bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptual sensitivity to first harmonic amplitude in the voice source
Authors: Kreiman Jody , Gerratt Bruce R.
Published: October 2010

Little is known about the perceptual importance of changes in the shape of the source spectrum, although many measures have been proposed and correlations with different vocal qualities (breathiness, roughness, nasality, strain…) have frequently been reported. This study investigated just-noticeable differences in the relative amplitudes of the first two harmonics (H1–H2) for speakers of Mandarin and English. Listeners heard pairs of vowels that differed only in the amplitude of the first harmonic and judged whether or not the voice tokens were identical in voice quality. Across voices and listeners, just-noticeable-differences averaged 3.18 dB. This value is small relative to the range of values across voices, indicating that H1–H2 is a perceptually valid acoustic measure of vocal quality. For both groups of listeners, differences in the amplitude of the first harmonic were easier to detect when the source spectral slope was steeply falling so that F0 dominated the spectrum. Mandarin speakers were significantly more sensitive (by about 1 dB) to differences in first harmonic amplitudes than were English speakers. Two explanations for these results are possible: Mandarin speakers may have learned to hear changes in harmonic amplitudes due to changes in voice quality that are correlated with the tones of Mandarin; or Mandarin speakers’ experience with tonal contrasts may increase their sensitivity to small differences in the amplitude of F0 (which is also the first harmonic).
Musical intervals and relative pitch: Frequency resolution, not interval resolution, is special
Authors: McDermott Josh H. , Keebler Michael V. , Micheyl Christophe , Oxenham Andrew J.
Published: October 2010

Pitch intervals are central to most musical systems, which utilize pitch at the expense of other acoustic dimensions. It seemed plausible that pitch might uniquely permit precise perception of the interval separating two sounds, as this could help explain its importance in music. To explore this notion, a simple discrimination task was used to measure the precision of interval perception for the auditory dimensions of pitch, brightness, and loudness. Interval thresholds were then expressed in units of just-noticeable differences for each dimension, to enable comparison across dimensions. Contrary to expectation, when expressed in these common units, interval acuity was actually worse for pitch than for loudness or brightness. This likely indicates that the perceptual dimension of pitch is unusual not for interval perception per se, but rather for the basic frequency resolution it supports. The ubiquity of pitch in music may be due in part to this fine-grained basic resolution.
Subjective scaling of spatial room acoustic parameters influenced by visual environmental cues
Authors: Valente Daniel L. , Braasch Jonas
Published: October 2010

Although there have been numerous studies investigating subjective spatial impression in rooms, only a few of those studies have addressed the influence of visual cues on the judgment of auditory measures. In the psychophysical study presented here, video footage of five solo music/speech performers was shown for four different listening positions within a general-purpose space. The videos were presented in addition to the acoustic signals, which were auralized using binaural room impulse responses (BRIR) that were recorded in the same general-purpose space. The participants were asked to adjust the direct-to-reverberant energy ratio (D/R ratio) of the BRIR according to their expectation considering the visual cues. They were also directed to rate the apparent source width (ASW) and listener envelopment (LEV) for each condition. Visual cues generated by changing the sound-source position in the multi-purpose space, as well as the makeup of the sound stimuli affected the judgment of spatial impression. Participants also scaled the direct-to-reverberant energy ratio with greater direct sound energy than was measured in the acoustical environment.
Difference in precedence effect between children and adults signifies development of sound localization abilities in complex listening tasks
Authors: Litovsky Ruth Y. , Godar Shelly P.
Published: October 2010

The precedence effect refers to the fact that humans are able to localize sound in reverberant environments, because the auditory system assigns greater weight to the direct sound (lead) than the later-arriving sound (lag). In this study, absolute sound localization was studied for single source stimuli and for dual source lead-lag stimuli in 4–5 year old children and adults. Lead-lag delays ranged from 5–100 ms. Testing was conducted in free field, with pink noise bursts emitted from loudspeakers positioned on a horizontal arc in the frontal field. Listeners indicated how many sounds were heard and the perceived location of the first- and second-heard sounds. Results suggest that at short delays (up to 10 ms), the lead dominates sound localization strongly at both ages, and localization errors are similar to those with single-source stimuli. At longer delays errors can be large, stemming from over-integration of the lead and lag, interchanging of perceived locations of the first-heard and second-heard sounds due to temporal order confusion, and dominance of the lead over the lag. The errors are greater for children than adults. Results are discussed in the context of maturation of auditory and non-auditory factors.
Change in echolocation signals with hearing loss in a false killer whale (Pseudorca crassidens)
Authors: Kloepper Laura N. , Nachtigall Paul E. , Breese Marlee
Published: October 2010

