructed entirely from the distribution of peaks in the envelope. Results suggest that nearly as much phonetic information is conveyed by the relatively coarse peaks-only representation method as by the method that preserves the fine details of the original envelope. However, there is a modest but reliable increase in the transmission of phonetic information when the detailed envelope shape is preserved.
The Boundary Characterization 2001 Experiment
Authors: Holland Charles , LePage Kevin , Harrison Chris , Hines Paul , Ellis Dale , Osler John , Hutt Dan , Gauss Roger , Nero Redwood , Preston John
Published: October 2013

The weakest link in performance prediction for naval systems operating in coastal regions is the environmental data that drive the models. In shallow water downward refracting environments, the seabed properties and morphology often are the controlling environmental factors. In the Boundary 2001 Experiment, seabed, surface, and biologic scattering, seabed reflection, propagation, reverberation, and ambient noise data were collected in order to develop and refine measurement techniques for key environmental model inputs. Both Rapid Environmental Assessment (REA) methods and high-resolution measurement techniques were employed from 0.1–10 kHz. Supporting oceanographic, geologic, and geophysical data were also collected. The experiment was conducted in May 2001 in two littoral regions: the New Jersey shelf and the Scotian Shelf. This paper provides an overview of the experiment objectives, hypotheses and conduct. [Research supported by NATO SACLANT Undersea Research Centre, ONR, and DRDC-A.]
Modeling of reverberation in the East China Sea
Authors: Yudichak T. W. , Knobles D. P. , Cable P. , Dorfman Y. , Zhang R. , Peng Z. , Li F. , Li Z. , Dahl P. H. , Miller J. H. , Potty G. R.
Published: October 2013

Reverberant time series recorded in the East China Sea component of the Asian Seas International Acoustics Experiment are analyzed with the aid of a model of acoustic scattering from inhomogeneities in the seabed. Wideband sources deployed by the IOA were used to produce the time series, which were recorded on a thirty-two element VLA also deployed by the IOA. The model employs perturbation theory with the framework of a normal mode approach to evaluate scattering by fluctuations in the sound speed and density in the sediment volume as well as of the roughness of the water–sediment interface. The relative importance of surface and volume scattering at low frequencies in shallow-water environments, such as the East China Sea experimental location, is considered. Also, by incorporating this model in an environmental inversion scheme, information about the distribution of inhomogeneities may be gained. [Work supported by ONR.]
Effects of bathymetric and oceanographic variations on short range high frequency acoustic propagation in shallow water
Authors: de Moustier Christian , Mogk Seth , Hock Melissa , D’Spain Gerald
Published: October 2013

Detailed bathymetry of shoaling regions at two shallow water sites of the San Clemente Offshore Range in Southern California is combined with oceanographic data, taken with CTD, XBT, and bottom moored ADCPs during the winter and summer conditions, to evaluate the effects of environmental variability on acoustic transmission loss and ambient noise measurements made at 16 discrete frequencies ranging from 3 kHz to 30 kHz over 10 km path lengths. Over such short ranges, bottom slopes and tidal effects have the strongest influence on acoustic propagation. [Work supported by the U.S. Naval Oceanographic Office.]
Sensitivity of broadband propagation and reverberation to oceanographic and bottom variability in shallow water wave guides
Authors: LePage Kevin D.
Published: October 2013

In a previous paper the author derived closed form expressions for the average intensity of broadband time series averaged over oceanographic variability in range independent wave guides [LePage, J. Comput. Acoust. 4 (2001)]. Here, equivalent expressions are derived for the expected value of reverberation intensity. Examples are computed which show that for time series, oceanographic variability most strongly affects the earliest arrivals, while bottom variability most strongly affects the late arrivals. For reverberation, the relative sensitivity to bottom and oceanographic variability were explored using the new model. [Work supported under the ONR capturing uncertainty DRI.]
The acoustic design of the Centro Nacional de las Artes in Mexico City
Authors: Cooper Rusell
Published: October 2013

In this paper the acoustic design of the separate buildings housing the school of music, school of drama, and school of dance that opened in 1996 will be described. Spaces that JHA designed included practice rooms, studios, rehearsal rooms, black box, and concert hall. Details of room acoustic treatments, sound isolation measures, and venturi air flow will be illustrated. An overview of the entire project will also include the 500 seat multipurpose theater (with variable absorption systems) and the Alla Magna. Differences between the American and Mexican styles of consulting, importing of materials, installation, and commissioning will also be discussed.
National Television of Chile—New headquarters building acoustic projects
Authors: Huaquin Mario
Published: October 2013

