bluuebunny/crossref_metadata_2025 huggingface dataset:
Appropriate and inappropriate uses of classroom amplification
Authors: Lubman David , Sutherland Louis C.
Published: October 2013

Currently, classroom amplifiers are being aggressively advocated as substitutes for good acoustics in small mainstream classrooms. Amplifiers are routinely installed without regard to unoccupied classroom noise levels and reverberation times. Amplifiers are being specified by some school districts as a money-saving alternative to mandating compliance with the ANSI standard on classroom acoustics, S12.60-2002. Manufacturers of portable classrooms and noisy wall mounted HVAC systems have joined in supporting the use of classroom amplifiers, claiming that low (35 dBA) classroom noise levels specified by the ANSI standard are unaffordable and unnecessary given amplifiers. The authors believe that the routine use of classroom amplification is appropriate in very large lecture rooms, in special education classrooms for hearing impaired students, for voice-impaired occupants, and perhaps in certain other limited circumstances. The authors explain why they believe the routine use of amplifiers in small mainstream classrooms is an inappropriate substitute for the good classroom acoustics specified in the ANSI standard.
Quantifying nonlinearity in the propagation of noise from military jet aircraft
Authors: Gee Kent L. , Sparrow Victor W.
Published: October 2013

Because of the high noise levels radiated by military jet aircraft, it has been hypothesized that nonlinearity influences the propagation of the noise. A numerical model, which accounts for second-order cumulative nonlinearity, atmospheric absorption and dispersion, and geometrical spreading, has been developed to propagate jet noise waveforms. Numerical propagation of recorded waveforms from recent static engine run-up measurements demonstrates significant waveform steepening and an accompanying transfer of spectral energy to high frequencies that agrees well with measured spectra. Furthermore, the measured and nonlinearly predicted waveforms are perceived to be significantly ‘‘louder’’ or ‘‘more annoying’’ than linearly predicted waveforms, despite the fact that standard metrics such as overall sound pressure level (with flat-, A-, and C-weighting) and Stevens Mark-VII perceived loudness show little difference between linearly and nonlinearly predicted spectra. The results of this study demonstrate the need for additional investigations with alternate metrics that more closely relate to perceived annoyance or loudness of high-amplitude jet noise. [Work supported by the Strategic Environmental Research and Development Program.]
Nonlinear propagation modeling: Guidelines for supporting measurements
Authors: Gabrielson Thomas B. , Marston Timothy M. , Atchley Anthony A.
Published: October 2013

In nonlinear propagation, evolution of waveforms is strongly dependent on the characteristics of the waveform. The commonly observed waveform steepening is a coherent process that produces a specific phase relationship between spectral components. High-amplitude military jet noise may show peak pressures five to ten times the root-mean-square pressure and may have local rise times less than several microseconds. Measurement of these waveforms containing fast rise times requires large bandwidth and high fidelity in phase. If the bandwidth and phase are not preserved then the waveforms can lose precisely those features that distinguish them from linear propagation. Whether such waveforms are used as starting fields for nonlinear codes or as code validation, the impact of limitations in the measurement system must be understood—the simple frequency-response magnitude is insufficient. By generating freely propagating weak-shock waves with rise times comparable to those observed in full-scale jet measurements, the time-domain response (or, equivalently, the magnitude and phase response) was determined for a number of sensor configurations. Taken together with full-scale jet-noise data, these results suggest guidelines for making or using field measurements when those measurements are intended to support nonlinear modeling efforts.
Evaluation of urban scape—a combined approach of acoustics and architecture
Authors: Bauer Juergen
Published: October 2013

Related to a concept of integrating acoustics into architectural education a new model of designing will be introduced. Combined noises as well as soundscapes with its specific view points on measurement procedures will be discussed against urban fabrics.
Model community noise ordinance—A new approach to community based policy
Authors: Brooks Bennett M. , Finegold Lawrence S.
Published: October 2013

This paper describes the progress of work ongoing to develop a model community noise ordinance as a U.S. American National Standards Institute (ANSI) national Standard. The Standard expected to result from the efforts of ANSI S12 (Noise) Working Group 41 will provide guidance to governmental officials, acoustical consultants, and other interested persons on how to develop a community noise ordinance which is appropriate for the existing local circumstances, including issues such as public and government priorities and values, available resources, etc. It will give local communities a technical basis for being able to manage their local sound environment and will be sufficiently flexible to be tailored to the needs of a variety of urban, suburban, and rural communities. The key to the usefulness and effectiveness of this new Standard is that it will provide a ‘‘menu’’ of options and will also provide brief discussions of the tradeoffs involved for decisions that must be made by government officials. It will also emphasize that enforcement of a community noise ordinance is crucial to its success and will provide a means to accomplish this important function.
Soundscape measurements: Moving towards a standard
Authors: Kull Robert
Published: October 2013