The echolocation signals of a false killer whale (Pseudorca crassidens) were collected during a wall thickness discrimination task and compared to clicks recorded during an identical experiment in 1992. During the sixteen year time period, the subject demonstrated a loss of high frequency hearing of about 70 kHz. Clicks between the two experiments were compared to investigate the effect of hearing loss on echolocation signals. There was a significant reduction in the peak frequency, center frequency and source level of clicks between the two time periods. Additionally, the subject currently produces more signals with low frequency peaks and fewer signals with high frequency peaks than she did in 1992. These results indicate the subject changed its echolocation signals to match its range of best hearing.
Trading of intensity and interaural coherence in dichotic pitch stimuli
Authors: Culling John F. , Lewis Hannah G.
Published: October 2010

When a signal is added to noise in the NoSπ binaural configuration, a reduction in interaural coherence, ρ, occurs at the signal frequency and increases in tone intensity decrease ρ. Corresponding manipulations of ρ result in the perception of a phantom signal which increases in loudness as ρ decreases [Culling et al. (2001). J. Acoust. Soc. Am. 110, 1020–1029]. In the present study, a narrow sub-band of noise (462–539 Hz) embedded within a broadband (0–3 kHz) diotic noise was manipulated in both intensity and ρ in a 3-interval, odd-one-out task. In the reference intervals, ρ was zero and the spectrum was flat. In the target interval, both ρ and the intensity of the target band were incremented giving opposing effects on loudness. Correct identification of the target interval followed a V-shape as a function of the size of intensity increment. The minimum of this function was often at chance performance, indicating that monaurally and binaurally evoked loudness were fully traded. These results show that reduction in ρ at a given frequency produces increased loudness at that frequency equivalent to up to 6 dB and consistent with an equalization-cancellation mechanism whose binaural output is strongly weighted compared to monaural excitation.
Variation in the resting frequency of Rhinolophus pusillus in Mainland China: Effect of climate and implications for conservation
Authors: Jiang Tinglei , Metzner Walter , You Yuyan , Liu Sen , Lu Guanjun , Li Shi , Wang Lei , Feng Jiang
Published: October 2010

This study describes variation patterns in the constant frequency of echolocation calls emitted at rest and when not flying (“resting frequency” RF) of the least horseshoe bat, Rhinolophus pusillus, on a broad geographical scale and in response to local climatic variables. Significant differences in RF were observed among populations throughout the species range in Mainland China, and this variation was positively and significantly related to climate conditions, especially environmental humidity, but the variability was only weakly associated with geographical distance. Sex dimorphism in the RF of R. pusillus may imply that female and male might keep their frequencies within a narrow range for sex recognition. Moreover, bats adjusted resting frequency to humidity, which may imply partitioning diet by prey size or the influence of rainfall noise. The results indicate that bats adjust echolocation call frequency to adapt to environmental conditions. Therefore, environmental selection shape the diversity of echolocation call structure of R. pusillus in geographically separated populations, and conservation efforts should focus on changes in local climate and effects of environmental noise.
Impact of three hours of discotheque music on pure-tone thresholds and distortion product otoacoustic emissions
Authors: Müller Jörg , Dietrich Susanne , Janssen Thomas
Published: October 2010

The aim of this study was to investigate whether distortion product otoacoustic emissions (DPOAEs) are a suitable means for detecting changes in outer hair cell (OHC) functionality due to exposure to three hours of discotheque music and whether efferent reflex strength of the medial olivocochlear bundle is able to predict the ear’s susceptibility to high-level noise. High-resolution DPOAEs (Δf2=47 Hz) were recorded between 3.5 and 4.5 kHz at close-to-threshold primary tone levels. For comparison, high-resolution pure-tone audiometry was conducted in the same frequency range. Efferent reflex strength was measured by means of DPOAEs at a specific frequency with and without contralateral acoustic stimulation. A significant deterioration of more than 10 dB was found for pure-tone thresholds and DPOAE levels indicating that three hours of high-level noise exert a considerable influence on hearing capability and OHC functionality. A significant correlation between shifts in pure-tone threshold and shifts in DPOAE level occurred when removing data with differing calibration across measurements. There was no clear correlation between efferent reflex strength and shifts in pure-tone threshold or shifts in DPOAE level suggesting that the applied measures of efferent reflex strength may not be suitable for quantifying individual vulnerability to noise.
Constraining the minute amount of audible energy radiated from binary collisions of light plastic spheres in conditions of incomplete angular coverage of the measured pressure
Authors: Petculescu Andi , Riner Joshua
Published: October 2010