In the last 15 years TV stations in Chile have been incorporating in their facilities architectural acoustic and noise control approaches. This has been necessary as much for the technological advance, as for the necessity to achieve a better quality of sound that the listeners receive. In 1998, the National Television of Chile, with the sponsorship of the College of Architects of Chile, requested preliminary architectural designs in order to enlarge and to renovate its headquarters buildings in Santiago, Chile in stages. The Acoustic Project has been developed in an integral way, with three fundamental disciplines: noise and noise control; Machine rooms; vibrations and vibration control; Buildings, engines; architectural acoustics and acoustic comfort; TV studios and technical rooms. This presentation describes the Acoustic Project, phases I (1999), and II (2002), how it was possible to establish a common language with architects and engineers and the different specialties, to apply acoustic criteria and standards, the theoretical development and the projected acoustic solutions. (To be presented in Spanish.)
Acoustic simulations of studio control rooms
Authors: Moscoso Richard A. , Bistafa Sylvio R.
Published: October 2013

The results of studio-control-room computer simulations with a ray-tracing-type computer program will be presented. Although the validity of ray-tracing simulations of small rooms and at low frequencies may be questionable, the early time echogram at mid and high frequencies obtained by ray tracing provide essential information. Reflections up to 20 ms and frequencies above 500 Hz are responsible for the quality of the listening conditions in studio control rooms, particularly for the assessment of stereophony. Thus, ray-tracing simulations of small rooms for these ranges in the time and frequency domains are justifiable. Computer-generated impulse responses were obtained for different studio-control-room design philosophies as applied to a basic rectangular room. From a simple scrutiny of the impulse responses the characteristics of the initial time delay region could be verified for each design. Traditional room acoustical parameters such as reverberation time and early decay time were analyzed as well as center time Ts, C5, and C20 for the assessment of the spatial impression, timbre, and transparency. The characteristics of each studio-control-room design philosophy will be discussed in light of these results.
Calling and plasticity in Pacific Treefrog choruses
Authors: Brenowitz Eliot A. , Rose Gary J.
Published: October 2013

Male Pacific treefrogs (Hyla regilla) use advertisement and encounter calls to regulate intermale spacing within breeding choruses. Encounter calls are produced when a neighbor’s advertisement calls exceed a threshold amplitude. These aggressive thresholds are plastic; males resume advertisement calling (i.e., accommodate) to repeated presentation of advertisement calls at amplitudes 4–8 dB above their aggressive threshold. Correspondingly, a male’s aggressive threshold for the advertisement call is positively correlated with the maximum amplitude of neighbors advertisement calls measured at his position. The aggressive thresholds of males for the encounter call are also plastic but not correlated with the maximum call amplitude of their neighbors. This disjunction stems from the fact that males in stable choruses are not regularly exposed to suprathreshold encounter calls. Accommodation to one call type fails to significantly alter a male’s aggressive threshold to the other call type, which suggests that the two call types are processed by discrete neural filters. Plasticity of aggressive thresholds and aggressive signalling appears to be important in balancing the costs and benefits of aggressive behaviors. In phonotaxic studies, females show a strong preference for the advertisement call over the encounter call. Prolonged encounter calling would therefore decrease a male’s chance of mating.
The role of call frequency modulation and the auditory papillae in phonotactic behavior in a dart-poison frog
Authors: Hoedl Walter , Amezquita Adolfo , Narins Peter M.
Published: October 2013

Territorial males of the Brilliant-thighed dart-poison frog, Epipedobates femoralis, are known to present stereotypic phonotactic responses to the playback of conspecific and synthetic calls. Fixed site attachment and a long calling period within an environment of little microclimatic changes render this terrestrial and diurnal pan-Amazonian species a rewarding subject for frog bioacoustics. In field experiments at Aratai, French Guiana, we tested whether the prominent frequency modulation of the advertisement call notes is critical for eliciting phonotactic response. Substitution of the natural upward sweep by either a pure tone within the species frequency range or a reverse sweep did not alter the males’ phonotactic behavior. Playbacks with advertisement calls embedded in high levels of either low-pass or high-pass masking noise designed to saturate either the amphibian (AP) or basilar papilla (BP) showed that male phonotactic behavior in this species is subserved by activation of the BP rather than the AP of the inner ear. [Work supported by grants from Austrian Science Foundation P 11565, P 15345 (WH), and NIH (PMN).]
NOAA efforts in monitoring of low-frequency sound in the global ocean
Authors: Fox Christopher G. , Dziak Robert P. , Matsumoto Haruyoshi
Published: October 2013

Since August 1991, NOAA/PMEL has collected continuous recordings from the U.S. Navy SOSUS arrays in the North Pacific. In May 1996, this effort was expanded through the use of PMEL-developed autonomous hydrophones deployed in the eastern equatorial Pacific, and later to the central North Atlantic between 15N and 35N (March 1999), the Gulf of Alaska (October 1999), and the North Atlantic between 40N and 50N (June 2002). Natural seismicity in the Pacific produces nearly 10000 events per year with source levels exceeding 200 dB (re: 1 micro-Pa @ 1 m), with about 3500 events per year exceeding this level in the North Atlantic. Significant contributions from manmade sources are present throughout the data but have not been quantified. Recordings from North Atlantic arrays are dominated by noise from seismic airgun profilers working offshore Canada, Brazil, and west Africa. In September 2001, a cabled vertical hydrophone array was installed at Pioneer Seamount, offshore central California, which will provide continuous, unclassified acoustic data (in the range of 1–450 Hz) to the research community in real time. Future plans call for the expansion of the NOAA monitoring effort to other opportunities worldwide and making the raw data available to the community via the Internet.
A human vocal utterance corpus for perceptual and acoustic analysis of speech, singing, and intermediate vocalizations
Authors: Gerhard David
Published: October 2013

