bluuebunny/crossref_metadata_2025 huggingface dataset:
Eigenvalue equalization applied to the active minimization of energy density in a mock helicopter cabin
Authors: Lovstedt Stephan P. , Thomas Jared , Sommerfeldt Scott D. , Blotter Jonathan
Published: October 2013

A number of applications in active noise control require the ability to control and track multiple frequencies. If a standard filtered-x algorithm is used, the system must be designed to be stable for the slowest converging frequency anticipated, thereby leading to reduced overall performance of the system. Previous work has focused on overcoming this through development of a method that equalizes the eigenvalues of the system over the operating frequency range, leading to more uniform performance. The current work has built on the previous work to extend the method for implementation in systems that control the acoustic energy density. Minimizing energy density has been shown to have favorable performance characteristics when used for controlling enclosed acoustic fields. Thus, combining the approach of equalizing the system eigenvalues with energy density control leads to a system that incorporates the advantages of both methods. The control approach is demonstrated through implementation in a mock helicopter cabin, to demonstrate the favorable convergence characteristics, along with the global control of the field.
Active noise reduction communication earplug for helicopter crew
Authors: Solbeck Jason A. , Maher Matthew , Deitrich Toby , Ray Laura R. , Collier Robert D.
Published: October 2013

A custom designed shallow insert communication earplug for helicopter crews consists of a system based on a patented hybrid ANR feedback-feedforward algorithm [Ray et al., J. Acoust. Soc. Am. 120(4), 2026–2038 (2006)]. The hybrid system provides the benefits of feedback ANR while extending the bandwidth and magnitude of total ANR performance with feedforward ANR, which improves attenuation of tonals. The development includes optimized algorithms, a custom earplug, and a miniaturized battery powered ANR module, weighing approximately 250 g. The hybrid ANR earplug requires two miniature microphones, one inside and one external to the earplug and an internal speaker to deliver the cancellation signal. The software automatically adapts the ANR algorithm to the transfer function characteristics of the system to both improve performance and accommodate individual human fitting differences. The testing protocol and results are based primarily on measurements with a HEAD Acoustics manikin in the Sound Innovations sound room [Duncan et al., Proceedings of Internoise 2006, December 2006]. MIRE testing is planned for the Spring of 2007. Results to-date demonstrate comparable passive attenuation to a commercially available communication earplug and an added average active attenuation of approximately 6 dB for UH-60 helicopter noise. [Work supported by U.S. Army.]
NASA-sponsored active fan noise control research
Authors: Posey Joe , Jones Michael
Published: October 2013

The National Aeronautics and Space Administration (NASA) has espoused the vision of developing technology capable of keeping all objectionable aircraft noise within airport boundaries. In order to achieve such an aggressive goal, new aircraft will have to be designed employing quiet propulsion, quiet lift, and quiet drag. Research activities are continuing on all these fronts. Dominant sources of propulsion noise to date on jet-powered transports have been jet noise and fan noise. As bypass ratios of aircraft turbofan engines have increased to improve fuel efficiency, jet velocities (and therefore jet noise) have decreased, making fan noise the larger contributor in many instances. In NASAs Advanced Subsonic Technology (AST) Program, which ran from 1994 until 2001, several active control strategies for tonal fan noise were investigated. These included rings of wall-mounted actuators, active impedance control, stator-mounted actuators, and hybrid active/passive concepts. The most promising approach seems to be stator-mounted actuators to provide control sources effectively co-located with the rotor/stator interaction source. The major remaining issue for active control of fan tones is the availability of high-powered, compact, efficient actuators for stator mounting. Control of broadband fan noise has been addressed, but much work remains to be done.
Effects of liquid compressibility on coupled radial and translational motion of a bubble
Authors: Hay Todd A. , Hamilton Mark F. , Ilinskii Yurii A. , Zabolotskaya Evgenia A.
Published: October 2013

In shock wave lithotripsy, explosive bubble growth is followed by a collapse phase during which bubble wall velocities can approach the speed of sound in the liquid. If the bubble is simultaneously in translation, the velocity of translation can also exhibit a very large spike during rebound. The velocity spike corresponds to conservation of translational momentum as the bubble radius, and thus entrained mass, become very small. It can then be important to include effects of compressibility on both the radial and translational motion. This presentation discusses corrections to the coupled equations for radial and translational motion when compressibility, and therefore acoustic radiation, are taken into account. For pure radial motion, compressibility introduces a radiation term proportional to the third time derivative of bubble volume, and inversely proportional to sound speed. For pure dipole motion, linear theory predicts a radiation force proportional to the second time derivative of the translational velocity, also inversely proportional to sound speed [Morse and Ingard, Theoretical Acoustics (1968)]. Numerical simulations will be presented that illustrate the magnitudes of compressibility effects on solutions of the coupled equations for radial and translational motion. [Work supported by the NSF Graduate Research Fellowship.]
Nonlinear shear wave beams
Authors: Wochner Mark S. , Hamilton Mark F. , Zabolotskaya Evgenia A.
Published: October 2013