Soundscapes are multidimensional and require a more robust examination of the influences and effects of the environment. The spectrum of soundscapes spans the continuum from completely natural environments to entirely urban. The approach has to make assumptions and generalizations of the contribution of anthropogenic and non-anthropogenic sources and to determine which aspects of soundscapes are measurable. Step-by-step procedures on how to fill a model with data, including a basic discussion about the kind of measurements that have to be carried out, will be discussed. There will also be discussion as to whether the same measurement procedure is appropriate with respect to animals and humans and the requirements to develop a standard concerned with soundscape evaluation.
Noises from combined sources—are there any standards?
Authors: Schulte-Fortkamp Brigitte
Published: October 2013

Combined noises have to be investigated with regard to their effects on the encumbrance of the inhabitants of residential areas. As far as noise encumbrance and its effects are concerend, investigating the level of loudness is not sufficient. Furthermore, it is of central importance to investigate the sounds from different sources in the context of everyday life activities, expectancies and different life situations. Therefore, certain methods of investigation and assessment have to be applied with whose help encumbrances caused by noises from different sources can be analyzed. Combining socioacoustical and psychoacoustical methods gives the opportunity to reveal direct connections between subective understanding and subjective perception. Moreover, with the help of this combination noise can be assessed and characterized; psychoacoustical parameters as well as noise emmission can be analyzed in detail. The question is whether there are any standards with respect to combined sources which meet this difficult assessment. As an example the first draft of a German standard will be discussed.
Working with Cyril M. Harris at Benaroya Hall
Authors: Hoover Robert M. , Taylor Ashton
Published: October 2013

To contribute to a project such as Benaroya Hall, now the home of the Seattle Symphony Orchestra, as team members of acoustical giant Cyril M. Harris was a golden opportunity for Robert M. Hoover and Ashton Taylor. Their involvement in the project and association with Cyril began at the early stages of the project as consultants in noise control. During the schematic design phase, Cyril dictated to the LMN Architects design team that authority for all noise control decisions rested with Bob Hoover. This led to good working relationships, especially with the mechanical engineering firm and the air-conditioning contractor. Throughout the project, Cyril insisted upon the highest standards of materials and workmanship, and relied on the expertise of his acoustical design team, even if it went against his initial idea on some issue. At the beginning with the setting of noise criteria and in the finished building when measuring background sound, Cyril participated in the noise control process. Benaroya Hall has been critically acclaimed by the media and musicians, it was an honor for both Bob Hoover and Ashton Taylor to be part of that success.
Cyril M. Harris: Acoustician, educator, and mentor
Authors: Raichel Daniel R.
Published: October 2013

Cyril M. Harris belongs to that rare breed of technologists who excel in more than one aspect of acoustics. His achievements are legendary in the realms of architectural acoustics, physical acoustics, ultrasound, and speech processes. He coauthored with Vern O. Knudsen a classic text on architectural acoustics and served as editor of several major references. He also excelled as a teacher and mentor. When the author set up the Acoustics Research Center at the Cooper Union, Dr. Harris came over to see the new facility. At my invitation, he gave a lecture before an audience constituted of engineering and architectural students; one surely had to rate this event as one of the best seminars ever given at that institution. When I wrote The Science and Applications of Acoustics, Dr. Harris was generous in giving me permission to use a number of figures from his published texts. He also sent me students from Columbia to use the acoustic facilities at Cooper. One of his referees, a master’s degree candidate, conducted a major study on Guastavino tiles for this thesis, which resulted in a prize-winning publication. The manifold accomplishments, influence, and legacy of Cyril Harris will surely resonate for generations to come.
The psychology of songbird acoustic communication: Open-ended categorization and its role in songbird perception
Authors: Sturdy Christopher
Published: October 2013

Songbirds are used as a model system for understanding vocal learning, production, and perception. Over the past several years one particular aspect of songbird communication has been examined, vocal perception that has parallels with human speech perception, namely, the perception of natural acoustic categories in songbird vocalizations. A series of studies will be presented highlighting the role of open-ended categorization in the perception of vocalizations in songbirds. Attempts will be made to make the case that open-ended categorization is a fundamental proximate mechanism for acoustic communication in both humans and songbirds, that it is used in a highly analogous manner in each, and future directions will attempt to integrate these two areas of research and, ultimately, lead to a more complete understanding of acoustic communication in animals.
Long-term memory of heterospecific vocalizations by African lions
Authors: Grinnell Jon , van Dyk Gus , Slotow Rob
Published: October 2013