In this paper we present the collection and annotation process of a corpus of human utterance vocalizations used for speech and song research. The corpus was collected to fill a void in current research tools, since no corpus currently exists which is useful for the classification of intermediate utterances between speech and monophonic singing. Much work has been done in the domain of speech versus music discrimination, and several corpora exist which can be used for this research. A specific example is the work done by Eric Scheirer and Malcom Slaney [IEEE ICASSP, 1997, pp. 1331–1334]. The collection of the corpus is described including questionnaire design and intended and actual response characteristics, as well as the collection and annotation of pre-existing samples. The annotation of the corpus consisted of a survey tool for a subset of the corpus samples, including ratings of the clips based on a speech–song continuum, and questions on the perceptual qualities of speech and song, both generally and corresponding to particular clips in the corpus.
Computer-animated illustrations of vibrations and waves
Authors: Hall Donald E.
Published: October 2013

Under this same title, Bruce Richards presented at the 143rd ASA meeting [J. Acoust. Soc. Am. 111, 2394 (2002)] an admirable set of class demonstrations implemented on a Macintosh computer with C++ and the Mac Toolbox. This has inspired the preparation of a similar package of animations written in BASIC for the PC. They include visualizations of motion and corresponding graphs for plucked and bowed strings, bars and membranes, standing and traveling waves in pipes, and normal modes of cylindrical and conical pipes. The animations correspond closely to illustrations in standard textbooks such as the author’s [Musical Acoustics, Brooks–Cole, 3rd ed., 2002].
Single bubble sonoluminescence: Unstable diffusion and the kinetics of chemical reactions
Authors: Holzfuss Joachim
Published: October 2013

Sonoluminescence of a single bubble in water driven by ultrasound is accompanied by long-term stability of the radial bubble wall oscillation. However, in a certain parameter range instabilities of the phenomenon are observed. They are characterized by growing of the ambient (and maximum) radius of the bubble and a sudden microbubble split-off with spatial dislocation (recoil). Experimental results using images of shock waves shed into the surrounding water at bubble collapse are shown to visualize the effect. Numerical calculations show that the observed nonlinear dynamical effects can be interpreted by the influence of diffusional, chemical, and spatial instabilities of the bubble.
Dispersion relation measurements of acoustic waves in bubbly water
Authors: Orris Gregory J. , Nicholas Michael
Published: October 2013

Recent theoretical work on the propagation of acoustic waves in bubbly media has highlighted the need for more precise and modern measurements of the relationship between the phase speed and attenuation in bubbly media. During the engineering tests of the new Salt-Water Tank Facility at the Naval Research Laboratory measurements of the dispersion of acoustic waves in fresh water were performed over a broad range of environmental conditions under semi-free field conditions. Large aqua-culture aeration tubes were used to create bubble clouds completely filling the facility with bubbles whose radii ranged from a few tens of microns to 1 cm with total void fractions that reached to a few percent. We discuss these experimental results within the context of current theories and their implications on ocean acoustic experiments. [Work supported by ONR.]
Hydroacoustical interaction of bubble clouds
Authors: Luther Stefan , Lohse Detlef
Published: October 2013

Acoustically driven cavitation bubble fields consist of typically 104 micron-sized bubbles. Due to their nonlinear hydroacoustical interaction, these extended multiscale systems exhibit the phenomenon of spatiotemporal structure formation. Apart from its significance for the theory of self-organization, it plays a major role in design and control of many industrial and medical applications. Prominent examples are ultrasound cleaning, sono-chemistry and medical diagnostics. From a fundamental point of view the key question to ask is ‘‘How does the fast dynamics on small length scales determine the global slow dynamics of the bubble field?’’ To clarify the complex interplay of acoustical and hydrodynamical forces acting on the bubbles, we employ high-speed particle tracking velocimetry. This technique allows the three-dimensional reconstruction of the bubbles’ trajectories on small and fast scales as well as the measurement of the bubble density on large and slow scales. A theoretical model is derived that describes the nonlinear radial and translational dynamics of the individual bubbles and their interaction. The numerical solution of this N body problem is presented.
A KC-135 experiment for studying single bubble sonoluminescence: Design, fabrication, and results
Authors: Roy Ronald A. , Holt R. Glynn
Published: October 2013