The theoretical framework developed previously for plane nonlinear shear waves [Zabolotskaya et al., J. Acoust. Soc. Am. 116, 2807–2813 (2004)] has been extended to include diffracting beams. Two coupled KZK-type equations with cubic nonlinearity are obtained for the two transverse components of the particle velocity vector. The coupled nonlinear equations are solved numerically in the time domain using a nonoscillatory numerical scheme. Both linearly and elliptically polarized beams are considered. For circular polarization the equations decouple and become linear. Waveforms along the beam axis are presented that illustrate shock formation and coupling of the two velocity components for different polarizations. Beam patterns are presented showing the angular dependence of the nonlinearly generated harmonics. Because the evolution equations are derived using the parabolic approximation for narrow beams, the predicted beam patterns are axially symmetric for all polarizations whenever the amplitude and phase of the source are axially symmetric. Comparisons are made with the corresponding results obtained from the quadratically nonlinear KZK equation for sound beams in fluids. [Work supported by NIH and ARL IR&D.]
Leaky Rayleigh waves propagating around the corner of a thick solid plate: Finite element analysis
Authors: Lamkanfi Ebrahim , Declercq Nico F. , Van Paepegem Wim , Degrieck Joris
Published: October 2013

Finite element simulations reveal the experimentally indicated fact [Declercq et al, J. Appl. Phys. 96(10), 5836–5840 (2004)] that leaky Rayleigh waves propagating along the horizontal surface of a thick fluid-loaded solid plate are transmitted around the corner of the solid plate. The experiments indicate that leaky Rayleigh waves are generated around the corner of the plate, but the experimental evidence is not fully conclusive whether the effect is caused merely by incident Rayleigh waves on the upper surface or by scattering effects when the incident beam interacts with the corner. The current study first investigates the reported experiments by means of the finite element method. Then the model is applied to study leaky Rayleigh waves separately from the incident and reflected bounded beams. It is shown that the Rayleigh waves themselves are the physical origin of the transmission of Rayleigh waves and not the scattering effects caused by the incident bounded beam interacting with the edge of the plate.
Multiple scattering by a random configuration of cylinders in a poro-elastic medium: Properties of the coherent waves
Authors: Luppé Francine , Conoir Jean-Marc , Robert Sébastien
Published: October 2013

An extension of Twersky’s formalism is developed in order to obtain the dispersion equation of the coherent waves in a poro-elastic medium in which cylindrical scatterers are randomly placed. The high frequency regime only, where no dispersion effects occur in the absence of scatterers, is investigated. The scatterers lay within a slab-like region of the host medium, and an incident harmonic plane wave gives rise to coherent plane waves in the slab. At normal incidence, the coherent waves are damped, while they are inhomogeneous at other incidence angles. The dispersion equation obtained shows that the longitudinal (fast and slow) coherent waves are coupled, while the shear one obeys the Waterman and Truell’s well-known dispersion equation.
Practical kurtosis-based blind recovery of a speech source in real-world noise
Authors: Kleffner Matthew D. , Jones Douglas L.
Published: October 2013

In many multi-sensor, single-source applications noise interferes with cleanly recovering the source. Various approaches have been designed to recover sources in interference, but most of them require prior knowledge or assumptions that limit their applicability to real-world environments. We present a novel and practical frequency-domain method for blindly recovering a single, nonstationary, high-kurtosis source in arbitrary low-kurtosis interference using a narrowband kurtosis objective. This method handles convolutional mixing, does not impose a theoretical limit on the number of interferers, and relies only on the kurtosis properties of the source and interference. A kurtosis-based objective is used to compute instantaneous filter weights in each frequency bin, since linear combinations of speech with low-kurtosis interference tend to have lower kurtosis than speech alone. The set of bin-by-bin scale factors needed for the total spatio-temporal recovery filter are computed by using estimated steering vectors to recover the signal as it would sound at a particular sensor. Speech signal-to-interference ratio gains of 5 to 10 dB are demonstrated at low input SIRs in a variety of real-world situations in both a car and a reverberant room.
A correlation feedback model of audio-visual integration
Authors: Luu Sheena , Wong Willy
Published: October 2013

To date, a lot of empirical research has been done by many laboratories to investigate how information from different senses interacts to affect perceptual experience. Given the quantity and variety of observations published, it is necessary to begin to organize and integrate the information into a coherent framework. Here a framework is presented in the form of a systems-level model of auditory-visual interaction in the brain. The temporal correlation feedback model is a computational model to illustrate the change in human experience and perception of auditory and visual information as a result of the interaction of the two senses. The model is able to explain many of the effects of audiovisual integration and the characteristics of audiovisual synchrony detection observed in other studies.
Spectral coherence predicts perceptual resilience of speech to temporal distortion
Authors: Stilp Christian E. , Alexander Joshua M. , Kluender Keith R.
Published: October 2013

