bluuebunny/crossref_metadata_2025 huggingface dataset:
Word extraction in adult-directed and infant-directed speech in African-American-English-learning infants
Authors: Katz-Gershon Shiri , Andruski Jean
Published: October 2013

Although there is evidence that infant-directed speech (IDS) facilitates word extraction in Standard-American-English (SAE)-learning infants, this effect has not been tested in African-American-English (AAE)-learning infants. An important question that remains unaddressed is whether infants are better tuned to word boundary cues in their native dialect than a non-native dialect. Specifically, do infants extract words more efficiently from IDS in their native dialect than from IDS in a non-native dialect. This study compares the ability of eight-month-old AAE-learning infants to extract words from AAE and SAE IDS. The head-turn preference procedure was used to measure infants’ memory for nonsense words embedded in sentences in AAE versus SAE. Infants were familiarized for 2 min with six sentences containing nonsense words and were then presented with both familiar and unfamiliar nonsense words carrying matching prosodic features. The difference in looking times between the familiar and unfamiliar nonsense words was used as a measure of word extraction. Results so far demonstrate an advantage of IDS over adult-directed speech in SAE. IDS in AAE is less advantageous than IDS in SAE. Acoustic analysis shows that the prosodic features of target nonsense words in SAE may make them more salient to infants than target words in the AAE sample.
The acoustic characteristics of infant cries
Authors: Yamane Naoto , Shimura Yoko
Published: October 2013

The present study measured the acoustic characteristics of infant cries. Twenty-eight infants participated, ranging from 2 to 23 months of age. Crying was elicited when their mother moved to a distance, leaving them in the lap of unknown person. The cries were recorded with a microphone placed 1 m from the infant’s mouth in an anechoic room. Analysis of the recorded cries revealed four patterns: cries were classified as either voiced or breathy, and as higher or lower than 7 kHz. Certain cry characteristics were later rated as more stress-causing, suggesting they could potentially elicit more abuse reactions. The recorded cries were presented to adults and breathy cries with a high-frequency component were labeled as emergency cries and as likely to cause high stress levels in parents and caregivers. In Japan, living spaces have recently begun changing such that environments are more echoic, perhaps exacerbating negative reactions to high-frequency components of infant cries.
Discovering place and manner features—What can be learned from acoustic and articulatory data?
Authors: Lin Ying , Mielke Jeff
Published: October 2013

Theories of phonological acquisition often assume that features are innate and universal, and establishing distinctive features requires the availability of minimal pairs. In this study, we explore an inductive approach to feature discovery without resorting to minimal pairs. Our basic assumption is that learners have access to a wide variety of phonetic information, and so feature induction can proceed through recursive clustering of the data. To test our hypothesis, we used as our data acoustic and articulatory measurements made simultaneously from a set of CVC syllables. The articulatory data are obtained with ultrasound imaging, and the vocal tract is characterized by a vector of cross distances from the tongue body to a reconstructed palate. The raw articulatory data are then mapped to a lower dimensional space using principle components, on which clustering is carried out. Experiments using acoustic and articulatory data suggest that these two sources of information lead to the discovery of place and manner features, respectively, thus bringing support to an alternative theory of feature learning.
Second-language speech perception: The modification of automatic selective perceptual routines
Authors: Strange Winifred
Published: October 2013

It is well established that late second language (L2) learners show significant difficulties in categorizing L2 consonants and vowels that do not occur in the native language (L1), or that occur, but differ in their phonetic realization in L1 and L2. These perceptual problems underlie (some) L2 production difficulties (accented L2 speech); lead to L2 comprehension difficulties, especially in nonoptimal listening environments; and may persist even after years of immersion in the L2 environment. However, it has been shown that intensive laboratory training (listening with feedback) can lead to improved perception of difficult non-native contrasts that: (a) generalizes to novel speakers and stimulus materials, (b) persists over months, and (c) produces improvements in production of trained segments. In the model presented here, changes with experience in patterns of phonetic perception are conceived of as reflecting the modification of language-specific (L1) selective-perceptual routines used to extract phonologically relevant information efficiently from continuous speech input. Theoretical and methodological issues will be discussed regarding (a) the conceptualization of (changes in) the structure of phonetic/phonological categories, (b) empirical assessment of phonetic perceptual learning, (c) operational definitions of mastery of L2 phonological categorization, and (d) implications for improving phonetic perceptual training techniques. [Work supported by NIDCD.]
Structural representation of the pronunciation and its application to computer-aided language learning
Authors: Minematsu Nobuaki
Published: October 2013