Usually, the energy released as air-coupled sound following a collision is dismissed as negligible. The goal of this Letter is to quantify the value of this small but measurable quantity, since it can be useful to impact studies. Measurements of sound radiation from binary collisions of polypropylene balls were performed in order to constrain the fraction of incident energy radiated as sound in air. In the experiments, one ball is released from rest, directly above a stationary target ball. The transient acoustic waveforms are detected by a microphone rotated about the impact point at a radius of 10 cm. The sound pressure was measured as a function of the polar angle θ (the azimuthal symmetry of the problem was verified by rotating the microphone in the horizontal plane). The angular pattern has two main lobes that are asymmetric with respect to the impact plane. This asymmetry is ascribable to interference and/or scattering effects. Gaps in the acoustic measurements at the “poles” (i.e., around 0° and 180°) pose a challenge similar to that of extrapolating the cosmic microwave background in the galactic “cut.” The data was continued in the gaps by polynomial interpolation rather than least-squares fitting, a choice dictated by the accuracy of the reconstructed pattern. The acoustic energy radiated during the impact, estimated by multiplying the collision time by the sound intensity integrated over a spherical surface centered at the impact point, is calculated as four orders of magnitude smaller than the incident energy (0.23 μJ versus 1.6 mJ).
Adaptive auditory feedback control of the production of formant trajectories in the Mandarin triphthong /iau/ and its pattern of generalization
Authors: Cai Shanqing , Ghosh Satrajit S. , Guenther Frank H. , Perkell Joseph S.
Published: October 2010

In order to test whether auditory feedback is involved in the planning of complex articulatory gestures in time-varying phonemes, the current study examined native Mandarin speakers' responses to auditory perturbations of their auditory feedback of the trajectory of the first formant frequency during their production of the triphthong /iau/. On average, subjects adaptively adjusted their productions to partially compensate for the perturbations in auditory feedback. This result indicates that auditory feedback control of speech movements is not restricted to quasi-static gestures in monophthongs as found in previous studies, but also extends to time-varying gestures. To probe the internal structure of the mechanisms of auditory-motor transformations, the pattern of generalization of the adaptation learned on the triphthong /iau/ to other vowels with different temporal and spatial characteristics (produced only under masking noise) was tested. A broad but weak pattern of generalization was observed; the strength of the generalization diminished with increasing dissimilarity from /iau/. The details and implications of the pattern of generalization are examined and discussed in light of previous sensorimotor adaptation studies of both speech and limb motor control and a neurocomputational model of speech motor control.
On the angular error of intensity vector based direction of arrival estimation in reverberant sound fields
Authors: Levin Dovid , Habets Emanuël A. P. , Gannot Sharon
Published: October 2010

An acoustic vector sensor provides measurements of both the pressure and particle velocity of a sound field in which it is placed. These measurements are vectorial in nature and can be used for the purpose of source localization. A straightforward approach towards determining the direction of arrival (DOA) utilizes the acoustic intensity vector, which is the product of pressure and particle velocity. The accuracy of an intensity vector based DOA estimator in the presence of noise has been analyzed previously. In this paper, the effects of reverberation upon the accuracy of such a DOA estimator are examined. It is shown that particular realizations of reverberation differ from an ideal isotropically diffuse field, and induce an estimation bias which is dependant upon the room impulse responses (RIRs). The limited knowledge available pertaining the RIRs is expressed statistically by employing the diffuse qualities of reverberation to extend Polack’s statistical RIR model. Expressions for evaluating the typical bias magnitude as well as its probability distribution are derived.
Multistatic detection and tracking using linear maximal sequences
Authors: Jobst W. , Smith D. , Whited L.
Published: October 2010

A simulation using linear maximal sequence (m-sequence) transmissions demonstrated the potential for detecting and tracking near-surface targets. In this simulation a low power, omnidirectional source and four omnidirectional hydrophones were arbitrarily located in water approximately 4 m deep. The simulated −15 dB target traveled at 1.5 kn. Using “channel digit response” processing and “block zeroing,” the direct arrival, multipaths, clutter and reverberation were rejected. (The block zeroing process is very different from other methods typically labeled as “cancellation.”) With the improved signal-to-interference ratio, a simple probability based algorithm demonstrated tracking at source-target distances of 250 m, the maximum range investigated.
Long range transmission loss of broadband seismic pulses in the Arctic under ice-free conditions
Authors: Thode Aaron , Kim Katherine H. , Greene Charles R. , Roth Ethan
Published: October 2010

In 2008 the Louis S. St-Laurent (LSSL) surveyed deep Arctic waters using a three-airgun seismic source. Signals from the seismic survey were detected between 400 km and 1300 km range on a directional autonomous acoustic recorder deployed in water 53 m deep off the Alaskan North Slope. Observations of received signal levels between 10–450 Hz versus LSSL range roughly fit a cylindrical transmission loss model plus 0.01 dB/km attenuation in deep ice-free waters, and fit previous empirical models in ice-covered waters. The transition between ice-free and ice-covered propagation conditions shifted 200 km closer to the recorder during the survey.
Modeling cochlear dynamics: Interrelation between cochlea mechanics and psychoacoustics
Authors: Epp Bastian , Verhey Jesko L. , Mauermann Manfred
Published: October 2010