Animals that use and evaluate long-distance signals have the potential to glean valuable information about others in their environment via eavesdropping. In those areas where they coexist, African lions (Panthera leo) are a significant eavesdropper on spotted hyenas (Crocuta crocuta), often using hyena vocalizations to locate and scavenge from hyena kills. This relationship was used to test African lions’ long-term memory of the vocalizations of spotted hyenas via playback experiments. Hyena whoops and a control sound (Canis lupus howls) were played to three populations of lions in South Africa: (1) lions with past experience of spotted hyenas; (2) lions with current experience; and (3) lions with no experience. The results strongly suggest that lions have the cognitive ability to remember the vocalizations of spotted hyenas even after 10 years with no contact of any kind with them. Such long-term memory of heterospecific vocalizations may be widespread in species that gain fitness benefits from eavesdropping on others, but where such species are sympatric and often interact it may pass unrecognized as short-term memory instead.
Communication calls of Japanese pipistrelle bats: Examination by acoustic characteristics
Authors: Osawa Yoshiki , Kondo Yoko , Nagato Tsuyoshi , Watanabe Yoshiaki , Riquimaroux Hiroshi
Published: October 2013

We classified communication calls of Japanese pipistrelle bats (Pipistrellus abramus) by acoustic characteristics D. The Japanese pipistrelles emitted communication calls that were completely different from FM echolocation calls. Data showed that in general duration of communication calls was longer than that of echolocation calls (e.g., echolocation call, 1 ms; long CF communication call, 50 ms) and that frequency of commu-nication calls were lower than that of echolocation calls (e.g., echolocation call, 80–40 kHz; long CF communication call, about 14 kHz). Typical classified communication calls were as follows: slightly short CF call (20 ms, 14 kHz), short CF call (5 ms, 14 kHz), slightly long CF call (30 ms, 14 kHz), long CF call (50 ms, 14 kHz), slightly long FM call (15 ms, 30–15 kHz), long FM call (20 ms, 25–15 kHz), complicated FM call (10–50 ms, 25–15 kHz), short intermittent CF call (1 ms, 14 kHz) and noise call (20–100 ms, below 60 kHz). Details will be discussed more specifically. [Research supported by a grant to RCAST at Doshisha Univ. from MEXT and by the Innovative Cluster Creation Project promoted by MEXT.]
Real-time monitoring of ultrasound imaging of clinical high intensity focused ultrasound (HIFU) exposures
Authors: ter Haar Gail , Kennedy James , Leslie Tom , Wu Feng
Published: October 2013

Currently, many clinical devices use the change in gray scale seen on a real-time ultrasound image for the assessment of the success of HIFU treatment. It has been shown previously that, for a single HIFU lesion, the presence of gray-scale change was indicative of successful ablation in 100% of cases for 1.6-MHz beams, and in 90% of cases for 0.8-MHz exposures. The absence of gray-scale change was a reliable indicator of lack of ablative damage only for 0.8-MHz exposures (80%); in 80% of exposures using 1.6-MHz beams there was a lesion even in the absence of gray-scale change. This study has been extended to more realistic clinical treatment protocols. The image appearance has been studied for the different volume ablation techniques that are used in the treatment of liver and kidney cancer. The results will be presented.
Monitoring high-intensity focused ultrasound (HIFU) therapy using radio frequency ultrasound backscatter to quantify heating
Authors: Kaczkowski Peter J. , Anand Ajay
Published: October 2013

The spatial distribution and temporal history of tissue temperature is an essential indicator of thermal therapy progress, and treatment safety and efficacy. Magnetic resonance methods provide the gold standard noninvasive measurement of temperature but are costly and cumbersome compared to the therapy itself. We have been developing the use of ultrasound backscattering for real-time temperature estimation; ultrasonic methods have been limited to relatively low temperature rise, primarily due to lack of sensitivity at protein denaturation temperatures (50−70°C). Through validation experiments on gel phantoms and ex vivo tissue we show that temperature rise can be accurately mapped throughout the therapeutic temperature range using a new BioHeat Transfer Equation (BHTE) model-constrained inverse approach. Speckle-free temperature and thermal dose maps are generated using the ultrasound calibrated model over the imaged region throughout therapy delivery and post-treatment cooling periods. Results of turkey breast tissue experiments are presented for static HIFU exposures, in which the ultrasound calibrated BHTE temperature maps are shown to be very accurate (within a degree) using independent thermocouple measurements. This new temperature monitoring method may speed clinical adoption of ultrasound-guided HIFU therapy. [Work supported by Army MRMC.]
MRI guidance for focused ultrasound surgery
Authors: McDannold Nathan , Hynynen Kullervo
Published: October 2013