The conventional speech applications have been developed by looking at sound substances of speech and this strategy is derived from acoustic phonetics. However, the speech representation of this framework, e.g., spectrogram, is inevitably with nonlinguistic factors such as speakers and microphones. Then, all the developed systems come to select users, where the systems may work fine with a major part of the users but still work poorly with the others. The author believes that this situation should be avoided for educational applications because users don’t know whether they are outliers or not. Recently, the author proposed another framework of developing speech applications by looking at only sound contrasts and this strategy is derived from physically and mathematically interpreting structural phonology. On this new framework, nonlinguistic factors such as speakers and microphones are mathematically removed from speech as pitch information can be removed by smoothing the spectrogram. This talk shows what is possible by the new framework, which completely discards the absolute acoustic properties such as formants and spectral envelopes. In other words, in the new framework, an utterance is modeled as organized pattern of sounds although it has been modeled just as a linear string of sounds in the conventional framework.
Application of dynamic synapse neural networks on gunshot recognition
Authors: Dibazar Alireza A. , Park Hyung Ook , Yamada Walter M. , Berger Theodore W.
Published: October 2013

Identification of acoustic signals in noisy environments remains one of the most difficult of signal processing problems, and is a major obstacle to the high degree of accuracy and speed needed to identify suspicious sounds in high-security, high-safety environments. We have previously developed an acoustic recognition capability using a novel, biologically based Dynamic Synapse Neural Network (DSNN) technology. The DSNN-based technology has been demonstrated to classify target sounds with a high degree of accuracy, even in high noise conditions. In this paper we focus on extending the acoustic recognition capability of DSNNs to the problem of gunshot recognition. In order to recognize and localize the event, an array of four microphones is used for sound input. For localization purpose, time-delay estimation algorithm (TDE) is employed for triangulation. We have developed stand-alone, portable, and cost-efficient hardware with which both recognition and localization can be performed. In field-testing, the system classifies and localizes over 90% of the trained-for sounds. Performance for firecracker, starter pistol, 9-mm, and 44-caliber, explosion/firing sounds was also tested.
Environmental adaptation of hidden Markov models in an automatic sounds recognition system used for surveillance applications
Authors: Rabaoui Asma , Lachiri Zied , Ellouze Noureddine
Published: October 2013

Generally, the main goal of an automatic sound recognition system is to analyze in real time the sound environment of a habitat and to detect the abnormal sounds that could indicate a distress situation. In a surveillance application, the most encountered problem is the background noise that can be captured with the sounds to be identified. Thus, we propose to use a multistyle training system based on HMMs: one recognizer is trained on a database including different levels of background noises and is used as a universal recognizer for every environment. In order to enhance the system robustness, we will explore different adaptation algorithms that reduce the environmental variability. The algorithms closely examined are maximum likelihood linear regression (MLLR), maximum a posteriori (MAP), and the MAP/MLLR algorithm that combines MAP and MLLR. Experimental evaluation illustrates a recognition improvement over the baseline system (i.e., none adapted system) results. By using 156 adaptation scenes, the error rate of the adapted recognizer improves over the baseline system by more than 30% for rather all the considered algorithms, even under important noise degradation conditions.
Passive acoustic fiber Bragg grating sensor measurements of Green function in an instrumented part
Authors: Fisher Karl A. , Lehman Sean K. , Chambers David H.
Published: October 2013

The development of fiber Bragg grating (FBG) sensors for acoustic measurements permits the instrumentation of manufactured composite parts for the purposes of nondestructive evaluation (NDE) and lifetime monitoring. The parts can be designed from conception with an array of FBG acoustic receivers integrated into its internal structure for the purpose of multistatic data collection for NDE and monitoring of internal changes. The FBG array is accessed via a port on the outer surface and requires no additional power demands on the operation of the part. Data collection is accomplished by activating sources on the surface of the part and measuring the fields along the FBG array. We are particularly interested in Green function (GF) estimation of a FBG instrumented composite structure. By passively measuring diffuse acoustic fields throughout the volume, we use a technique developed by Lobkis and Weaver [J. Acoust. Soc. Am. 110(6), 3011–3017 (2001)] to estimate the GF within the part and monitor it over time. We describe FBG sensor array operation, review the theory of diffuse field GF estimation, and present examples in heterogeneous multilayered structures. [This work was performed under the auspices of the U.S. DOE by University of California Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.]
Super-resolution algorithms for ultrasonic nondestructive evaluation imagery
Authors: Clark Grace , Jackson Jessie
Published: October 2013