Speech perception is remarkably resilient to signal perturbation. For example, Saberi and Perrott [Nature, 398, 760 (1999)] found that sentences in which successive segments as long as 130 ms have been temporally reversed are relatively intelligible. They suggested that ultra-low-frequency modulation envelopes (3–8 Hz) are critical to intelligibility. We tested whether information transmitted, not physical units (e.g., ms, Hz), better explains performance. Listeners heard a large cohort of synthesized, seven-syllable sentences at three different speaking rates (2.5, 5.0, 10 syllables/second) with time-reversed segments of multiple durations (20, 40, 80, 160 ms). Intelligibility decreased as duration of time-reversed segments increased, decreasing more slowly for slower (longer) sentences. When intelligibility is plotted to reflect proportion of message (not time) that was time reversed, data for all three rates collapse onto a single curve. To estimate potential information across time, we used spectral coherence to quantify the degree to which successive portions of the signal are similar to, or can be predicted from, a given spectral slice with no prior expectations such as knowledge of speech or language. Spectral coherence alone accounts substantially for performance. Information transmission, not physical measures of time or frequency, is more useful for understanding perception of speech. [Work supported by NIDCD.]
Transformation of live versus recorded speech from the mouth to the open or occluded ear
Authors: Barac-Cikoja Dragana , Kozma-Spytek Linda , Adamovich Stephanie
Published: October 2013

Auditory self-monitoring studies require the participants’ speech feedback to be manipulated experimentally and then presented to the ear. The acoustic levels of the altered speech must be the same as those under normal speech feedback conditions when speech is transmitted to the ear live, directly from the mouth. Therefore, it is critical to understand the transfer function between the mouth and the eardrum. To further this understanding, live and played-back self-generated speech for two female and two male individuals were recorded using a probe tube microphone inserted into the ear canal at a fixed distance from the tragus. The played-back speech samples were delivered via a B&K artificial mouth, at the sound pressure level calibrated to match the level at the lips. The artificial mouth was placed offset to the participants right side and in line with the x and z axes of his/her mouth position. Recordings were conducted with the ears either open or sealed with ER-3A insert earphones. In addition, the level and content of speech were systematically varied. The equivalent sound level and long-term average spectra of the corresponding pairs of speech samples were analyzed as a function of the experimental manipulations.
Acoustics of music and voice in Jewish worship spaces
Authors: Kleiner Mendel , Klepper David , Orot Yeshivat Beit
Published: October 2013

Of the three monotheistic faiths, Judaism is the oldest, and one would expect synagogue architecture to predate mosque and church architecture. In fact, that is the case. The earlier synagogues actually were constructed while the Second Temple remained as the focal point for Jewish prayer, because local shrines and study halls developed during this period. Excavations indicate general simple rectangular halls of worship. Synagogue architecture developed in several styles and, of course, was influenced by both mosque and church architecture. The latter has been particularly true with non-Orthodox synagogues in Western countries, some of which have high-quality pipe organs and face the speech vs. music issue also faced by main-stream Protestant and Catholic churches. Meanwhile, Orthodox synagogues have become larger, and some Orthodox Rabbinic authorities have approved single-sided amplification, with current varied but without zero crossings. The most recent development in sound system technology, steerable pattern line sources, have presented the possibility of new and superior solutions to sound amplification in the worship spaces of all three faiths, supplementing the past solutions of central directional-horn-based systems, distributed systems of various types including pew-back, and delayed column loudspeakers, which may still have applications in some situations.
Voicing and silence periods in daily and weekly vocalizations of teachers
Authors: Titze Ingo , Hunter Eric , Vec Jan
Published: October 2013

The National Center for Voice and Speech data bank on voice dosimetry was used to study the distributions of continuous voicing periods and silence periods in 31 teachers over the duration of two weeks. Recordings were made during all awake hours of the day. Voicing periods were grouped into half-decades, ranging from 0.0316 0.10 s for the shortest periods of phonation to 31.6 100 s for the longest periods of phonation. Silence periods were grouped into similar half-decades, but ranged up to periods of several hours. On average, the teachers had 1,800 occurrences of voicing (onset followed by offset) per hour at work and 1,200 occurrences per hour while not at work. Voicing occurred 23% of the total time at work, dropping to 13% during off-work hours and 12% on weekends. The greatest accumulation of voicing occurred in the 0.316 1.0 s voicing periods, whereas the greatest accumulation of silence occurred in the 3 10 s silence periods. The study begins to lay the groundwork for understanding vocal fatigue in terms of repetitive motion and collision of tissue, as well as recovery from such mechanical stress.
Balancing reflection strength and loudness in small concert halls.
Authors: Gulsrud Tim
Published: October 2013

Small concert halls, such as those encountered at many music education institutions, are frequently called upon to support a wide range of musical ensembles, including full symphony orchestra, within a volume significantly smaller than in traditional concert halls. On one hand, a degree of early reflection strength and reverberation is needed to support unamplified instruments and musician hearing on stage. On the other hand, constrained cubic volumes, limited audience seating, and sound-reflective finishes can lead to overloudness in these small halls. This paper will discuss recent listening and measurement experiences in small concert halls as they relate to achieving a suitable balance between reflection strength and loudness control.
Case studies of variable acoustic design: A repertory theater and performing arts chapel.
Authors: Conant David
Published: October 2013