Magnetic resonance imaging (MRI) based monitoring has been shown in recent years to enhance the effectiveness of minimally or noninvasive thermal therapy techniques, such as focused ultrasound surgery. MR imaging’s unique soft tissue contrast and ability to image in three dimensions and in any orientation make it extremely useful for treatment planning and for imaging the tissue response to the therapy. The temperature sensitivity of several intrinsic parameters enables MRI to visualize and quantify the progress an ongoing thermal treatment. The most useful temperature-sensitive parameter appears to be the proton resonant frequency, which allows for precise and accurate temperature measurements in water-based tissues. By acquiring a time series of quantitative temperature images, it is possible to monitor the accumulated thermal dose delivered to the target tissue and accurately predict the areas that are thermally ablated, while at the same time ensuring nearby critical structures are not heated. The method is currently used in an FDA approved focused ultrasound device for the treatment of uterine fibroids. Our research and clinical experience with these techniques will be reviewed.
Determination of transmission loss of materials from array measurements using nearfield acoustical holography/inverse boundary element methods in a transmission loss facility
Authors: Williams Earl G. , Valdivia Nicolas , Herdic Peter , Klos Jacob , Palumbo Daniel , Silcox Richard , Sklanka Bernard
Published: October 2013

A new approach for the measurement of transmission loss based on NAH is discussed in this paper. Two array configurations were tested to determine the transmission loss of sound isolation materials applied to an aircraft fuselage panel in Boeing’s interior noise test facility (INTF). The first configuration consisted of a 120 element planar array positioned conformal to the fuselage panel surface in the anechoic side of the TL facility. A second configuration used 50 microphones in a spherical array of diameter 0.4 meters placed in front of the panel. The normal intensity on the surface of the fuselage panel isolation layer was reconstructed using NAH/IBEM (nearfield acoustical holography/inverse boundary element methods) using partial fields generated from a set of reference accelerometers. The panel excitation was random plane wave fields generated in the reverberation room of the TL facility. This new approach measures the TL in narrow bands or 1/3 octave bands from 50 to 2 kHz, and is shown to be very accurate when compared with conventional TL measurements. This approach also provides the normal panel vibration for each partial field so that panel modes can be uncovered and studied. Furthermore, the spherical array provides a reconstruction of the vector acoustic intensity in the volume in front of the panel so that the magnitude and direction of the transmitted energy fields can be mapped.
Theory of patch inverse boundary element method (IBEM)
Authors: Valdivia Nicholas , Williams Earl G. , Herdic Peter , Klos Jacob , Palumbo Daniel , Silcox Richard , Slanka Bernard
Published: October 2013

Near-field acoustical holography (NAH) based on boundary element methods require the measurement of the near-field pressure field over a conformal and close surface in order to recover the acoustic field on a nearby surface. In this work a new technique called patch IBEM is introduced. This new technique eliminates the need to measure over an entire closed surface, but instead the measurements are taken over a small area to reconstruct the acoustic field. Patch IBEM is used for the reconstruction of the acoustic field over a fuselage panel in a Boeing 757 aircraft, using measurement taken at Boeing’s interior noise test facility (INTF). The measurements taken include a 120 mikes planar array positioned conformal to the fuselage panel surface and a 50 mikes spherical array. Results will be showed when the fuselage panel is excited by a shaker. [Work supported by ONR and NASA.]
Noise, vibration and harshness (NVH) criteria as functions of vehicle design and consumer expectations
Authors: Raichel Daniel R.
Published: October 2013

The criteria for NVH design are to a large degree determined by the types of vehicles and the perceived desires of the purchasers of vehicles, as well as the cost of incorporating NVH measures. Vehicles may be classified into specific types, e.g., economy car, midsize passenger, near-luxury and luxury passenger cars, sports cars, vans, minivans, and sports utility vehicles of varying sizes. The owner of a luxury sedan would expect a quiet ride with minimal vibration and harshness—however, if that sedan is to display sporting characteristics, some aspects of NVH may actually have to be increased in order to enhance a feeling of driver exhilaration. A discussion of the requirements for specific types of vehicles is provided, with due regard for effects on the usability of installed sound/video systems, driver and passenger fatigue, feel of steering mechanisms and other mechanical components, consumer market research, etc. A number of examples of vehicles on the market are cited.
Observed cause-effect relationships between measured aircraft sound exposure levels and various predictor variables
Authors: Horonjeff Richard D. , Senzig David A. , Anderson Grant S.
Published: October 2013

Sound exposure levels of in-service jet aircraft departures at a single airport were measured along with a number of potential explanatory variables to determine the extent of cause-effect relationships under typical uncontrolled operating conditions. Explanatory variables included aircraft type, installed engine type, aircraft gate weight, aircraft operator, 10-meter wind velocity, temperature, relative humidity, and barometric pressure. The two factors having the greatest influence on measured SELs (within aircraft type) were (1) a linear association with gross weight and (2) a logistic association with air density (or density altitude). The logistic relationship with air density shows an asymptotic functional form at extreme density values suggestive of full takeoff power under low air density conditions, and lower power settings under high air densities. Together, gross weight and air density alone explained 80 percent of the measured SEL variance. The remaining variables appeared to show little affect for the aircraft types investigated, with the exception of headwind component at speeds in excess of 15 knots. These relationships, along with the integrated noise model’s (INM) ability to predict them, are presented. Also presented are differences in computed annual average SELs using single, annual average predictor values of the variables versus separate, seasonally averaged ones.
Quality at a price you can afford
Authors: Garrett Steven , Smith Robert , Poese Matthew
Published: October 2013