The spatio-temporal range resolution of ultrasonic measurements is often severely limited by the inherent band-limited spectral transfer function of ultrasonic transducers. This is manifested as ringing in the time domain. Super-resolution algorithms and a new MATLAB-based software system are presented for improving spatial resolution in one-dimensional (1-D) pulse-echo signals (A-scans). Two-dimensional (2-D) images (B-scans) and 3-D volumes are formed from suites of processed 1-D signals. The algorithms solve two inverse problems that are ill-posed and ill-conditioned. Regularization techniques and prior constraints are used to ensure useful results in practice. Given a noisy reflection signal (A-scan) u(t) and an associated reference signal x(t), the algorithms first solve the system identification problem to produce an optimal least-squares bandlimited estimate ĥ(t) of the impulse response of the material under test. Next, an algorithm based upon the method of alternating orthogonal projections produces a spectrum−extrapolated version ĥe(t) of the impulse response estimate. This estimate, when used in place of the raw reflection signal u(t), enhances the spatio−temporal resolution by mitigating the transducer distortion. The efficacy of the algorithms is demonstrated on real data from controlled experiments. Three different practical applications are presented, showing improved location of material interface boundaries. [Work supported by Grant UCRL−ABS−222494.]
Nondestructive technique to detect a crack in a concrete block by precise estimation of the surface wave
Authors: Murakami Takeshi , Fujioka Toyota , Nagata Yoshifumi , Abe Masato
Published: October 2013

This paper describes a method to estimate a crack’s position in a concrete block using several accelerometers. An array of accelerometers is attached to the concrete block and an impact is made on the concrete surface with a small hammer. If a crack exists, a reflection wave is generated at the crack position. Conventional methods to estimate the reflection point may seem to be useful for detection. Since the concrete block is elastic, however, it has three wave propagation modes: the surface wave mode, the primary wave mode, and the secondary wave mode. We cannot estimate the position using conventional methods because the necessary primary wave mode is weaker than the surface wave mode. To estimate the crack position precisely, we have already proposed two methods to eliminate the surface wave and side wall reflections. However, since the elimination is insufficient, they sometimes yield a peak at a position where there is no crack. Therefore, this paper proposes a method to estimate the surface wave more precisely to suppress such a peak. Some experiments were carried out, yielding better results.
Properties of focused time reversal operator in random media
Authors: Robert Jean-Luc , Fink Mathias
Published: October 2013

FDORT (focused DORT) is an alternative of the DORT method using focused transmits instead of single-element transmits. In the case of well-resolved point scatterers, the FDORT eigenvectors may be understood as invariants of the time reversal operator. However, if the medium is a collection of many subresolution scatterers (speckle), a different interpretation is more helpful. It is shown that, in speckle, the FDORT matrix may be interpreted statistically as a spatial correlation matrix, whose coefficients are the correlation between signals received by pairs of elements. The matrix is fully described by the Van Cittert Zernike theorem. The first eigenvector still has focusing properties, and the eigenvalues can be related to the so-called focusing criterion. Applications to aberration estimation in medical ultrasound are presented.
Multiuser communications using passive time reversal
Authors: Song Heechun , Hodgkiss William S. , Kuperman William A. , Akal Tuncay , Stevenson Mark
Published: October 2013

A recent paper [Song et al., IEEE J. Ocean. Eng. 31, 165–173 (2006)] demonstrated multipleinput/multiple-output (MIMO) multi user communications in shallow water using active time reversal where the time reversal array (i.e., base station) sent different messages to multiple users simultaneously over a common bandwidth channel. Passive time reversal essentially is equivalent to active time reversal with the communications link being in the opposite direction. This paper describes MIMO passive time reversal communications, which enables multiple users to send information simultaneously to the time reversal array. Experimental results at 3.5 kHz with a 1-kHz bandwidth demonstrate that as many as six users can transmit information over a 4-km range in 120-m-deep shallow water using QPSK modulation, achieving an aggregate data rate of 6 kbits/s. Moreover, the same data rate has been achieved at 20 km range by three users using 16-QAM modulation.
Concerning the sediment volume contribution to scattering in SAX04 (Sediment Acoustics Experiment 2004) sediment: Sound speed and bulk density fluctuations
Authors: Briggs Kevin
Published: October 2013

Sound speed and bulk density profiles measured from SAX04 sediment cores are used to estimate correlation lengths of fluctuations in the sound speed and the bulk density. Sound speed is measured from 5.9-cm-diameter cores at 1-cm intervals and bulk density is measured at 2-cm intervals from the same cores. Previous estimates of these parameters from experimental data involved fewer realizations (cores), limited sampling areas, and samples without mud flasers within the sand sediment. Values of correlation length may vary according to location within the SAX04 site. Correlation length values estimated with Burg’s algorithm from sediment sound-speed fluctuations averaged 2.24 cm, from sediment bulk density fluctuations averaged 2.53 cm. Ranges of values of correlation length estimated from bulk density fluctuations from locations inside the experiment site are used to present a range of volume scattering strength predictions, given the other parameters of sediment sound speed, sound attenuation, density ratio variance, and ratio of sound speed to density fluctuations used by the perturbation approximation to the composite roughness model for each location. At the SAX04 site, interface scattering dominated over volume scattering, despite the presence of mud inclusions with strong sound speed and bulk density contrasts. [Work sponsored by ONR.]
Measurement and modeling of elliptical particle motion in the seabed
Authors: Osler John C. , Chapman David M. F. , Hines Paul C. , Scrutton Jeffrey , Lyons Anthony P.
Published: October 2013