A detailed description of the design and fabrication of an apparatus to study SBSL on the NASA’s KC-135 parabolic flight aircraft will be presented. The apparatus was used during two recent flights aboard the KC-135 (March and July 2002); data from these flights will be presented. Parameters measured during the flights include the acoustic pressure, ambient pressure, acceleration, bubble size, bubble location, water temperature, and light intensity. All measurements were made in a simultaneous fashion, and time tagged using the time code from a VCR which was used to record video images of the bubble. A review of and comparison to data from other KC-135 SL experiments will also be given. [Work supported by NASA.]
Principles and acoustical foundations of the computer-based hearing screening method
Authors: Skarzynski Henryk , Czyzewski Andrzej , Kostek Bozena
Published: October 2013

The hearing impairment is one of the fastest growing diseases in modern societies. Therefore it is very important to organize screening tests allowing us to find people suffering from this kind of impairment. The computer-based system was designed to conduct hearing screening, mainly in children and youth. The test uses automatic questionnaire analysis, audiometric tone test procedure, and testing speech intelligibility in noise. The starting point of the test is an automatic interview with the individual to be tested. Based on the interview, the electronic questionnaire is filled out. After the questionnaire has been filled out and the specially conceived three tone audiometric test is completed, the mode of the speech-in-noise based test might be selected as appropriate for the specific age. When all the testing is completed, the system ‘‘I CAN HEAR...’’ automatically analyzes the results for every person examined. Based on the number of wrong answers those who may have hearing problems are referred to cooperating medical consulting centers. In the paper foundations and principles of the hearing tests are discussed and results of testing of more than 200000 children with this method are demonstrated.
Tempo discrimination of isochronous tone sequences: The multiple-look model revisited
Authors: Miller Nathaniel , McAuley J. Devin
Published: October 2013

Previous research has shown that increasing the number of intervals in an isochronous tone sequence reduces tempo discrimination thresholds [C. Drake and M. Botte, Percept. Psychophys. 54, 277–286 (1993)]. One question that arises is whether increased tempo sensitivity in this instance is attributed to multiple looks at the standard interval, comparison interval, or both. The present study addressed this question by examining tempo discrimination using isochronous tone sequences that contained variable numbers of standard and comparison intervals. In all cases, participants judged the tempo of the comparison sequence relative to a standard sequence (responding faster or slower). Preliminary results suggest that in some cases increases in tempo sensitivity are more due to repetitions of the comparison interval than to repetitions of the standard. The implications of these findings for theories of auditory tempo discrimination will be discussed.
The effects of aging on spatial hearing in listeners with normal hearing
Authors: Koehnke Janet , Besing Joan , Dunn-Murad Ianthe , Neuvirth Caryn
Published: October 2013

This study was designed to examine the effects of aging on spatial hearing in young, middle-aged, and older adults with normal hearing. In order to determine the onset and progression of age-related changes in spatial hearing, performance was measured for three groups of listeners: 18 to 30 years, 38 to 50 years, and over 60 years. All listeners had hearing thresholds of 25 dB HL or better at octave frequencies from 250 through 8000 Hz. A series of virtual tests were administered including spatial localization in quiet, spatial localization in noise, spatial detection in noise, and speech intelligibility gain. For all of these tests, the source locations and listening environments were simulated using head-related-transfer-functions. Results indicate no clear or consistent differences between the young and middle-aged groups on any of the spatial tasks. In contrast, localization errors, spatial detection thresholds, and speech intelligibility thresholds are poorer for the older listeners than for the young and middle-aged listeners. It is noteworthy that all three groups obtain comparable gain in spatial detection thresholds and speech intelligibility thresholds in some listening conditions when the signal and noise sources are spatially separated. [Work supported by NIH/NIDCD Grant No. DC004402.]
The art of building floor vibration evaluation
Authors: Murray Thomas M.
Published: October 2013

Annoying floor vibration caused by building occupant activity is an increasingly common occurrence. Optimized floor systems and the advent of the electronic office are the main causes. Because humans are very sensitive to vertical movement, especially in quiet environments, careful floor design is required. When this is not done or when the occupancy does not meet the design criteria, complaints are commonly received. The complex nature of human excitations (walking, jumping, running, exercising) makes the evaluation of problem floors as much art as science. Typical floor motions include accelerations caused by frequencies above the human threshold limit, which must be considered in any evaluation. Further, most floor systems exhibit several closely spaced modes, which make remedial measures difficult to implement. Structural modifications, passive control in the form of tuned mass dampers, and active control are all potential remedies but a choice is highly dependent on the particulars of the problem floor and the occupancy. This paper discusses techniques for evaluating human induced floor motion and gives examples of successful and unsuccessful retrofits.
Diagnosing a case of occupant-induced whole building vibration
Authors: Hanagan Linda M.
Published: October 2013