A model of the cochlea was used to bridge the gap between model approaches commonly used to investigate phenomena related to otoacoustic emissions and more filter-based model approaches often used in psychoacoustics. In the present study, a nonlinear and active one-dimensional transmission line model was developed that accounts for several aspects of physiological data with a single fixed parameter set. The model shows plausible excitation patterns and an input-output function similar to the linear-compressive-linear function as hypothesized in psychoacoustics. The model shows realistic results in a two-tone suppression paradigm and a plausible growth function of the 2f1−f2 component of distortion product otoacoustic emissions. Finestructure was found in simulated stimulus-frequency otoacoustic emissions (SFOAE) with realistic levels and rapid phase rotation. A plausible “threshold in quiet” including finestructure and spontaneous otoacoustic emissions (SOAE) could be simulated. It is further shown that psychoacoustical data of modulation detection near threshold can be explained by the mechanical dynamics of the modeled healthy cochlea. It is discussed that such a model can be used to investigate the representation of acoustic signals in healthy and impaired cochleae at this early stage of the auditory pathway for both, physiological as well as psychoacoustical paradigms.
Manipulation of microparticles using phase-controllable ultrasonic standing waves
Authors: Courtney C. R. P. , Ong C.-K. , Drinkwater B. W. , Wilcox P. D. , Demore C. , Cochran S. , Glynne-Jones P. , Hill M.
Published: October 2010

A method of manipulating microparticles in a liquid using ultrasound is proposed and demonstrated. An ultrasonic standing wave with nodal planes whose positions are controllable by varying the relative phase of two applied sinusoidal signals is generated using a pair of acoustically matched piezoelectric transducers. The resulting acoustic radiation force is used to trap micron scale particles at a series of arbitrary positions (determined by the relative phase) and then move them in a controlled manner. This method is demonstrated experimentally and 5 μm polystyrene particles are trapped and moved in one dimension through 140 μm.
Factors influencing recognition of interrupted speech
Authors: Wang Xin , Humes Larry E.
Published: October 2010

This study examined the effect of interruption parameters (e.g., interruption rate, on-duration and proportion), linguistic factors, and other general factors, on the recognition of interrupted consonant-vowel-consonant (CVC) words in quiet. Sixty-two young adults with normal-hearing were randomly assigned to one of three test groups, “male65,” “female65” and “male85,” that differed in talker (male/female) and presentation level (65/85 dB SPL), with about 20 subjects per group. A total of 13 stimulus conditions, representing different interruption patterns within the words (i.e., various combinations of three interruption parameters), in combination with two values (easy and hard) of lexical difficulty were examined (i.e., 13×2=26 test conditions) within each group. Results showed that, overall, the proportion of speech and lexical difficulty had major effects on the integration and recognition of interrupted CVC words, while the other variables had small effects. Interactions between interruption parameters and linguistic factors were observed: to reach the same degree of word-recognition performance, less acoustic information was required for lexically easy words than hard words. Implications of the findings of the current study for models of the temporal integration of speech are discussed.
Radiated signal characteristics of marine vessels in the cepstral domain for shallow underwater channel
Authors: Das Arnab , Kumar Arun , Bahl Rajendar
Published: October 2010

This work examines the distribution of cepstral energy of the radiated signal of a marine vessel and the underwater channel modeled as a block-adaptive linear system. Detailed simulation analysis of the signal at the receiver of a passive sonar has led to the observation that, in the cepstral domain the radiated signal of a marine vessel largely occupies the lower cepstral indices while the underwater channel occupies the higher indices, such that for several range and depth conditions, the two can be separated out. This finding can facilitate the design of filters in the cepstral domain for reducing distortions due to the underwater channel. The work presents analytical justification and simulation studies in this regard.
End level bias on direct loudness ratings of increasing sounds
Authors: Susini Patrick , Meunier Sabine , Trapeau Régis , Chatron Jacques
Published: October 2010

Three experiments on loudness of sounds with linearly increasing levels were performed: global loudness was measured using direct ratings, loudness change was measured using direct and indirect estimations. Results revealed differences between direct and indirect estimations of loudness change, indicating that the underlying perceptual phenomena are not the same. The effect of ramp size is small for the former and important for the latter. A similar trend was revealed between global loudness and direct estimations of loudness change according to the end level, suggesting they may have been confounded. Measures provided by direct estimations of loudness change are more participant-dependent.
Recent drama theater design experience.
Authors: Eligator Ronald T. , Kahn David W. , Edwards Nicholas
Published: October 2010

The four projects Acoustic Dimensions submitted for inclusion to the “Drama Theatres” book represent a range of design approaches to the challenges inherent in the design of these spaces. This presentation will focus on the approach to finding acoustic design solutions in a collaborative process with the architect, theater consultant, and other design team members as illustrated by our work on the Royal Shakespeare Theatre, RSC Roundhouse, Williams College ‘62 Center for Theatre and Dance, and Woolly Mammoth Theatre.
Understanding the role of direction in thrust and in-the-round theater spaces.
Authors: Hoffman Ian , Talaske Richard , Harrison Byron
Published: October 2010