As part of the SAX04 experiment conducted off the coast of Florida in the Gulf of Mexico, four vector sensors containing three-axis accelerometers and pressure sensors were buried in the seabed. These served as the receivers to measure sediment sound-speed dispersion using a variety of techniques. One technique involved the generation of spherical waves from a point source in water and transmitted into the seabed in the frequency band 800 to 3000 Hz. In this geometry, the contribution of inhomogeneous waves to the field results in elliptical—rather than longitudinal—particle motion. The orientation of the elliptical orbit varies with the source-receiver geometry, frequency, and the sediment sound speed, thereby allowing measurements of sediment sound-speed dispersion. However, the orientation of the ellipse major axis is not always aligned with the direction of wave propagation suggested by Snell’s law. Measurements were made at several angles approaching the nominal critical angle in order to address the trade-off between increased sensitivity of the measurement versus greater departure from Snell’s law. Measurements and modeling of the elliptical particle motion are compared to ensure that the sediment sound-speed estimates account for any bias created by the inhomogeneous waves. [Work partially supported by ONR.]
Measurement of scattering wave from a buried object using an underwater vehicle
Authors: Tanaka Koichiro , Suto Taku , Fukai Takahiro
Published: October 2013

Measurements of a scattering wave from a buried object were carried out at a site in Tokyo Bay. The buried object was set below the bottom with about 10-m water depth. A crane suspended a subbottom profiler to insonify the object. In these measurements, the medium frequency (less than 10 kHz) was used to penetrate near the critical angle. Also, when the object shape is a cylinder and so on, the scattering wave appears strongly in the specific direction, which is with the shape of the object and the physical relationship of the source and the object. The direction where this scattering wave appears is strongly different from the source position, and it is difficult to catch in the mono-static position. Especially, because the level of the scattering wave becomes low in the case of the scattering from the object under the seafloor, it is favorable if the scattering wave can be measured in the direction with this strong level. Therefore, to catch this strong scattering wave, an underwater vehicle was used. A hydrophone array was attached at the head of the underwater vehicle to accumulate over a series of pings. This report deals with the way and results of these measurements.
Buried target detection with a synthetic aperture sonar
Authors: Piper John
Published: October 2013

During SAX04 the NSWC-PC dual-frequency synthetic aperture sonar collected data from a buried target field. Detections of a buried fluid-filled sphere from above critical angle averaged 34 dB and from below critical angle averaged 24 dB with a ripple field with predominant 42-cm spacing. These results are compared to simulated PCSWAT results.
Scattering of evanescent waves incident on targets in a simulated sediment
Authors: Osterhoudt Curtis F. , Marston Philip L.
Published: October 2013

When a sound beam in water is incident on a sediment at a sufficiently small grazing angle, the resulting wave field in the sediment is complicated, even for the case of flat, fluidlike sediments. The wave field in the sediment for a sound beam from a simple transducer has an evanescent component and diffractive components. This situation has been experimentally simulated by using a combination of previously described immiscible liquids [Osterhoudt et al., J. Acoust. Soc. Am. 117, 2483 (2005)]. Measured wave-field features are similar to those seen in a wave-number-integration-based synthesis (using OASES) for a related problem. Targets are placed in the evanescent wave field to simulate scattering by targets buried in marine sediments. Features of the observed backscattering are relevant to detecting and clarifying objects in sediments. Measurements include the resonant excitation of the organ-pipe mode of open water-filled cylinders previously studied with free-field illumination [Osterhoudt and Marston, J. Acoust. Soc. Am. 113, 2334 (2003)]. The degradation of the backscattering with increasing target depth and with target tilt were measured and modeled. Simple approximate models of these properties are facilitated by the localized coupling processes for the excitation of (and radiation by) organ-pipe modes. [Work supported by ONR.]
Observations of subcritical acoustic penetration of a sandy seafloor
Authors: Jackson Darrell R. , Hefner Brian T. , Williams Kevin L. , Thorsos Eric I.
Published: October 2013

During the sediment acoustic experiments, SAX99 and SAX04, buried hydrophone arrays were used in conjunction with sources mounted on a movable tower to study subcritical acoustic penetration. The seafloor at the SAX99 site displayed prominent, regular sand ripples of 48-cm wavelength. These caused downward diffraction of sound incident below the critical angle, resulting in elevated sound-pressure fields in the sediment. These measurements were made over the frequency range 11–50 kHz and were in substantial agreement with a first-order perturbation model. For SAX04, the frequency range was extended down to 2 kHz, but the site had weaker, more disorganized ripples. As expected, this resulted in weak acoustic penetration, with the pressure field primarily due to the evanescent wave. To further test the penetration model, artificial ripples of wavelength 50 and 75 cm were created by divers. These ripples increased sound penetration levels by 5–10 dB when the incidence azimuthal direction was normal to the ripple crests. The diffraction angles of the penetrating sound were found to be consistent with the predictions of the perturbation model. [Work supported by ONR.]
Backscattering from sediments: Comparison of scattering strengths from a simple sand and from a sand/mud environment
Authors: Williams Kevin , Thorsos Eric , Tang Dajun , Jackson Darrell
Published: October 2013