People in the tenth floor office suite of a 10-story building were complaining of annoying floor vibrations. These vibrations were worse on some days than on others and seemed to be emanating from a dance studio on the floor below. The building owners wanted the problem fixed; however, the exact mode of transmission to the tenth floor was, as yet, unknown. Understanding how the vibration was being transmitted was essential to developing a repair solution. Among the possibilities for transmission were a full height partition on the ninth floor, the curtain wall, column flexure, and column shortening. Through vibration testing, it was determined that a whole building mode, with an estimated equivalent mass of almost 1000000 kg, was excited to cause disturbing levels of vibration at the tenth floor with as few as six people jumping on the floor below. Details of the vibration testing are provided.
Vibration sensitivity of a laboratory bench microscope
Authors: Amick Hal , Stead Matthew
Published: October 2013

Bench-mounted optical microscopes have a wide variety of applications in science and technology. The vibration sensitivity is a function of both magnification and support conditions. In this paper we present the results of experimental studies addressing vibration sensitivity as well as the amplification and attenuation provided by typical laboratory casework. The benchtop vibration amplitudes at which the effects of motion first become perceptible were found for magnifications of 40×, 100×, 400×, and 1000× using sinusoidal excitation. Frequency response functions were determined for benchtop motion with respect to floor motion, using both conventional casework and a popular pneumatic isolation bench. Floor vibration criteria were developed for microscopes with the two types of support.
Methodology for analyzing spectral differences
Authors: Rothman Howard , Diaz Jose
Published: October 2013

The human voice can be an exceptional instrument. The larynx contributes significantly to making up the exceptional voice: it provides the speaking/singing fundamental frequency (SFF) and the resultant harmonic structure. The vocal tract modulates energy and enhances the contributions of the larynx. There is evidence that the singers/speakers formant provides brilliance and increased amplitude to the voice. Several papers have examined the effects of the spectrum on the perception of the aging voice, the charismatic voice and the professional voice. Spectral differences can be seen in voices that have been identified as good/bad, young/old, brilliant/ordinary. One of the authors presented data differentiating between good and bad vibrato samples that aid in identifying singers that are experiencing vocal difficulty. However, there are singers, identified by vocal pedagogues, critics and other singers as experiencing vocal difficulty, whose vibrato remained unchanged over time. While changes in vibrato are most probably laryngeal in nature, there are no data available as to the changes in the spectra of these singers that provide the perceptual cue for their vocal problems. This paper will present methods detailing the spectral differences and their contributions to perceptual judgments.
Graphical models and automatic speech recognition
Authors: Bilmes Jeff A.
Published: October 2013

Graphical models (GMs) are a flexible statistical abstraction that has been successfully used to describe problems in a variety of different domains. Commonly used for ASR, hidden Markov models are only one example of the large space of models constituting GMs. Therefore, GMs are useful to understand existing ASR approaches and also offer a promising path towards novel techniques. In this work, several such ways are described including (1) using both directed and undirected GMs to represent sparse Gaussian and conditional Gaussian distributions, (2) GMs for representing information fusion and classifier combination, (3) GMs for representing hidden articulatory information in a speech signal, (4) structural discriminability where the graph structure itself is discriminative, and the difficulties that arise when learning discriminative structure (5) switching graph structures, where the graph may change dynamically, and (6) language modeling. The graphical model toolkit (GMTK), a software system for general graphical-model based speech recognition and time series analysis, will also be described, including a number of GMTK’s features that are specifically geared to ASR.
Geoacoustic inversion using genetic algorithm
Authors: Morishita Itaru , Murakami Hirotaka , Ohta Kazuhiko , Okabe Kouki , Oikawa Masamichi
Published: October 2013

Geoacoustic parameters of bottom sediment have a great influence on acoustic propagation in a water column. In order to estimate the parameters, the genetic algorithm (GA) was applied to the low frequency acoustic data obtained at the SWAT (Shallow Water Acoustic Technology) experiments which were conducted at the East China Sea and the New Jersey Shelf. In the experiments, complex acoustic pressure were measured while distance between the source, which transmitted the cw signal, and the receiver was changed. Horizontal wave number spectrum were obtained from the measured data by synthetic aperture process and the Hankel transform. For estimating geoacoustic parameters, an error function was defined as the difference between the measured spectrum and a calculated one which is obtained by applying the Hankel transform to calculated complex pressure, and GA searched geoacoustic parameters which minimize the error. To evaluate the estimated parameters, transmission loss was calculated using the parameters and was compared with measured data.
Finite-element technique for multi-fluid 3-D two-way propagation in ocean waveguides
Authors: Zampolli Mario , Jensen Finn B. , Burnett David S. , Ferla Carlo M.
Published: October 2013