Two multipurpose halls required variable acoustic design with minimal alteration of their appearance. The 400-seat Performing Arts Chapel at Fuller Theological Seminary (awaiting construction) will accommodate everything from pipe organ concerts to lectures-in-the-round by employing multiple variable acoustics methods with adjustable treatments deployed above the visual ceiling and along sidewalls and the performance platform. The 550-seat Virginia Piper Theater at the Mesa Arts Center (recently opened) successfully hosts everything from drama to choral works via novel, inexpensive, and wonderfully simple means, entirely beyond audience view.
A dynamic approach to attending: New issues.
Authors: Jones Mari Riess
Published: October 2013

Musical events entail crafted serial changes in frequency, intensity, and time that are explicitly patterned to engage attending activities over relatively long periods of time (i.e., versus brief time periods required for single tones). Serial changes vary in salience, with some functioning as accents outlining higher-order time spans between nonadjacent tones. Accordingly, attending to music must be dynamic and sustained, capable of anticipatory behaviors while continuously reacting and adapting to various serial changes, accented and unaccented. Issues of meter perception and melodic phrasing also mean that attending must be responsive to different time levels marked by accents. Approaches to attending that ground attentional tracking in biological entrainment have potential for describing these aspects of musical listening. They also raise new issues, as illustrated in experiments inspired by entrainment theories; as reviewed here, these address effects of rhythm on time discrimination, time judgments, and responses to melodic changes. Also considered are general issues relating to development of new paradigms, age-specific preferred rate (i.e., preferred intrinsic periods), and synchronization limits.
Tempo fluctuation and predictive synchrony in music.
Authors: Rankin Summer , Large Edward , Fink Philip
Published: October 2013

The goal of this study was to understand the ability of musicians and nonmusicians to entrain to musical performances with naturally fluctuating tempo. In experiment 1, we investigated the nature of tempo fluctuations produced by a musician. We collected four music performances from a skilled pianist who was instructed to play with natural expression. We extrapolated the beat times by comparing the performances with the musical scores and performed a spectral analysis and a rescaled range analysis on the interbeat intervals. The results indicate fractal scaling of the performance tempo in each case. Thus, musical tempo fluctuations exhibit long-range correlations characterized by a 1/f type long memory process. The stimuli in experiment 2 included two performances from experiment 1 and mechanical versions of the same pieces. Participants were asked to synchronize at slower (quarter note) and faster (eighth note) metrical levels. Musicians and nonmusicians synchronized successfully and were able to accommodate large tempo fluctuations. Entrainment was superior at the slower metrical level. Participants were less variable for the mechanical versions. Most importantly, participants predicted the tempo fluctuations observed in experiment 1, suggesting a possible relationship between fractal tempo scaling, pulse synchronization, and neural oscillation in the perception of rhythm. [Work supported by NSF grant BCS-0094229.]
Underwater acoustic scene analysis: Exploration of appropriate metrics.
Authors: Ellison William T. , Frankel Adam S. , Zeddies David , Vigness Raposa Kathleen J. , Schroeder Cheryl
Published: October 2013

A recent review of published accounts of acoustic noise exposure and behavioral response found that the reported results were often limited by the lack of supporting information on basic acoustical metrics as well as potentially important contextual variables. [Southall et al., Aquat. Mamm. 33, 411–521(2007)]. Human studies have also shown that simple measures such as sound level are insufficient to represent complex acoustic scenes [Dubois, J. Acoust. Soc. Am. 122, 3011–(2007)]. While source and received levels are frequently reported for underwater studies, other characteristics of the resultant acoustic field are rarely described. Understanding the full spatial, temporal, and spectral nature of the sound field can provide additional quantitative measures useful in elucidating the animals’ response to the incident sound field exposure. The animals’ perception of received acoustic field may also be influenced by the biological meaningfulness of the signal and the experience of the receiver with signals of a given type. Here we provide guidelines for future studies corresponding to three phases: preplanning, field measurements, and postmeasurement analysis, addressing acoustic field metrics as well as the seasonal distribution and baseline behavior of the animals of interest. Examples from selected field measurements will be used to illustrate the salient features.
Is it time to seriously consider the effects of acoustic particle motion on hearing and behavior in fish?
Authors: Hastings Mardi
Published: October 2013