Two sediment acoustics experiments were carried out within 1 km of each other off the coast of Florida, the first in 1999 and the second in 2004. Though close in space the sediment was very different due to the effects of Hurricane Ivan in 2004. Hurricane Ivan resulted in the deposition of mud patches on top of the medium sand. Subsequent weather events deposited sand on top of these patches. The backscattering at each site will be presented for frequencies from 20 to 1000 kHz and grazing angles from 20 to 45 deg. At angles below the critical angle (30 deg) and frequencies below 150 kHz the backscattering measured in the two experiments is consistent given the difference in the sediment roughness spectra. Above the critical angle, however, the backscattering measured in the 2004 experiment is several dB higher than in the 1999 experiment and increases immediately above the critical angle instead of decreasing. This difference is attributed to an increase in sediment volume scattering in 2004. From 150 to 1000 kHz the data from both years indicate a change in scattering mechanism below the critical angle to a mechanism differing from sediment interface roughness scattering. [Work supported by ONR.]
Measurements of interface roughness and examination of near bottom interface properties
Authors: Tang Dajun , Hefner Brian , Williams Kevin , Thorsos Eric
Published: October 2013

A series of measurements was made of sediment properties during SAX04 over a 40-day period using IMP2, a sediment conductivity system; a stereo camera system made fine-scale interface roughness measurements toward the end of this period. During this period, several weather events (including Hurricane Ivan and a subsequent tropical storm) altered the sediment properties. The large, nonsymmetric ripples resulting from the hurricane decayed to a more symmetric form over time, while mud suspended in the water column was found first on top of the sand and then trapped just beneath the interface. Comparison of the interface roughness power spectra from IMP2 and the stereo camera shows good agreement at overlapping spatial scales and the stereo measurements extend the IMP2 estimation of the power spectra to a much higher spatial frequency. Complementary cores taken by a team from the Naval Research Laboratory at the same sites where IMP2 was deployed confirmed the depth and location of the imbedded mud found by IMP2. The implications of these environmental measurements to acoustic backscattering will be discussed. [Work supported by the ONR.]
Characterizing viscoelastic and anisotropic porous materials
Authors: Boeckx Laurens , Khurana Poonam , Vermeir Gerrit , Lauriks Walter , Desmet Wim
Published: October 2013

A wide range of commercial applications (building acoustics, food industry, automotive industry) can be found for porous materials. Accurate material characterization and modeling is vital for the use of these materials in multilayered systems due to increasing demands in acoustic comfort, noise legislation, and quality control during production. There is, however, a distressing lack in raw, accurate material data and measurement methods concerning the characterization of these materials. Measuring and modeling methods for the characterization of these materials will be presented. The experimental technique for the determination of the elastic properties is based upon the excitation of waveguides in porous materials. The other parameters of the Biot-Allard model are predicted using ultrasound. Acoustical properties can be predicted by using the measured structural material properties and incorporating them into a transfer-matrix-based multilayered model.
Linking microstructure and acoustic properties of open-cell foams
Authors: Perrot Camille , Panneton Raymond , Olny Xavier
Published: October 2013

A research program has been initiated in 2002 in order to link microstructure of high porosity open-cell foams to their acoustic properties. This paper is intended to highlight the main results of this study. The general objective of the research program is the determination of the acoustical macro-behavior from the physics at the local scale. A real rigid-framed porous media is studied. To this end, one needs first to determine the local geometry of the media, and second to solve over this geometry the partial differential equations that govern dissipation phenomena by thermal and viscous effects. The first step has been overcome by the technique of computed microtomography. This leads to experimental identification of the parameters of an idealized periodic unit-cell. The second step, solving harmonic heat and viscous fluid equations, is performed using Brownian motion and finite element simulations, respectively. Then, macroscopic behavior is obtained by spatial averaging of the local and frequency-dependent thermal and velocity fields. Results are presented in terms of two dynamic characteristic functions (viscous and thermal permeabilities) compared to impedance tube measurements. This computational methodology may be seen as a first step to optimize the microstructure of foams from a bottom-up approach for better sound proofing.
Interlaboratory experiments on the characterization of the acoustical and related nonacoustical properties of porous media
Authors: Horoshenkov Kirill , Khan Amir , Sgard Frank , Xavier Francois , Jaouen BecoLuc , Renault Amlie , Amirouche Nesrine , Hubelt Jorn , Pompoli Francesco , Prodi Nicola , Bonfiglio Paolo , Lauriks Walter , Boeckx Laurens , Pispola Giulio , Asdrubali Francesco , Atalla Noureddine , Amdin Celse , Gmerek K. Mark , Weston Adam
Published: October 2013