A finite-element technique is presented which makes it possible to treat 3-D forward- and backward scattering in underwater waveguides with inhomogeneous layers of fluid and sediment of arbitrary geometry. The finite-element multi-fluid scattering model was derived from the linear wave equation via the Galerkin residual formulation. From the numerical model, software was developed by customizing an hp-adaptive finite-element package developed by COMCO/Altair Engineering in Austin, Texas. Based on automatic error estimation, it is possible to adapt the user-supplied inhomogeneous computational mesh by making the element size smaller, so-called h-refinement, and/or by increasing the order of the approximating polynomials, so-called p-enrichment, in selected regions of the domain. This process is repeated until a desired level of accuracy in the numerical solution is eventually achieved. The code is validated against a coupled normal-mode model for two-dimensional geometries, and results for shallow-water two-way propagation and scattering with strongly three-dimensional features are presented. The finite-element software is particularly useful for the prediction of scattering from geometries with high local complexity, and as a benchmarking tool for possible future three-dimensional underwater-propagation models.
The accidental (acoustical) tourist
Authors: Van Kirk Wayne
Published: October 2013

The acoustical phenomenon observed at an ancient temple in the Great Ball Court at Chichen Itza was described as ‘‘little short of amazing—an ancient whispering gallery’’ by Silvanus G. Morley, leader of the Carnegie Institute’s archaeological team that excavated and restored these structures in the 1920s. Since then, many others have experienced the extraordinary acoustics at Chichen Itza and other Maya sites. Despite these reports, archaeologists and acousticians have until recently shown little interest in understanding these phenomena. After experiencing Chichen Itza’s remarkable acoustics as a tourist in 1994, the author commenced collecting and disseminating information about acoustical phenomena there and at other Mayan sites, hoping to stimulate interest among archaeologists and acousticians. Were these designs accidental or intentional? If intentional, how was the knowledge obtained? How were acoustical features used? This paper highlights the author’s collection of anecdotal reports of mysterious Mayan acoustics (http://www.ianlawton.com/pal.htm), recommended reading for scientists and engineers who wish to pursue this fascinating study. Also recounted are some of the reactions of archaeologists—ranging from curious, helpful, and insightful to humorous and appalling—to outsiders’ efforts to bring serious scientific attenation to the new field of acoustical archaeology.
Tonal response on the stairway of the main pyramid at La Ciudadela, Teotihuacan archaeological site
Authors: Beristain Sergio , Coss Cecilia , Aquino Gabriela , Negrete Jose , Lizana Pablo
Published: October 2013

This paper presents new research on the very interesting audible effects produced by the stairways of many archaeological sites in Mexico. This investigation was made at the main stairway of the pyramid at La Ciudadela, Teotihuacan archaeological site. The effect previously studied was a chirped echo reflected from the stairway at normal incidence, which resembles the singing of the Quetzal. Now it is presented with the impulsive sound source and the listeners located at different angles, where apart from the characteristic chirped sound, several musical notes could be obtained and identified, covering a range of at least one half an octave. This evaluation was made at the site, where the effect is clearly audible, and it is supported with simple mathematics.
Acoustical features of two Mayan monuments at Chichen Itza: Accident or design?
Authors: Lubman David
Published: October 2013

Chichen Itza dominated the early postclassic Maya world, ca. 900–1200 C.E. Two of its colossal monuments, the Great Ball Court and the temple of Kukulkan, reflect the sophisticated, hybrid culture of a Mexicanized Maya civilization. The architecture seems intended for ceremony and ritual drama. Deducing ritual practices will advance the understanding of a lost civilization, but what took place there is largely unknown. Perhaps acoustical science can add value. Unexpected and unusual acoustical features can be interpreted as intriguing clues or irrelevant accidents. Acoustical advocates believe that, when combined with an understanding of the Maya worldview, acoustical features can provide unique insights into how the Maya designed and used theater spaces. At Chichen Itza’s monuments, sound reinforcement features improve rulers and priests ability to address large crowds, and Ball Court whispering galleries permit speech communication over unexpectedly large distances. Handclaps at Kukulkan stimulate chirps that mimic a revered bird (‘‘Kukul’’), thus reinforcing cultic beliefs. A ball striking playing field wall stimulates flutter echoes at the Great Ball Court; their strength and duration arguably had dramatic, mythic, and practical significance. Interpretations of the possible mythic, magic, and political significance of sound phenomena at these Maya monuments strongly suggests intentional design.
Navajo oral history of a pre-Columbian amphitheater in Chaco Canyon, New Mexico
Authors: Blackhorse Taft , Williams Jay S.
Published: October 2013

A large performance space attached to a natural amphitheater in the cliff face has recently been identified at the center of the pre-Columbian Chaco Complex in Chaco Canyon, New Mexico. This location is known in the ceremonial history of the Navajo people (Din) as Tsbiinaholtsa Yalti (Concavity in Bedrock that Speaks). Tsbiinaholtsa Yalti is a portal to the dimension of the deities and it is opened by way of tonally induced acousma. The physical manifestation of the amphitheater and its acoustical properties invoke the concepts of Tal (Chants) and Taal (Ceremonial pathway). Navajo ceremonies are called Haataal and religious practitioners Hataalii (Chanters). The origin of the tones which give power to contemporary Navajo chants may be traced to the Tsbiinaholtsa Yalti. These tones are produced vocally and are accompanied by the shell trumpet, eagle bone whistle, and reed flute (jadzoosh).
The effects of selective inner hair cell loss on auditory evoked potentials recorded from multiple levels of the auditory system of the unanesthetized chinchilla
Authors: Burkard Robert
Published: October 2013