Although sound exposure level (SEL) and sound pressure level (SPL) are the metrics being applied to assess effects of underwater sound on fish, no correlation exists between SEL or SPL and temporary threshold shift (TTS) or behavior. Certainly particle motion plays a major role in the auditory scene of fishes because their inner ears are literally accelerometers that detect signals via relative motion between sensory epithelia and solid otoliths in the auditory endorgans. Most all hearing data, however, continue to be measured with respect to SPL, and TTS with respect to SEL or SPL. Neither metric accounts for effects of particle motion. An analysis of findings from several recent acoustic impact studies on various species using different types of sources indicates that differences in observed effects are most likely due to differences in received levels of acoustic particle motion. Field studies with real sources in open water predict an onset of TTS at higher SEL than do studies conducted in confined spaces or with specimens located in the source near a field where acoustic particle motion is higher than estimated by simple pressure–particle velocity relationships. Thus monitoring only sound pressure may not be sufficient to protect fish from adverse impacts.
Measuring the impact of native inventory and native contrast on vowel perception.
Authors: Ettlinger Marc , Johnson Keith
Published: October 2013

Theories of speech perception differ as to whether experience with sounds or with sound contrasts is more important when discriminating novel sounds. To explore this question, 21 American English, 16 Turkish, and 16 French speakers were tested on their ability to discriminate high front vowels in German (/i/,/y/,/Y/,/I/). The crucial difference between the languages is that English only uses the tense-lax contrast (/i/-/I/), while Turkish and French only use the rounding contrast (/i/-/y/). If contrast is crucial, then English speakers should be better at discriminating /y/-/Y/, whereas if the inventory is crucial, then they should be better at discriminating /I/-/Y/. The results of a fixed discrimination task show that there is no significant effect of language and that the tense-lax contrast (/i/-/I/; /y/-/Y/) is universally more easily discriminated than the rounding contrast (/i/-/y/; /I/-/Y/). The results of a rating task do reflect an influence of language, however, with English-listeners rating /I/-/Y/ as more distinct and French and Turkish speakers rating /y/-/Y/ as more distinct. So, because English has /I/, but no rounding contrast, what matters in the perception of new sounds is not experience with contrasts, but rather experience with particular sounds.
Dialectal differences in dynamic formant patterns in vowels.
Authors: Fox Robert Allen , Jacewicz Ewa
Published: October 2013

This study examines basic acoustic variation in the dynamic patterns of vowel formants among three regional variants of American English spoken in southeastern Wisconsin (affected by the Northern Cities Shift), western North Carolina (Appalachian English affected by the Southern Vowel Shift), and central Ohio (not considered to be affected currently by any vowel shift). Three groups of speakers (including men and women) produced vowels in citation form (in a /hVd/ context) and in sentences. The sentence material elicited two degrees of vowel emphasis (high and low) in the /bVd/ and /bVt/ contexts. The frequencies and amplitudes of the first three formants were extracted at points corresponding to 20%-35%-50%-65%-80% of the vowel’s duration. A set of dynamic measures was then calculated using these values that included overall signed/unsigned change in formant frequencies, vector and trajectory lengths, direction/angle of vowel movement in the F1 by F2 plane, and rate of frequency change. The results show significant cross-dialectal differences in formant patterns in monophthongs, phonemic diphthongs, and nonphonemic diphthongs. The nature and extent of these formant changes varied as a function of speaker dialect in a manner apart from expected variation resulting from phonetic and prosodic context and speaking style. [Work supported by NIH.]
Production and perception of two vowels in Northeast Ohio.
Authors: Schmidt Anna , Powell Lois
Published: October 2013

In Northeast Ohio, three dialect regions converge: the Inland North, North Midland, and Pittsburg regions (Labov et al. 2005). It is believed that the vowel in “bat” is raising and fronting while the vowel in “bet” is lowering and backing as part of the Northern cities vowel shift in the Inland North region. Earlier data from 50 talkers (aged 18–25) from these regions suggest vowel movement in each region with a full merger or reversal of the two vowels only for Inland North talkers. Talkers from all regions produced longer bat vowels than bet vowels. The current study examined perception as well as production of the vowels by talkers from these regions. Participants heard two synthetic vowel continua and identified the vowels: a duration continuum, in which the formant pattern was constant but the vowel duration varied, and a formant continuum, in which the duration was constant but the formant pattern varied from a low backed vowel to a high fronted vowel. Perception patterns were compared to production patterns in order to determine if (a) longer vowels were identified as bat vowels and (b) vowel identification followed vowel production.
Perception of Japanese mora nasal /N/ and mora obstruent /Q/ by native Japanese, English, and Thai speakers.
Authors: Nozawa Takeshi , Furukawa Yuriko
Published: October 2013