A series of reproducibility experiments on the characterization of acoustical parameters of selected samples of porous media is carried out on a range of porous samples in several independent laboratories in Europe and North America. The data on the characteristic acoustic impedance and complex propagation constant are presented in this work. In addition, the assessment of the related geometrical parameters required for modeling the acoustic performance of porous media, namely the steady-state flow resistivity, porosity, tortuosity, viscous and thermal characteristic lengths, and thermal permeability, is carried out. Detailed procedures related to sample preparation, and installation are discussed together with data on the material property variation observed between individual material samples and laboratories.
The effects of damped panels on sound transmission loss through lightweight framed construction
Authors: Tinianov Brandon
Published: October 2013

The incorporation of damping into the design of materials has been long understood as an effective method for improving the transmission loss of undamped, lightweight structures. Classic examples of its application include marine vessels, aircraft, and ground transportation such as trains, trucks, and buses. However, damping has rarely been incorporated into the materials used for the lightweight construction techniques found in modern buildings. This paper will review the basic principles of designing improved damping into construction materials using the well-known RKU model. The presentation will also review the mechanisms of energy transfer through lightweight building systems and present the improvements in acoustical performance due to damped materials. Typical gains are from 3–18 points in single number ratings (STC, Rw) and greater than 20 dB in some 1/3-octave bands. Extensive laboratory transmission loss data will be presented.
Resilient ceiling construction in residential buildings
Authors: Nash Anthony
Published: October 2013

In multifamily buildings, the floor/ceiling assembly between living units needs to be sound rated. In North America, a common light-frame floor construction involves wood or cold-formed metal joists spaced at 400 mm. The typical practice is to attach a gypsum board ceiling to the underside of the floor framing using narrow strips of ‘‘Z’’-shaped thin metal called ‘‘resilient channels.’’ If the resilient channels or the ceiling are installed incorrectly, the low-frequency sound insulation of the assembly can be seriously degraded. Based on our experience with resilient ceiling construction, there are two significant factors that have not yet been documented in an acoustical laboratory. One factor is to maintain a small separation around the entire perimeter of the ceiling where it intersects vertical wall surfaces (this void is later sealed airtight with a flexible caulking material). A second is the particular design of the Z-shaped resilient channel. The paper will discuss findings from two acoustical test series of floor/ceiling assemblies in wood-frame buildings. In both cases, the assembly was tested before and after modifications to the perimeter of the existing resilient ceiling. Each of the series also included tests of a complete ceiling reconstruction using an improved resilient channel design.
The effect of damping materials on heavy-weight floor impact in apartment buildings
Authors: Jeon Jin Yong , Yoo Seung Yup , Lee Pyoung Jik
Published: October 2013

Floating floors, in which resilient isolators are inserted between the structural slab and the upper layer of the floor, are generally used because of their effectiveness in controlling structure-borne and airborne noise. However, these isolators amplify low-frequency noises below 100 Hz that are generally produced by heavyweight impacts. Viscoelastic damping materials are widely used to reduce noise in settings such as vehicles, ships, and machinery; however, there has been no report of their use in apartment building structures for reducing floor impact sounds. The addition of damping can be embodied using viscoelastic liquid such as silicone gasoline; energy is absorbed with superior characteristics being a solid matter of viscoelastic materials. In this study, optimized thickness of the damping layer was investigated for the efficient reduction of low-frequency noise generated by heavy-weight floor impact. Effects of temperature variations on the characteristics of storage modulus and loss factor of the material were also investigated.
Comparative results of field impact isolation testing of numerous resilient underlayment systems for hard-surfaced flooring
Authors: Hale Marlund
Published: October 2013

There is a strong ongoing interest in replacing carpet and pad flooring in existing multi-family residences and during apartment conversions to condominiums with hard surface flooring. Installing such flooring often results in a significant decrease in the impact isolation performance of the floor/ceiling assembly. Some municipalities and/or homeowners associations have enacted regulations requiring that floor/ceiling assemblies meet specific minimum laboratory and/or field acoustical performance standards. This paper presents published vendor data and field performance test results for two condominiums in a multi-family residential complex for which both the city and the homeowners association have such performance requirements. A series of field tests was undertaken to assist the homeowners in selecting qualifying underlayment systems for their preferred hard surface flooring replacement of their existing quality carpet and pad flooring. The test flooring systems were each installed by a flooring contractor. All aspects of these field tests were maintained as identical as possible, with the only variable being the different commercial resilient underlayment products. Published vendor data of certified laboratory IIC test results are compared with the FIIC field test results.
Reflectivity of absorptive surfaces
Authors: Rathsam Jonathan , D’Antonio Peter
Published: October 2013