Successful room acoustic designs for spoken-word drama theater provide both speech clarity and effective localization to all the listening patrons. While clarity relies primarily on the timing, level, and frequency of early reflections between the actor[s] and patrons, effective localization (especially with multiple actors speaking) adds direction and spatial considerations to the pursuit of room acoustic success. In thrust and in-the-round theaters, speech clarity and localization are further challenged by many production-specific variables, including the direction an actor faces when delivering the text. In these spaces, actors frequently deliver lines while facing away from large portions of the audience. Through the lessons of two recent substantial theater renovations, one thrust stage and one in-the-round, this paper will illustrate (some of) the challenges to improving speech clarity and effective localization in dramatic theater spaces with highly non-specific source-receiver conditions, and it will propose an approach for achieving clarity and localization, even amid changing and non-specific actor-listener configurations.
Architectural acoustic design concepts for drama theaters.
Authors: Siebein Gary W. , Paek Hyun , Lilkendey Robert M. , Skelton Reece
Published: October 2010

The application of impulse response theory with architectural design principles provides a foundation for the acoustical design of drama theaters, linking the perceptions of the audience, acoustical measurements made in completed rooms, and acoustical modeling and simulations of rooms being designed. (1) Provide a quiet environment free from exterior and equipment noise; (2) design each interior surface of the room to be acoustically productive by having it contribute essential elements to the idealized impulse response of a drama theater; (3) use layered architectural/acoustic systems that accomplish multiple functions within one assembly that at once provides for sound reflection and diffusion of sounds to the audience on its interior face, reduces sounds from outside the building with its exterior skin, includes space for inlet and attenuation of return air systems within wall cavities, allows transit of HVAC and building structural systems within it, and has a variable layer at its outermost surface that can adjust the interior acoustical response of the room for varying performance types. The construction of the room impulse response element by element as the design of the theater emerges allows a vehicle for the integration of architecture, acoustics, and engineering systems to occur during design.
Sodre auditorium.
Authors: Fernández Gonzalo
Published: October 2010

Sodre Adela Retta Complex is the biggest in its type in Uruguay. The main area, Eduardo Fabini Auditorium, is a multipurpose one, with room for an audience of 2000 people. There are also rehearsal sectors for the orchestra, choir, and ballet, as well as changing rooms and administrative offices. The building of the premises started two decades ago and was carried out in several stages. In October 2008, the main objective of the national government was to focus on the above auditorium, the halls, and the foyers, which were finally opened to the public in November 2009. It is worth mentioning that this project complies with all the necessary acoustic requirements for this type of venue. We will focus on describing the auditorium itself, with emphasis on its acoustic adaptability to different types of artistic performances, the control and supervision process during the last stages of its construction, and the assessment of its acoustic parameters once it started functioning, followed by guidelines and recommendations to fully exploit the acoustics flexibility the auditorium offers.
Preservation of the acoustical quality of the Teatro Colon of Buenos Aires.
Authors: Basso Gustavo Jorge , Haedo Alberto M. , Sanchez Quintana Rafael
Published: October 2010

The general criteria and the works carried out from the year 2004 in order to preserve the acoustical quality of the Teatro Colon of Buenos Aires are described in this paper. The acoustical measurements of the previous state of the hall, the acoustic measurements carried out during its dismantling, the acoustical measurements taken out at laboratory, and the analysis through statistical methods and digital models are shown. This methodology allows us to design the main criteria in order to preserve the acoustical quality of this well-known hall. The criteria used for the selection of materials with acoustic implications are described. Results are shown of the measurements made in the laboratory, of the new acoustic materials, and measurements made in the Auditorium as it was assembled in the opposite sequence it was measured during disassembly. The final measurements of the Auditorium are described and compared to the measurement values obtained before it was closed for restoration. It has been proved that the Colon Theater’s acoustic quality has been preserved.
Overview of underwater acoustic metrics.
Authors: Erbe Christine
Published: October 2010

In this presentation, metrics for the characterization of underwater sound will be discussed. What metrics should be used for continuous sound? What metrics are “best” for transient sound? What metrics are relevant for bioacoustic impact estimation? An overview of the quantities commonly measured and computed will be given, including pressure (peak, root-mean-square), energy, intensity, spectral density, sound exposure level, band level, etc. Differences between metrics will be highlighted. The applicability of the different metrics to various “situations” will be explained and limitations discussed. What determines the “best” set of metrics—the source, the receiver, the environment? How does one decide whether a quantity is “good” or “bad”, useful or not? What other parameters need to be specified to make a quantity reliable, reproducible, and relevant? Examples of underwater sound will be given, and both appropriate and inappropriate metrics will be computed.
Source levels of killer whale calls: Differences among call types and noise levels.
Authors: Holt Marla M. , Noren Dawn P. , Emmons Candice K.
Published: October 2010