The transition of thermoacoustics from the laboratory to the commercial sector involves a process that is very different from science. In the laboratory, when an experiment fails to produce the expected result, it is possible to make modifications, followed by further measurements, to isolate the discrepancy. After discussions with nearly 40 different companies over the past 5 years, there is rarely any feedback about why a given company decides not to proceed. In such an open-loop environment, we are left with only speculation regarding this obscure process. This talk will postulate some reasons that have led to our failure, thus far, to team with an early adaptor of the technology. These include their general lack of familiarity with acoustics, difficulties surrounding licensing of existing and future intellectual property controlled by a university, and the drift away from the maintenance of an active in-house research capability in industry [see H. W. Chesbrough, Open Innovation (Harvard, 2003)]. The sequence of events that lead to formation of the ThermoAcoustics Corporation, an investor-funded start-up, will be related, along with the changes that licensure of intellectual property have made to our ability to deal with industry on a business-to-business basis without intervention of university tech-transfer professionals.
Capillary-tube-based extension of thermoacoustic theory for a random medium
Authors: Roh Heui-Seol , Raspet Richard , Bass Henry E.
Published: October 2013

Thermoacoustic theory for a single capillary tube is extended to random bulk medium on the basis of capillary tubes. The characteristics of the porous stack inside the resonator such as the tortuosity, dynamic shape factor, and porosity are introduced for the extension of wave equation by following Attenborough’s approach. Separation of the dynamic shape factor for the viscous and thermal effect is adopted and scaling using the dynamic shape factor and tortuosity factor is demonstrated. The theoretical and experimental comparison of thermoviscous functions in reticulated vitreous carbon (RVC) and aluminum foam shows reasonable agreement. The extension is useful for investigations of the properties of a stack with arbitrary shapes of non-parallel pores.
Thresholds for a tone masked by constant, remote-frequency maskers
Authors: Werner Lynne A. , Leibold Lori J.
Published: October 2013

In an experiment examining informational masking in infants, Leibold (2004) reported that infants and adults exhibited masking of a tone by two tones of constant, remote frequencies. Neither informational nor energetic masking would be expected for adults under these conditions. In the present experiment, adults’ detection of a tone masked by two constant frequency tones or two narrow bands of noise were compared. Fifteen young adults participated. The target tone was 1000-Hz, 300-ms duration with 16-ms rise/fall. Unmasked and two masked thresholds were estimated. The maskers were either tones of 581 and 2920 Hz or 50-Hz-wide noise bands centered at 556 and 2895 Hz. The duration of the maskers was 300 ms with 16-ms rise/fall. A one-interval adaptive procedure was used to estimate thresholds. The maskers repeated at 600-ms intervals. The target tone was presented simultaneously with the maskers on signal trials. Listeners received feedback whenever they correctly detected the target. About 75% of listeners demonstrated masking in both conditions, but the threshold in the two-noise condition was generally higher than in the two-tone condition. Thus, introducing a timbre difference between the target and masker did not reduce the amount of masking.
Effects of reduced spectral uncertainty and masker fringes with multitonal maskers
Authors: Leibold Lori J. , Neff Donna L. , Jesteadt Walt
Published: October 2013

This study examined the degree to which masker spectral uncertainty contributes to the high thresholds often observed with random-frequency, multitonal, simultaneous maskers. Masked thresholds for four normal-hearing adults were measured for a 1000-Hz, 200-ms signal presented with broadband-noise or multitonal maskers with 2 or 10 components. The multi-tonal maskers were 70 dB SPL and had a 160-Hz spectral gap centered at the signal. Two sets of conditions, using a 2AFC adaptive task, manipulated the degree of spectral uncertainty (masker randomized with each presentation vs fixed throughout a block of trials) and the temporal offset of the masker (masker equal to signal duration vs. masker increased to 400 ms, with a 100-ms fringe preceding and following the signal). A third set of ‘‘molecular’’ conditions, using a yes-no adaptive task, measured thresholds with five samples of multitonal maskers, either randomizing samples across trials or using one sample throughout trial blocks. For both large-set and molecular conditions, results showed as much as 30-dB release from masking when spectral uncertainty was reduced for fixed compared to random conditions. Fixed-frequency conditions, however, showed a further masking release with the masker fringe, with effects as large as 12 dB, variable across listeners. [Work supported by NIDCD.]
Critical ratio for tones, modulated tones and noise, and speech
Authors: Lovitt Andrew , Allen Jont
Published: October 2013