Japanese mora nasal /N/ and more obstruent /Q/ are produced at different places of articulation, being homorganic with the following consonant. Four native speakers of Japanese produced /N/ and /Q/ in /CVNCV/ and /CVQCV/ contexts, where the consonant after /N/ and /Q/ is always a stop. Their utterances were recorded and digitized. The word final /CV/ was edited out, and the stimuli with the structure of /CVN/ and /CVQ/ were created. Twelve native speakers of Japanese, American English, and Thai were recruited as listeners. The listeners were told to identify the syllable-final nasal (/m/, /n/ or /ŋ/, and the missing stop (/p/, /t/, /k/, /b/, /d/, or /g/). Generally, the Thai listeners outperformed the other two groups of listeners, and the Japanese listeners performed most poorly. The Thai listeners good performance may be partly explained by the fact that in Thai postvocalic stops are normally unreleased, and the Thai listeners were less dependent on the release burst to identify the place of articulation of a postvocalic stop. The Thai listeners tended to identify voiced stops as voiceless stops of the same place of articulation. This may be because voiced stops cannot occur postvocalically in Thai.
Investigating the consonant-vowel boundary. II. Perceptual contributions of glimpse windows.
Authors: Fogerty Daniel , Kewley-Port Diane
Published: October 2013

Discrete segmental units do not occur in fluent speech because of coarticulation. However, separation of the meaningful sounds in language into the categories of consonants and vowels is one of the most fundamental principles of how sound is structured. Our previous research has shown that for sentence presentations, vowels have a distinct perceptual advantage over consonants in determining sentence intelligibility. TIMIT sentences were used to investigate perceptual contributions of consonants and vowels across the consonant-vowel (CV) boundary, by shifting the CV boundary by specific proportions of the vowel, such that consonant duration increased while vowel duration decreased. Glimpse windows are defined as the speech signal preserved between noise replacements. The perceptual effect of windows either locked to specific segmental information or placed randomly was examined. Results from glimpse windows locked to segmental information confirmed a 2-to-1 vowel advantage for intelligibility at the traditional CV boundary and suggest that vowel contributions remain robust against deletions of the signal. When glimpses were presented randomly, summed duration of glimpses predicted performance. However, performance remained lower than when glimpse windows of equivalent duration were locked to vowels. Specific segmental information appears to differentiate performance between consonant and vowel conditions. [Work supported by the NIH.]
Auralization as a tool for acoustical design of single family residences.
Authors: Rosenberg Carl , Sacks Jonah , Dugan Erin , McDonald David
Published: October 2013

Acoustical requirements play an increasing role in residential building design. In an effort to understand these changes USG Corp., a manufacturer of building materials and developer of acoustical solutions for residential and commercial markets, engaged Acentech Inc. to develop aural demonstrations, or auralizations, of common acoustical issues in single family residences. Using computer modeling and audio processing techniques, a number of convincingly realistic simulations of familiar residential scenarios were developed. These auralizations allowed USG to better understand acoustical issues and recommend appropriate products and systems. This paper shares the experience of this project.
Performance issues of resilient channels in wall systems.
Authors: Payne Stephen W.
Published: October 2013

There has been much recent discussions on the issue of proper installation of resilient channels. Of particular concern is the issue of the “shorting out” of the resilient channels, wherein the gypsum board attachment screws passes through the resilient channel and into the structural member. This paper will present the test results obtained during a series of tests to evaluate the significance of this issue. In addition data will be presented from a further study on the significance of the geometry of the resilient channel design.
Room sound absorption provided by underbench sound absorbing material.
Authors: Harght Pamela , Coffeen Robert
Published: October 2013

The concept that sound absorbing material added beneath “hard” benches and pews will be useful in the reduction in reverberation in religious worship facilities, and other places of assembly are occasionally advanced by facility owners and users who do not desire to employ bench and pew seat upholstery or seat cushions. This paper presents data on underbench sound absorption calculated from measurements made in a reverberant space with and without the addition of a sound absorbing material to the underside of wood benches.
Observed intensity and horizontal field coherence variability of low-frequency pulse transmissions on the continental shelf.
Authors: Duda Timothy F. , Collis Jon M. , Lin Ying-Tsong , Lynch James F.
Published: October 2013

Rapid coastal environmental evolution leads to highly variable acoustic fields. To quantify such variability, one component of the Shallow-Water 2006 (SW06) program on the shelf east of New Jersey was time series measurement of sound transmitted from fixed sources to joined horizontal and vertical line arrays. Transmission paths were both cross-shelf and along-shelf (across and along dominant internal-wave crests). Data were collected for over one month. Intensity time series of 100–400-Hz pulses was found to have strong variability at periods from hours to over a day, consistent with long-wavelength internal-tide effects. Such effects can arise from adiabatic mode and/or coupled mode propagation. Separation of fluctuations into slow and rapid contributions allows calculation of a time-varying horizontal coherence-length statistic. For along-wave crest transmission, this was highly variable, typified by values ranging from a few acoustic wavelengths to over 40 wavelengths, typically 10–25. The slow coherence-length fluctuations had signatures of periodic (tidal) mode-refraction episodes (with short scale) during active intervals, caused by internal-wave ducting. Conditions were more steady at other times. Across-crest transmissions showed shorter than expected scale lengths of tens of wavelengths with more subtle tidal dependence. [Work supported by the Office of Naval Research.]
Temporal fluctuations and coherencies of broadband signals observed during Shallow Water 2006.
Authors: Wylie Jennifer , DeFerrari Harry
Published: October 2013