Most animal models of sensorineural hearing loss show either selective outer hair cell (OHC) loss, or combined OHC and inner hair cell (IHC) loss. Several years ago, Robert Harrison and colleagues discovered that carboplatin could produce a selective IHC loss in the chinchilla. Carboplatin is a second-generation, platinum-based anti-neoplastic agent. In chinchillas, the effect of carboplatin administered systemically is dose dependent, and for the appropriate dosage, produces selective, patchy IHC loss that extends the length of the cochlea. As the vast majority of auditory-nerve afferents innervate the IHCs, this patchy IHC loss due to carboplatin leads to a partial deafferentation of the cochlea. This invited presentation will review a series of studies investigating near-field auditory evoked potentials in the chinchilla that have been performed at the University at Buffalo by the author and his colleagues. Chronic electrode implantation combined with passive animal restraint allow us to record from unanesthetized animals, thus avoiding the confounding effects of anesthesia. Responses from multiple levels of the nervous system (e.g., round window, auditory nerve, inferior colliculus, auditory cortex) will be reported, comparing responses before and after inducing partial IHC loss. [Work supported by NIH NICDC DC03600.]
Models of birdsong learning
Authors: Margoliash Daniel
Published: October 2013

The study of birdsong learning and the passerine song system represents an excellent opportunity to understand how complex acoustic perceptions are represented in the brain, and how these interact with motor systems to produce learned behavior. Recent advances suggesting specific functional roles for different nuclei within the song system help to constrain proposed models of the sensorimotor phase of learning. In particular, a descending motor pathway organized in a temporal hierarchy is involved in motor programming whereas an anterior forebrain basal ganglialike pathway may provide auditory and motor feedback-mediated error signals to adjust the motor pathway. A separate pathway outside of the song system may be devoted to perception of conspecific songs. Central to the problem of vocal learning is the time delay between motor command and auditory feedback. Both real time online models and offline models have been proposed as solutions to the temporal credit assignment problem. The models differ in the types of synaptic mechanisms envisioned that involve forward predictions, and the relative importance of state dependency of song system activity and song learning. Recent data will be given that describe the insight into neural solutions to these problems.
Phase sensitivity of auditory brain-stem responses in echolocating big brown bats
Authors: Ferragamo Michael J. , Sanderson Mark I. , Simmons James A.
Published: October 2013

Multiple behavioral experiments show that echolocating big brown bats perceive 180° phase shifts of ultrasonic (20–100 kHz) FM echoes as delay changes of ±15 μm. These bats represent FM sweeps as coherent auditory spectrograms in which low-pass smoothing of half-wave-rectified hair-cell excitation is the critical limiting parameter. Computational modeling of auditory spectrograms combined with Monte Carlo simulation of echo delay psychophysics reveals that coherence is preserved when the auditory low- pass smoothing cutoff is as low as 7–10 kHz, which is not nearly as high as the 20- to 50-kHz ultrasonic frequencies that seem necessary intuitively. Local-field-potential recordings from the bat’s auditory brain-stem are sensitive to the starting phase of tone-bursts at frequencies up to 14 kHz, manifested as a change in LFP wave-form shape with phase. For most sites this phase sensitivity exhibits a strong dependence on stimulus amplitude. Typically, tone-bursts of 65–75 dB SPL evoke significant changes in LFP responses across different phase conditions. These results appear to confirm that low-pass smoothing in the bat’s auditory transduction process occurs at higher frequencies than for most mammals, and at frequencies that have the ability to confer coherence on the resulting auditory representation of biosonar echoes.
Compact self-focusing piezoelectric shock wave generator using electrically prestressed transducer
Authors: Cathignol Dominique , Birer Alain , Ghohestani Mohammad
Published: October 2013

Compact piezoelectric shock heads need to increase the pressure at the surface of the shell. However, the pressure is limited by the possible mechanical breakdown. So, we have proposed to electrically pre-stress the piezoelectric material by applying an electric field in the opposite direction of the polarization. Using this method, it was possible to reach, on a plane piston, a 5 MPa pressure value. According to this idea, a very compact shock wave generator made of a 1–3 piezocomposite material having a diameter and a focal length of 120 mm was developed. The maximum pressure and the width of the compressive wave at the focus were, respectively, 60 MPa and 1.5 microseconds. The focal zone is an ellipsoid 6 mm in the propagating axis and 3 mm in the perpendicular direction. The efficacy of this generator was measured as the number of shocks necessary to disintegrate plaster balls 15 mm in diameter. At full power, the number of shocks was only 150 which is rather the same number as the one obtained using electrohydraulic machine generally considered as the gold standard. These results show that piezoelectric material may be advantageously used for the manufacturing of shock wave generators.
From air to rubber: New techniques for measuring and replicating mouthpieces, bocals, and bores
Authors: Fuks Leonardo
Published: October 2013