The critical ratio (CR) is a very basic concept first introduced in 1930 [Fletcher and Munson, (1933)], but rarely studied today. In this study we have remeasured the CR for a host of signals, including long duration tones, AM modulated tones at various modulation depths, at 3 Hz modulation, at several levels, modulated noise at two modulation depths levels, and speech signals of several bandwidths. A simple peak detection model explains most of the data. Some subject differences are also of interest.
Introduction and practical use of an algorithm for the calculation of pitch strength
Authors: Fruhmann Markus
Published: October 2013

Pitch strength is a psychoacoustic magnitude describing how strong the pitch of a sound can be perceived. Introduced in 1979 by Fastl and Stoll, a large variety of experimental data has been collected, but no model has been established so far to describe the data found. In the talk, some data to give an overview of pitch strength will be shown. Based on a transform taking into account the properties of the human auditory system, namely the Fourier-t-transform, an algorithm was developed to calculate pitch strength. Calculated data will be compared to the corresponding experimental data showing the potential of the algorithm. Furthermore, the measure of pitch strength will be discussed in the context of tonality which describes the perceivability of single tonal components within a sound. Tonality is subject of several industrial standards (e.g., DIN 45681) to judge the sound quality of noises from mechanical structures and machines. Pitch strength data show several similarities when compared to tonality, but as a more global percept it also shows differences especially in the cases where virtual pitch is evoked.
Detection and discrimination of monaural and binaural increments and decrements of intensity with a temporal fringe
Authors: Stellmack Mark A. , Viemeister Neal F. , Byrne Andrew J.
Published: October 2013

Detection thresholds are larger for brief, monaural intensity increments in long-duration stimuli than for decrements. This experiment assessed the contribution of a decrement in one ear to direction discrimination of an interaural intensity difference (IID), where a brief intensity increment was presented at one ear and an equal-magnitude intensity decrement at the other. In two-interval monaural tasks, thresholds were measured for detection of an increment, a decrement, and discrimination of the two. In single-interval binaural tasks, thresholds were measured for identifying ear of presentation of an increment, a decrement, and for identification of direction of IID achieved by presenting an increment and decrement to opposite ears. In all cases, thresholds were measured for a 5-ms probe segment as a function of its temporal position in a 50-ms stimulus (broadband noise). The major results: (1) Thresholds for discriminating the ear of presentation of a decrement were much larger than those for simply detecting the decrement monaurally; (2) Interaural thresholds were slightly better when both increment and decrement were present relative to increment alone. These results indicate that the decrements contributed to binaural discrimination, although by themselves the same decrements were detectable but, at best, weakly lateralizable. [Work supported by NIDCD DC00683.]
Coupling of head and body movements to acoustic flow in sighted adults
Authors: Stoffregen Thomas A. , Kim ChungGon , Ito Kiyohide , Bardy Benoit G.
Published: October 2013

Blindfolded sighted persons were found to detect acoustic flow patterns and use this information to control action. A moving room (a large box on wheels, with no floor, that moved in the subject’s fore–aft axis) was used. Blindfolded sighted persons (1) stood comfortably or (2) moved their head backward and forward to track audible room motion. Pink noise was presented through four speakers attached to the room, or mounted on stationary stands. Room motion was a sinusoid at 0.2 Hz, 22 cm, along subject’s fore–aft axis. When standing comfortably, participants exhibited weak but consistent coupling of body sway with room motion. Tracking of room motion with head movements was robust, matching both the frequency and amplitude of room motion. This was true even when the only information about room motion came from reflected sound (i.e., when the speakers were stationary). The results suggest a strong ability of sighted persons to use acoustic flow in the perception and control of their own action. [Work supported by NSF (BCS-0236627).]
Model for noise-induced hearing loss using support vector machine
Authors: Qiu Wei , Ye Jun , Liu-White Xiaohong , Hamernik Roger P.
Published: October 2013

Contemporary noise standards are based on the assumption that an energy metric such as the equivalent noise level is sufficient for estimating the potential of a noise stimulus to cause noise-induced hearing loss (NIHL). Available data, from laboratory-based experiments (Lei et al., 1994; Hamernik and Qiu, 2001) indicate that while an energy metric may be necessary, it is not sufficient for the prediction of NIHL. A support vector machine (SVM) NIHL prediction model was constructed, based on a 550-subject (noise-exposed chinchillas) database. Training of the model used data from 367 noise-exposed subjects. The model was tested using the remaining 183 subjects. Input variables for the model included acoustic, audiometric, and biological variables, while output variables were PTS and cell loss. The results show that an energy parameter is not sufficient to predict NIHL, especially in complex noise environments. With the kurtosis and other noise and biological parameters included as additional inputs, the performance of SVM prediction model was significantly improved. The SVM prediction model has the potential to reliably predict noise-induced hearing loss. [Work supported by NIOSH.]
The production of the /d/–/t/ distinction in French at slow speaking rate
Authors: Abdelli-Beruh Nassima
Published: October 2013