A 50 h acoustic propagation experiment conducted during SW06 included receptions of broadband signals at three ranges with single hydrophone receiver units. 100–1600 Hz centered broadband signals were propagated through identical shallow channels during periods of low- and high-internal wave energies. Here, the transition from nearly perfect coherent and stable mode/ray arrivals to the formation of short live micromodes/ray arrivals is presented. The relative influence of volume scattering and bottom scattering is seen to shift with frequency; low frequencies see a smooth reflective bottom but have interaction with internal waves induced volume fluctuations, whereas higher frequencies are increasingly more sensitive to bottom scattering. Discrete mode arrivals give way to a continuum of numerous short lived arrivals with increasing frequency. For still higher frequencies, coherence times are shorter still and at some point the phase coherence is so reduced that signal processing gain is lost and the signals are no longer detectable. Ultimately, the performance of higher-frequency sonar and underwater communication systems will be limited by these effects. The limits of phase coherent gain for the 800 and 1600 Hz signals are estimated for this range site.
Investigation of an unusual noise phenomenon with horizontal and vertical hydrophone array data and three-dimensional propagation modeling.
Authors: Dossot Georges A. , Miller James H. , Potty Gopu R. , Lynch James F. , Newhall Arthur E. , Badiey Mohsen
Published: October 2013

Acoustic data from an experiment conducted during Shallow Water 2006 (SW06) showed an unexplained broadband noise phenomenon. While the R/V Knorr towed a J-15 acoustic source, which emitted a 93 Hz continuous-wave signal, the R/V Endeavor performed Scanfish measurements in the vicinity to characterize internal wave phenomena. The WHOI Shark horizontal and vertical hydrophone array detected the 93 Hz signal, but eventually the signal was overpowered by broadband low-frequency noise. The broadband noise may be associated with either research vessel but is uncharacteristically intense given that both vessels were greater than 25 km away from the Shark array. The complex acoustic environment due to the shelfbreak front, an internal wave packet, and the bathymetry of the continental shelf may have caused ducting of the noise field. Both three-dimensional acoustic modeling and array processing techniques will be used to characterize the unexplained noise levels. In situ data from temperature sensors and Scanfish measurements provide environmental information needed to accurately model the sound speed field. These methods can also be applied to other SW06 experiments that were tailored to investigate the role of internal waves in acoustic propagation—such as those carried out on the R/V Sharp. [Work sponsored by the Office of Naval Research.]
Sensitivity issues in acoustic mode tomography.
Authors: Chandrayadula Tarun K. , Wage Kathleen E.
Published: October 2013

Ocean acoustic mode tomography relies on a high signal to noise ratio and an accurate measure of the time of arrival for the mode signals. The low-order modes measured during tomography experiments such as the 2004 long range ocean acoustic propagation experiment (LOAPEX) are sensitive to environmental and experimental conditions. For example, internal waves can cause mode coupling and time of arrival perturbations. The source and the VLA move due to currents and tides, which results in Doppler spreading and frequency selective fading. Uncertainties in the signal affects the accuracy of tomographic methods. Previous work [Chandrayadula et al., J. Acoust. Soc. Am. 121, 3053 (2007)] mainly focused on building a channel model for the internal wave effects. This paper extends the previous work by building a more complete channel model that also includes the effects due to residual source/receiver motion. The statistics from the channel model are used to study the effect of uncertainties on the mode signals measured during LOAPEX. [Work supported by ONR Ocean Acoustics Graduate Traineeship Award.]
Analysis of movements for drumstick control using surface electromyograms.
Authors: Fujisawa Takuya , Iwami Naoki , Kinou Masafumi , Miura Masanobu
Published: October 2013

Skills in controlling drumsticks correctly and appropriately in drumming are required to play rhythms without mistakes at appropriate dynamic levels of sound. Results obtained by analyzing drummers’ movements from visual information, such as motion captures or camera recordings, have been reported in past studies, but analysis using biological information has been neither reported nor suggested to be employed. The aim of this study was to investigate the movements of drummers’ hands and fingers by recording their surface electromyograms (EMGs) when drumming. Three amateur drummers participated in an experiment to record drummers’ surface EMGs in playing single-stroke under three different conditions, such as “no-drum single-stroke,” “no-drumstick single-stroke,” and “normal single-stroke” at three different tempi of 80, 100, and 120 bpm. They were asked to play 16 measures of 4 beats under the tempi denoted above, and employed score in this experiment is simple, where four quarter-notes are simply allocated in a measure. Results of the experiment show that the average of surface EMG for playing no-drum single-stroke was significantly higher than that for normal single-stroke, indicating that drummers played single-stroke under lowest load in terms of muscle control. [Work supported by the HRC, Ryukoku Univ.]
On the need for context-sensitive noise impact criteria in rural communities.
Authors: Horonjeff Richard , Anderson Grant
Published: October 2013