The history of musical instruments comprises a long genealogy of models and prototypes that results from a combination of copying existing specimens with the change in constructive parameters, and the addition of new devices. In making wind instruments, several techniques have been traditionally employed for extracting the external and internal dimensions of toneholes, air columns, bells, and mouthpieces. In the twentieth century, methods such as pulse reflectometry, x-ray, magnetic resonance, and ultrasound imaging have been made available for bore measurement. Advantages and drawbacks of the existing methods are discussed and a new method is presented that makes use of the injection and coating of silicon rubber, for accurate molding of the instrument. This technique is harmless to all traditional materials, being indicated also for measurements of historical instruments. The paper presents dimensional data obtained from clarinet and saxophone mouthpieces. A set of replicas of top quality clarinet and saxophone mouthpieces, trombone bocals, and flute headjoints is shown, with comparative acoustical and performance analyses. The application of such techniques for historical and modern instrument analysis, restoration, and manufacturing is proposed.
Impedance comparison of high-quality alto and soprano saxophones
Authors: Gibiat Vincent , Selmer Jerome
Published: October 2013

Measuring the input impedance of high-quality wind instruments requires both a system able to provide the physical quantity in less than a few seconds and the possibility to do the measurement on a wide number of instruments. If we have such a system measuring system giving us the possibility to obtain impedance curves for the whole musical range of the instrument the second condition cannot be achieved without the strong collaboration of an instrument maker. The present study has been realized on Selmer saxophones and on instrmuents from two other factories. They include vintage instruments (as Mark VI) and the most recent commercialized ones. It allows one to study the evolution of the instruments. We will show that some alto saxophone models have reached an incredible harmonicity of their resonances while less common models present other characteristics. We will discuss these results and their relations with the audible quality of the instruments.
International hearing protector standardization
Authors: Poulsen Torben
Published: October 2013

Hearing protectors shall fulfill some minimum requirements to their performance. As hearing protector manufacturers sell the products all over the world, the testing and certification of hearing protectors has become an international issue. The ISO working group WG17 under the headlines Acoustics, Noise, produce hearing protector standards to be used at an international level. The presentation will cover the ongoing work in WG17, including the revision of existing standards (ISO 4869-1, ISO 4869-3), upcoming new standards (ISO 4869-7) and the plans and status for future standards (performance in impulse noise, protectors with active noise reduction). Furthermore, an overview of the present European standards (CEN) and the relation to American and Australian/New Zealand standards will be discussed.
Issues regarding hearing protection device use in manufacturing and mining
Authors: Morata Thais
Published: October 2013

In this study reasons offered by workers for not consistently using hearing protectors are examined. Study groups were comprised of: (1) 124 workers exposed to various levels of noise in a manufacturing company, located in Sao Paulo, Brazil. Data on work history, psychosocial aspects of the workers job, medical history, present health, stress, occupational and nonoccupational exposures to noise or chemicals, and lifestyle factors were collected through interviews. The participants had their hearing and noise exposure assessed. Sixty-four percent of the workers indicated that they wore hearing protectors, but only 20 percent of that subgroup stated that they wore the devices all the time when noise-exposed. (2) Forty-four workers and supervisors from the manufacturing and mining sectors in Cincinnati and Pittsburgh. Participants were interviewed or took part in focus groups discussions on a variety of hearing conservation topics, including problems with the use of HPDs. The variables significantly associated with a workers’ decision not to wear hearing protectors consistently included interference with communication, interference with job performance, comfort issues, self-perception of hearing condition, and inability to detect warning signals when wearing HPDs. These are issues to be addressed in order to promote a more effective use of HPDs.
Long codas of coupled wave systems in seismic basins
Authors: Seligman Thomas H.
Published: October 2013

Quite some time ago it was pointed out that the damage patterns and Fourier spectra of the 1985 earthquake in Mexico City are only compatible with a resonant effect of horizontal waves with the approximate speed of sound waves in water [see Flores et al., Nature 326, 783 (1987)]. In a more recent paper it was pointed out that this indeed will occur with a very specific frequency selection for a coupled system of Raleigh waves at the interface of the bottom of the ancient lakebed with the more solid deposits, and an evanescent sound wave in the mud above [see J. Flores et al., Bull. Seismol. Soc. Am. 89, 14–21 (1999)]. In the present talk we shall go over these arguments again and show that strong reflection at the edges of the lake must occur to account for the strong magnification entailing necessarily a long coda, and that the mecanism can be understood in the same terms.