The random incidence absorption coefficient is a very coarse metric. In many small and large room applications, a directional absorption coefficient more accurately describes potential problems from first-bounce specular reflections. An impedance tube is useful for evaluating normal incidence absorption, but a more general approach to determining a material’s specular reflectivity or first-bound attenuation is needed. The AES-4id-2001 information document describes such a method. This study compares the ‘‘first-bounce specular attenuation’’ of 1 ft (H) ×3 ft (W) and 4 ft (H) ×8 ft (W) samples of 2-in.-thick, 6 pcf fiberglass absorbers (with and without fabric covering) with that of a rigid reflector, using a 2D boundary method goniometer. The boundary wave’s arrival is calculated and identified in the impulse response measurements. The use of small and large samples allows evaluation of both the fabric covering and boundary wave effects on the specular attenuation, for normal and 45-deg incidence. Time and frequency domain results are presented.
Acoustical design issues for contemporary places of worship
Authors: Duty Jason R. , Schwind David R.
Published: October 2013

This presentation intends to discuss the acoustical design of contemporary places of worship in the range of 500 to 3000 seats. The wide variety of programming requirements, concurrent uses, space constraints, and undesirable adjacencies in contemporary churches can be a similar challenge to many performing arts spaces. Many contemporary churches have loud, amplified music in their services and children’s classrooms. In addition, religious study courses in adjacent classrooms are being held at the same time as the main worship service. During off-hours the spaces are used concurrently for teaching, conferences, weddings, prayer, and rehearsals. In many cases, the rooms outside of the main worship space are undersized and have undesirable adjacencies to each other as well as the main worship space. Using case studies we will discuss sound isolation design to reduce interference between concurrent unrelated uses, as well as room shaping and room finish treatments (including variable acoustics) to address room acoustics and the large sound systems.
Alternatives to the traditional concert hall experience
Authors: Gibbs Bobby , Braasch Jonas , Krueger Ted
Published: October 2013

As relates to live performance, the purview of sound quality in architectural acoustics is mostly limited to concert halls. While the concert hall is perhaps the most common setting in which to hear live Western classical music in our present day, this was not always the case historically. As will be shown from analysis of published text as well as interviews with music critics, artists, and concert-goers, a variety of alternatives to the concert hall exists currently in the form of domestic settings, casual settings like coffee shops, as well as large outdoor settings like farms and parks. The advantages and disadvantages of such alternative venues, as concerns the overall concert experience and the quality metric of intimacy particularly, will be discussed. Moreover, design issues relating to the acoustical environment as well as the social environment in these venues will be discussed based on the data. This paper will ideally foster discussion in the acoustical and the architectural community on ways to expand the traditional concert hall experience as well as address design issues in alternative venues. [Work supported by ASA Minority Fellowship and RPI Humanities, Arts, Architecture, and Social Sciences Fellowship.]
New approach of the model experiment in room acoustics—advantage of 1/16 scale model
Authors: Shimoda Hidemaro , Tahara Yasuhiko
Published: October 2013

In the construction of the auditoria, the examination by the acoustic model experiment has been often performed. This paper describes the outline of the result of investigating various features of the method of the experiment by 1/16 scale models compared with models of 1/10 and 1/20 scales that have been generally adopted up to now. That is, the following advantages are found in the case study of the 1/16 scale model experiment, and the new approach to the model experiment method is proposed here. (1) full cover of the band to 4 kHz enables the quantification of a practical physical acoustic parameters. (2) The parameter as the air absorption coefficient in the supersonic wave band by 1/10 scale models can be used. (3) Cheap digital sound recording system can be used considering the microphone characteristics. (4) The model construction cost can be largely saved compared with 1/10 models.
Considering source directivity in a recital hall with seats surrounding the platform
Authors: Lin Wei , Chiang Weihwa , Chen Yi-run
Published: October 2013

The impact of source directivity can be significant for chamber music performances, in particular for arena-type halls that have visual intimacy. This study has been carried out to understand the physical and perceptual aspects of the seats surrounding the platform in recital halls. Effects of architectural features were evaluated using computer simulations that accounted for source directivity and diffusive reflections. Both live and recorded subjective evaluations of chamber music performances were made in an actual hall while acoustical measurements were also taken. As a result, computer simulations using a singer source showed significant decrease in both clarity and strength in the 2-kHz band for the seats surrounding a centered platform. A wall 6 m in front of the platform was effective in mitigating the problems. Sound levels calculated from the recordings taken from various viewing angles were correlated with subjective evaluations, especially in the high frequencies. Timbre appeared to be the principal factor influencing solo performances and balance was the most important in judging ensembles. Nevertheless, live evaluation showed no significant difference among the listening positions.
Wild dugongs’ vocal responses to conspecific calls
Authors: Ichikawa Kotaro , Arai Nobuaki , Akamatsu Tomonari , Shinke Tomio , Adulyanukosol Kanjana
Published: October 2013