This study examined how monolingual French speakers produced the /d/–/t/ distinction at normal and slow speaking rates. Target syllables were preceded by a voiceless fricative (/s/). Voicing-related differences in durations of preceding vowel, /s/, stop closure, and VOT were calculated and analyzed as a function of speaking rate (stressed syllables spoken at normal speaking rate, stressed syllables spoken at low speaking rate). Percentages of /s/ and /d/ closures with voicing were tallied in each speaking rate condition. Results from ANOVA showed that the absolute durations in sentence, preceding vowel, /s/, and closure were larger in the slow speaking rate condition than in the normal speaking rate condition. The voicing of the /s/ preceding /d/ and during the closure of /d/ occurred systematically in the normal speaking rate condition. However, in the slow speaking rate condition, most speakers failed to phonate the /s/, but partially phonated the /d/ closures. The effects of slow speaking on the /d/–/t/ distinction are compared with the effects obtained in the unstressed speaking rate condition.
Variation in Rioplatense Spanish /s/ + stop sequences
Authors: Temkin Martinez Michal
Published: October 2013

This acoustic study of Rioplatense Spanish examines the lenition of syllable-onset, voiced stops after /s/. Four Rioplatense speakers from Buenos Aires participated in an acoustic experiment by reading sentences with the target stop occurring in phrase-initial, word-initial, and word-medial positions in both a conversational and clear speech style. Stop tokens at all three places of articulation were analyzed for the presence of voicing, of a stop-closure interval, and of a release burst. The variable realization of the preceding coda /s/ in all conditions was also transcribed and analyzed, to evaluate co-occurrence patterns in the sequence. The results indicated frequent occurrences of stop spirantization in the conversational style and in phrase-medial positions. Further, variants of /s/ containing only a laryngeal gesture, such as [h], co-occur with spirantized variants of the voiced stops. An articulatory phonology account is presented of the variation in stop realization, as well as of the relationship between the /s/ variant and its following stop. [Work supported by NIH.]
English vowel production by native Mandarin speakers: Influences of AoA, LoR, education, perception, and orthography
Authors: Bell-Berti Fredericka , Yu Yan Helen
Published: October 2013

This study investigates relations among several factors that are expected to influence vowel production in second language learning, including AoA, LoR, L2 and general education, L2 perception, and orthography. Vowel production will be examined through duration and formant frequency measurements and listener identification. The results will be analyzed in relation to educational background and language use. Among the educational factors examined are general education level, English education (in their native land and/or New York City), and sound-annotating system experiences in Mandarin (Pinyin or Zhuyin). The language-use factors include AoA, LoR, language spoken at work and at home, and perception of English vowels. The hypotheses addressed include: (1) educational background, language use, and sound-annotating system experiences in Mandarin all influence L2 English speakers perception and production of English vowels; (2) the more accurately an L2 listener discriminates a vowel contrast, the more distinctly he/she produces that contrast.
To play or to pray?–The influences of initial exposure age and environment on perception of Mandarin speakers of English on devoiced liquids
Authors: Chen Sally , Fon Janice
Published: October 2013

The devoicing rule of liquids after voiceless aspirated stops presents difficulty for L2 English learners. This study investigates Mandarin speakers’ perception of the rule with regards to initial exposure age and environment. Three initial exposure ages were included in this study: kindergarten, elementary, and junior high school. Except for the last group, each group was further divided into two exposure environments: Taiwan and the U.S. As a result, five groups of people were included in total, resulting in 25 subjects. Stimuli were pseudo-words in an SLV structure, recorded by one native English speaker and one non-native English speaker. Half of the stimuli began with a voiceless stop, and the other half began with a voiced stop. The native speakers pronounced the voiceless liquids accordingly while the non-native speaker only had voiced liquids. Preliminary results showed that, in general, L2 learners took longer time in perceiving devoiced liquids. Listeners who had earlier exposure were more likely to respond faster to native speech while late learners responded better to non-native speech.
The role of linguistic experience on the perception of phonation
Authors: Esposito Christina
Published: October 2013

This study investigates the role linguistic experience has on the perception of phonation and the acoustic properties that correlate with this perception. Listeners from three languages (Gujarati, which contrasts breathy versus modal vowels, Italian, which has no breathiness, and English, which has allophonic breathiness) participated in two tasks. In the Visual Sort task, breathy and modal vowels from a variety of languages (e.g., Chong, Mon, etc.) were presented as icons on a computer screen. Subjects sorted the icons (the stimuli) into two groups based on perceived similarity of the talker’s voices. In the multidimensional scaling task, listeners heard pairs of Mazatec vowels, and moved an on-screen slider to indicate the perceived similarity of the vowels in each pair. Results will show that judgments were more uniform across subjects who had breathy categories present in their native language(s), and varied across subjects who lack a breathy category. The perceived similarity among the stimuli will correlate with a measurable acoustic property (H1-H2, H1-H2, H1-A3, H1-A1 or H1-A2, the average of H1-H2 compared to A1, and A2-A3). It is hypothesized that H1-H2 will be the most salient acoustic property for Gujarati listeners because this correlates with their production of breathy vowels.
Reference frame and scaling in the perception of pitch in a tone language
Authors: Avelino Heriberto
Published: October 2013