With the growing population, infrastructure elements previously the exclusive province of urban and suburban communities are pushing their way into rural settings. In their wake comes increased noise nuisance and the need for context-sensitive community noise standards and guidelines. Major differences between urban and rural soundscapes make difficult the stretching of urban guidelines into rurality. Urban noise impact considerations are typically those of minimally increasing the pre-existing anthropogenic din; rural considerations center on maintaining the absence of din altogether. Most quantitative community noise standards are loudness based, comparing source loudness with that of the ambient. However, the desires of rural communities suggest that an audibility-based metric would better suit their needs. Current noise standards explicitly considering rural areas do so by recognizing the lower ambient sound levels in rural areas but still relying on loudness-based metrics. Thus, the need exists to examine the situation from an audibility perspective if places of solitude are to be preserved. This paper identifies the soundscape values of rural populations and compares them with those of urban dwellers. It then identifies the essential elements of noise metrics needed for rural soundscape preservation and also identifies the legal challenges encountered in protecting rural soundscapes.
Investigating lexical influences on the accuracy of speechreading words presented in isolation and in sentence context.
Authors: Auer Edward , Reed Rebecca
Published: October 2013

Isolated spoken words that are perceptually similar to many other words in the mental lexicon are typically more difficult to recognize than words that are perceptually unique. This effect has been demonstrated for spoken words presented in both auditory and visual presentation conditions. Here, this effect of perceptual similarity on visual recognition (speechreading) of spoken words was compared for words presented in isolation and in sentential contexts. Sentences were developed containing key words that varied in predicted perceptual uniqueness. 123 (41-easy, 41-moderate, 41-difficult) spoken sentences were presented visual-alone to 40 participants for identification. 301 keywords spoken in isolation were presented visual-alone to 23 participants for identification. In both presentation conditions, identification accuracy varied as a function of the perceptual similarity of the target word to other words in English. Specifically, identification accuracy decreased as the number of perceptually similar words increased. Furthermore, the effect of perceptual similarity interacted with presentation condition (isolated words versus sentence). The results suggest that the typical advantage afforded by perceptual uniqueness is reduced when words are presented in a sentence context. Implications for future modeling studies and for predicting the intelligibility of sentence length materials will be discussed. [Work supported by an NIH/NIDCD R01DC04856.]
Luxury isolation: Curtain wall construction and the impact on the expectation of acoustic isolation.
Authors: Giegold Carl , Norris Molly
Published: October 2013

Curtain wall construction is an aesthetically popular choice among architects for exterior glazing. It is often employed in luxury settings where the expectation of acoustic isolation is high, but the ability to achieve it is low. This is particularly an issue with regard to room-to-room isolation at curtain wall mullions. The author will present a case study involving the use of curtain wall construction in a high rise luxury hotel and including the issues with warranty and an alternative approach to improving the performance of these elements.
Using auditory evoked potentials to measure marine mammal hearing.
Authors: Nachtigall Paul
Published: October 2013

The use of auditory evoked potential (AEP) measurements for examining the hearing of marine mammals was accelerated by the need to rapidly test hearing following sound exposures during temporary threshold shift experiments. AEP measures have allowed quick measurements of hearing following intense noise exposures of sounds ranging from filtered white noise to 53-C sonars. The refinement of AEP hearing measurements with envelope following response measures leads to comparisons between behavioral and AEP hearing thresholds. These comparisons have allowed an expansion of basic hearing measurements including measures of new species such as the white-beaked dolphin and polar bear, measures of increased numbers of the same species in order to better examine population audiogram estimates and variability, and testing of hearing of animals in the field. AEP measures have also allowed the measurement of hearing during echolocation. A false killer whale has been shown to hear its own outgoing signal 40 dB down from the same sort of signal presented directly in front of it, actively control the level of its hearing of echolocation returns in an automatic gain control of hearing, and hear sounds other than echolocation sounds 20 dB differently when it is echolocating depending on target condition.
Temporary threshold shift: Sam Ridgway’s contribution to an important and not-so-temporary line of marine mammal research.
Authors: Schlundt Carolyn E. , Finneran James J. , Carder Donald A.
Published: October 2013

When the National Research Council formed a committee in 1992 to investigate the current knowledge and need for research on the potentially harmful effects of low-frequency sound on marine mammals, Sam Ridgway embarked on a course of study that is now entering its second decade. Following the committee recommendations and with the goal of providing long-term protection of the species, Ridgway initiated the first formal investigations of temporary threshold shift (TTS) in dolphins and white whales. Key to that effort was Ridgway’s development of a vocal response paradigm based on the method of free response, which allowed thresholds to be quickly estimated after noise exposure. Initial studies focused on short duration tones. Subsequent studies included single, intermittent, and impulsive sounds and have produced TTSs large enough to track growth and recovery. The resulting data reveal the effects of exposure frequency, sound pressure, duration, and temporal pattern. Recent success using auditory evoked potentials to measure TTS will enable many more subjects/species to be tested. As a result of Ridgway’s pioneering work, direct data now exist to predict the effects of noise on marine mammals and to develop acoustic exposure guidelines.