Several studies have reported source levels for a variety of sounds produced by animals. This information can then be used to predict the range over which sounds may be used among individuals in communication networks and how the active space of such signals are affected by anthropogenic sounds. Some studies have also shown that animals readily modify parameters of their acoustic signals in response to changes in background sound levels. For instances, killer whales increased their call source level as vessel noise increased. Killer whale calls are likely used for communication among group members and some are population specific being stereotyped, repeated, and structurally distinct. Call source levels also vary depending on call type, but vocal responses to changes in background sound levels were not taken into account. Data were collected on southern resident killer whales (Orcinus orca) using a hydrophone array in waters surrounding the San Juan Islands, WA over three summers. Differences in call source levels as they relate to differences in call type, call structure, and background sound levels will be presented. Such considerations are necessary to accurately predict the range over which animals communicate and how anthropogenic sound exposure affects their use of sound.
Investigating the interaction between ambient acoustics and primate vocalization in the Ecuadorian Amazon: A test of the acoustic adaptation hypothesis.
Authors: Coleman Mark N.
Published: October 2010

Research on the acoustics of African forests has demonstrated that many primate species utilize frequency sound windows that help increase the distance their vocalizations travel. However, other studies on primates and additional animals have found mixed support for the proposal that vocalizations are adapted to the environments in which they are produced (the acoustic adaption hypothesis). This project conducted analyzes of ambient sounds and primate vocalizations in the Ecuadorian Amazon in order to test acoustic adaptation hypothesis. Ambient recordings and sound pressure levels near ground level were collected, which sampled all times of day for a cumulative total of 8 days. In addition, primate vocalizations were collected for 6 of the 9 species of diurnal primates at the research site. Preliminary findings indicate that the majority of ambient noise occurs between 2 and 10 kHz. Below this range there is a substantial decrease in ambient sound and many of the primates broadcast their calls in this window. However, these results suggest a more complex picture than that found in Africa, with some smaller species vocalizing above the main sources of ambient noise. It also appears that there is some degree of frequency separation among the primates studied.
Low-frequency sound generation from breaking waves: Experimental measurements and modeling.
Authors: Means Steven L. , Heitmeyer Richard M.
Published: October 2010

The first at-sea measurements capable of spatially resolving the individual breaking wave contributions at frequencies below 400 Hz, where collective bubble oscillations are believed to be the dominant sound generation mechanism, were conducted in shallow water (200 m) near San Clemente Island in March/April 1995 using a vertical array deployed from the RP/FLIP. The time-frequency structure of the noise generated from individual breaking waves was obtained using the endfire beam of a vertical array along with optical measurements of the locations, sizes, and lifetimes of those breaking waves. Strong acoustic bursts in time coincidence with the larger breaking wave events were observed. Approximately one-third of breaking wave source spectra contained large peaks at 40–60 Hz. Additionally, a theoretical model based on the excitation of an entrained bubble cloud by individual point sources is presented to explain the low-frequency peaks evident in the measured source spectra. Statistical characterizations of the association of breaking-wave size and the broadband acoustic energy will be presented. [Work supported by ONR base funding at NRL.]
Modeling of acoustic reverberation from a diurnally migrating fish aggregation with depth-dependent resonance.
Authors: Jones Benjamin A. , Stanton Timothy K. , Colosi John A.
Published: October 2010

The depth dependence of the resonance frequency of fish with swimbladders is affected by both the change in volume (physostomes only) and pressure of the swimbladder (physostomes and physoclists). Due to these physical processes, the migration of fish upward or downward the water column can cause significant variation in the magnitude of the echoes received by an active sonar, most notably in narrowband applications where the resonance frequency may pass through the sonar band during migration. This variation in received echo level is further complicated by waveguide effects in long-range acoustic scenarios. The sonar simulator toolset, a ray-based sonar simulator, is used to simulate the reverberation of a narrowband, FM pulse by a vertically migrating aggregation of fish over a range of conditions. We examine the results of varying range, depth, and other waveguide parameters on the matched filter output. The predictions distinguish the effect of swimbladder resonance from acoustic waveguide effects on the scattering. A key result illustrated is a 28-dB variation in the received echo due to the resonance frequency passing through the band of a 3-kHz sonar during diurnal migration of the Atlantic herring.
Excitation thresholds for subharmonic response of ultrasound contrast microbubbles.
Authors: Katiyar Amit , Sarkar Kausik
Published: October 2010

Nonlinear dynamics of encapsulated contrast microbubbles generates subharmonic response at stronger acoustic excitations. The response depends on environmental conditions such as ambient pressure. It has therefore been proposed that the subharmonic response could offer a novel means for non-invasive monitoring of organ-level blood pressure. For a free bubble, there exists a threshold excitation pressure for subharmonic response, the threshold being minimum at twice the resonance frequency of the free bubble. The stabilizing encapsulation of a contrast microbubble significantly alters the behavior of a bubble. Several models of encapsulation have been developed and their predictions compared with measured response from contrast microbubbles. Here, we use these models to study the threshold pressure for initiation of subharmonic scattered response. We will show that the encapsulation significantly affects the threshold and the variation of subharmonic response with other parameters such as ambient pressure, excitation, and bubble radius.
Estimation of spatial resolution for high-frequency imaging systems using a novel anechoic-sphere phantom.
Authors: Filoux Erwan , Mamou Jonathan , Aristizábal Orlando , Ketterling Jeffrey A.
Published: October 2010