Wild dugongs were found to call back more to conspecific calls than to artificially synthesized sounds. The population was exposed to four different playback stimulii a wild dugong chirp, a synthesized down-sweep sound similar to the dugong chirp, a synthesized constant-frequency sound, and no sound as a control. Vocalizing dugongs were localized using an array of stereo-underwater-recording systems. Wild dugongs vocalized more frequently after the playback of dugong chirps (2.8 calls/min) than those of constant-frequency (0.55 calls/min) and control (0.2 calls/min), (p>0.01, Kruskal-Wallis test). Dominant frequencies of response calls were 4810 Hz to dugong chirps and 4470 Hz to down-sweep sounds. These were higher than those to other stimuli (3794 and 4044 Hz). Distances of calling-back dugongs from the playback speaker were significantly shorter for dugong chirps (10.19 m) and down-sweep (19.02 m) than that for constant frequency (105.84 m) (p>0.001). The observed dominant frequencies of response calls (4510 Hz) were above the cutoff frequency of Lloyd’s mirror effect in shallow waters of the present study. Frequency-modulated narrow-band sounds like chirps travel longer and enable accurate measurements of source directions by binaural receivers. These suggest that chirps could be used for conspecific recognition in noisy acoustic scenes in tropical shallow waters.
How does a green leafhopper male induce a female’s willingness to mate?
Authors: Fukui Masao
Published: October 2013

When on their host plants, male leafhopper Nephotettix nigropictus (Insecta; Hemiptera) produces substrate-borne signals of two kinds, which are associated with different behavioral activities: (i) a calling signal and (ii) a duetting signal in response to a female. These signals both influence pair formation and the female’s willingness to mate. After receiving a vibrational reply from a female responding to the calling signal, the calling male increases the first component of the calling signal from one trill to two or more trills, then continues in a duet with the female. During more duets, males wanting females to mate increase the number of chirps that compose a buzz as the second component of the calling signal. This increment of the first component is almost always one stable trill, but the increment of the second component apparently depends on the strength of the female’s reply. This paper presents discussion of the biological significance and role of male signals to induce females to mate.
An avian cocktail party: Masking and unmasking in birds
Authors: Dent Micheal , McClaine Elizabeth , Shinn-Cunningham Barbara , Best Virginia , Ozmeral Erol , Gallun Frederick , Sen Kamal , Narayan Rajiv
Published: October 2013

The ability to effectively communicate in a noisy environment is an auditory skin that all animals must develop for basic survival. Birds are one group of animals that use auditory communication for everything from mating to prey capture. In general, how well humans and other animals are able to hear signals in their environment is a function of the properties of the signal and the properties of the noise, and include spatial, temporal, and spectral characteristics. Here, the abilities of birds to correctly identify zebra finch songs embedded in different types of maskers that were emitted from the same location or from separate locations (and presented at different signal to noise ratios) were measured using operant conditioning techniques. In general, zebra finches and budgerigars showed very small differences in thresholds between songs embedded in the three types of maskers: broadband noise, modulated noise, and choruses of zebra finch songs. When the calls were emitted from one location and the maskers from another, a condition that elicits spatial unmasking in humans (Best et al., 2005), zebra finches had lower thresholds while budgerigars generally did not. These results suggest some species-specific advantages to listening in noisy environments.
Assessing the relative importance of source distance determined by acoustic cues and noise level as predictors of disturbance in a study of the Mexican spotted owl
Authors: Bowles Ann E. , Moffat Stefanie K. , Denes Samuel L. , Hobbs Christopher M. , Banwart Dana H.
Published: October 2013

In forested areas, acoustic localization of source distance and noise level are potentially reliable indicators of an approaching source. The relative importance of these cues was examined during a study of Mexican spotted owl responses to human-made noise. The study was conducted in mixed-conifer forest on steep northeast facing slopes. Owls had no or limited experience with the experimental paradigm. Shaped noise bursts were projected from a Sound Projections portable stereo speaker system with line of sight to the target owl(s). Signals were shaped noise bursts with 10–15-dB/s onset rate projected to produce received maximum A-weighted levels in two ranges, 55–65 dB and 75–85 dB, at distances of 20, 40, and 80 m. Levels were measured a short distance from the target owl(s) using a calibrated recording system (DAT or digital recorder equipped with an ACO 7013 microphone, 20 Hz to 20 kHz). They were also estimated using a single-event sound propagation model (NMSIM,Wyle Laboratories). Preliminary analysis showed that both source level and distance were significantly related to owl response, but that distance explained twice as much variance in behavior as level. [Work supported by ACC/CEVP; USFWS Permit No. TE024429.]