A new method has been developed to estimate the spatial resolution of high-frequency ultrasound (HFU, >20 MHz) imaging systems in 3-D using a tissue-mimicking phantom (TMP). The TMP is divided into eight adjacent compartments containing anechoic spheres (6 vol %) with diameters increasing from 0.1 to 1.09 mm, suspended in an echogenic background consisting of 3.5-μm-diameter glass beads. The ability of an HFU imaging system to detect these spheres against a speckle background provides a realistic estimation of its minimum 3-D resolution. Here, the TMP was scanned using a 40-MHz single-element transducer and a linear array (VisualSonics™ Vevo 770 and 2100, respectively), and a custom HFU annular-array-based system with a 40-MHz nominal center frequency. Depth-of-field and penetration depth of the custom system were increased using synthetic focusing and chirp-coded excitation. Resulting B-mode images indicated that the custom system could resolve spheres down to 0.2 mm, while the commercial systems resolved spheres down to 0.3 mm. In addition, the annular array provided a larger depth-of-field and higher contrast-to-noise ratios at all depths versus the commercial transducers. [Work supported by NIH Grant EB008606.]
Quantitative Schlieren imaging of continuous and pulsed high-intensity ultrasonic fields using narrow band spatial filters.
Authors: Kaczkowski Peter J. , Bailey Michael R. , Khokhlova Vera A. , Sapozhnikov Oleg A.
Published: October 2010

The Schlieren method of visualizing ultrasonic fields is a convenient technique for a qualitative examination of transducer output and interaction of waves with complex objects. Partial quantification is possible using transparent color masks placed in the primary focal plane, and this approach is often referred to as “rainbow Schlieren”. A previously described folded path mirror-based system [Kaczkowski et al., J. Acoust. Soc. Am., 125,] has been enhanced to provide more detailed data by using narrowband spatial Fourier filters and automated acquisition of images by computer positioning of the mask. Pseudo-color encoding of the angular spectrum of the deflected light is now done after the complete sequence of narrowband images has been collected. The program also permits collecting sequences that vary transducer amplitude, frequency, or time delay between the ultrasonic pulse and the flash lamp strobe. Examples illustrating the utility of such a system for inspection of transducer arrays, rapid examination of different element phasing on emitted beams, and observation of the interaction of such beams with objects in the field will be presented. [Work supported by NIH CA109557 and EB007643.]
A miniature, ultrasonic transcutaneous energy transmission system for powering implantable medical devices.
Authors: Adamson R. B. A. , Bance M. , Brown J. A.
Published: October 2010

We present a novel miniaturized ultrasonic transcutaneous energy transmission system (TETS) for powering implantable hearing aids. To operate, implantable hearing aids typically require 50–80 mW of electrical power, which has traditionally been delivered through a set of coupled magnetic induction coils. Because of inherent trade-offs between size and efficiency in this design, typical devices are 50 mm diameter or larger which severely limits the implantation locations available to the surgeon, particularly when implanting infants. We have developed an ultrasonic TETS that offers comparable efficiency (>30%) to electromagnetic links in a device that, at less than 5 mm diameter, is more than an order of magnitude smaller. The ultrasonic TETS also shows a high degree of insensitivity to alignment and to separation distance of the transmit and receive transducers. We will present the results of measurements of electrical efficiency in experiments in water and tissue, and examine the theoretical limits on device efficiency and directions for improvement.
Specific absorption energy rate through a biological medium for an electromagnetic link crossing the skin.
Authors: Flores Martinez Joel , Becerra Garcia Jorge , Ramirez Rangel Patricia Lorena
Published: October 2010

The present paper describes the development of a radio-frequency electromagnetic field induced with a single pair of coils to transmit-receive a signal through the skin for a biological medium, with the purpose of obtaining data about efficiency and absorption to the transmission. In the future it is intended to energize an electronic circuit with this system, for a cochlear implant.
Acoustics pattern code to represent the contour of any visual image for people who are blind.
Authors: Martinez y Cardenas Jose Rodolfo , Menchaca Garcia Felipe Rolando , Berron Lara Virginia
Published: October 2010

In the search for rehabilitation for people who are partially blind through non-invasive means, an option is by the use of the ear. This paper proposes a conceptual prosthesis model called Acoustics-viewer. The idea is to generate acoustic patterns from contours representing optical images, from frequencies in the range of three octaves from a piano sound source.
Five valve compensating brass wind instrument.
Authors: Young Frederick J.
Published: October 2010

A companion paper shows how a triple brass instrument can be designed to yield a nearly perfect, well tempered intonation. This cannot be easily applied to the larger low-brass instruments because the inertia of triple valves increases as the square of the radius and varies with height. Double piston valves have been used for more than 130 years to change the pitch of large brass instruments. In May 2009, this author presented most of the known 3 and 4 valve systems including compensating ones. However well optimized, they are not in tune within plus or minus 5 cents. To solve this problem an instrument with four double valves and a tritone switch valve is presented and optimized to minimize the rms intonation error. The ratios of slide lengths to the instrument’s length are given by 0.126, 0.0631, 0.198, 0.337, and 0.413. The compensator slide ratios are 0.0522, 0.0261, 0.172, and 0.139. The instrument is to be tuned 3 cents sharp. Descending from the second open tone in semitones, the resulting errors in cents are 3.15, −2.97, −2.81, 2.65, 0, 0, 3.25, −2.97, −2.81, 2.65, 0, and 0. The rms intonation error is 2.37 cents, which is very acceptable in musical performance.
Design and construction of a bongo with sawdust and thermosetting polymer box.
Authors: Martínez Oscar D. , Rabadán Itzalá , Quezada Willebaldo
Published: October 2010

The body of the boat is made of polyester resin and sawdust. The study consists of the evaluation and comparison of the characteristics of the sounds emitted by a bongo with polymeric box and by a traditional bongo. This evaluation is achieved through the temporal evolution of sound through the waveforms, spectral analysis frequencies, and vibration modes of circular membranes. The results showed that for the polymer bongo, development times are shorter, and for the frequency spectra of sound from the bongos, as many harmonics are generated near the fundamental frequency on the bongos with wooden box, the modes of vibration in the membrane used in both cases of the bongos had a similar pattern, indicating that the proposed new building material meets the functional and acoustic characteristics of conventional materials. When using the polymeric box, the instrument does not lose its fundamental characteristics and harmonics; further, the harmonic content is enriched, giving a new structure in the body of the sound of the bongos with a comparison of the wooden box.
The National Polytechnic Institute carillon.
Authors: Cabrera Rodríguez Gustavo Eduardo , Beristain Sergio , Negrete Redondo José de Jesús
Published: October 2010

The bell is one of the oldest existing musical instruments, and due to mankind’s needs, it has been changing and adapting since the beginning. In the search for different types of communication, bell towers and carillons were created. Not only has the carillon survived until now, but it has also evolved thanks to several technological achievements, enjoying a unique place between all the musical instruments. On November 11, 2009, the “Plaza del Carillon” was inaugurated in the National Polytechnic Institute, in Mexico City; this event meant the rescue of a carillon donated by The Netherlands in the 1960s and, at the same time, a new opportunity for the people in the community to have a recreational place with lights, sculptures, and the sound produced by the carillon tower and its 48 bells. It is the purpose of this research to explain the way this carillon works and its principal features, gathering all the necessary information and measurements, besides the support of history and the existing documentation.
Music therapy and acoustic engineering: A first approach.
Authors: Arango Giraldo María Isabel
Published: October 2010

Five music therapy models which are accepted worldwide are studied in this work. It also includes three music therapies, which were chosen randomly, because they have research cases exposed to music. Professionals of different areas can easily study the global concepts of music therapy. It can be seen as a compilation of physiologic or psychological human effects and educational and work improvements of students or employees which were exposed to music therapy sessions. The results show changes in the client’s behavior to be analyzed statistically in the future; they can also be useful in future scientific researches. On the other hand, different definitions of common terms in several areas (medicine, neuropsychology, phone audiologists, music, music therapy and sound engineer) can be seen to minimize systematic mistakes when professionals communicate with one another. Finally, future lines of research are added to investigate the music therapy or other disciplines from the acoustic engineering point of view.
Vibration and noise issues in the oil and gas industry.
Authors: Rao Mohan D.
Published: October 2010

Vibration and noise issues are very prevalent in the oil and gas industry. Recently, work was halted for many days due to bad vibrations in the world’s largest floating platform used in the production of natural gas. The machines and equipment used for oil and gas production including transformers, engines, motors, generators, pumps, drill rigs, and piping generate very high levels of noise and vibrations that can cause downtime, occupational injuries, and noise induced hearing loss to workers. It is important to identify and solve these problems early by reducing the sources and paths of noise and vibration instead of afterthought band-aid type solutions or reliance on the use of hearing protection to protect the occupants. There have been many modern computational and experimental tools and techniques developed in the past two decades by the automotive and aerospace industries to solve a variety of noise and vibration problems. This presentation will highlight some of these tools and their applications to issues faced by the petroleum industry. Some case studies and examples using modal analysis, order tracking, noise path analysis, nearfield acoustic holography, finite element, and boundary element computational tools will be presented.