Listeners can make subtle judgments about the relative magnitudes of auditory objects but only rarely make judgments of the absolute size of speech stimuli. In a pioneering paper, and his first publication in 1957, Peter Ladefoged demonstrated that the relative size of the surrounding context affects the perception of vowel quality. Although, years later, Ladefoged showed that the effect is only valid under certain conditions, the effect is still a motivated perceptual phenomenon. In this paper, the role of the reference frame in the perception of pitch in Yalalag Zapotec is investigated. YZ has three phonemic tones, high, low, and falling. Minimal pairs of H and L tones were introduced by a carrier sentence. The experiment manipulated the F0 of the Zapotec equivalent sentence to ‘‘Please say what this word is,’’ while the target words were kept unmodified. Other things being equal, the only difference was the F0 of six versions of the introductory sentence. Preliminary results are analogous to Ladefoged’s original findings on the identification of vowels: listeners’ pitch judgments are influenced by the overall auditory context in which they occur. The results suggest that perception of pitch for listeners of tone languages depends on allocentric frames of reference.
Factors affecting the perception of Korean-accented American English
Authors: Cho Kwansun , Harris John G. , Shrivastav Rahul
Published: October 2013

This experiment examines the relative contribution of two factors, intonation and articulation errors, on the perception of foreign accent in Korean-accented American English. Ten native speakers of Korean and ten native speakers of American English were asked to read ten English sentences. These sentences were then modified using high-quality speech resynthesis techniques [STRAIGHT; Kawahara et al., Speech Commun. 27, 187–207 (1999)] to generate four sets of stimuli. In the first two sets of stimuli, the intonation patterns of the Korean speakers and American speakers were switched with one another. The articulatory errors for each speaker were not modified. In the final two sets, the sentences from the Korean and American speakers were resynthesized without any modifications. Fifteen listeners were asked to rate all the stimuli for the degree of foreign accent. Preliminary results show that, for native speakers of American English, articulation errors may play a greater role in the perception of foreign accent than errors in intonation patterns. [Work supported by KAIM.]
Second language vowel training using vowel subsets: Order of training and choice of contrasts
Authors: Nishi Kanae , Kewley-Port Diane
Published: October 2013

Our previous vowel training study for Japanese learners of American English [J. Acoust. Soc. Am. 117, 2401 (2005)] compared training for two vowel subsets: nine vowels covering the entire vowel space (9V condition); and the three more difficult vowels (3V condition). Trainees in 9V condition improved on all vowels, but their identification of the three more difficult vowels was lower than that of 3V trainees. Trainees in 3V condition improved identification of the trained three vowels but not the other vowels. In order to further explore more effective training protocols, the present study compared two groups of native Korean trainees using two different training orders for the two vowel subsets: 3V then 9V (3V-9V); and 9V then 3V (9V-3V). The groups were compared in terms of their performance on all nine vowels for pre-, mid-, and post-test scores. Average test scores across the two groups were not different from each other. A closer examination indicated that group 3V-9V did not improve on one of the three more difficult vowels, whereas group 9V-3V improved on all three vowels, indicating the importance of training subset order. [Work supported by NIH DC-006313 and DC-02229.]
Some novel allophonic and phonemic phenomena in Biscayan Basque
Authors: Campos-Astorkiza Rebeka
Published: October 2013

An acoustic study of novel allophonic and phonemic phenomena in the isolate language Basque is presented. The focus is on speakers of the Biscayan dialect. First, Basque shows a spirantization process by which voiced plosives are produced as approximants, particularly intervocalically. Interestingly, we find that Basque /ld/ sequences, where spirantization is not expected [Hualde (1991) Basque Phonology], are realized as a lateral approximant followed by a voiced lateral fricative. Second, in this variety of Basque, the historical three-way contrast among sibilants (two alveolars and one postalveolar) has been reduced to a two-way distinction. The original contrast, still found in other varieties, between a laminal alveolar and an apical alveolar has merged with different results depending on the continuancy of the sibilants. Third, Basque presents a contrast between trill and flap intervocalically. However, elsewhere this is neutralized, and the precise realization of this segment varies from trill to frication. Finally, the Basque five-vowel inventory allows for almost any sequence of two vowels. The same vowel sequence might be a diphthong (tautosyllabic) or a hiatus (heterosyllabic) depending on the lexical item. That is, diphthongs and hiatus are contrastive. [Submitted for the student paper competition.]
Some issues concerning numerical simulation as a predictive tool for assessing sonar performance in uncertain environments
Authors: Finette Steven
Published: October 2013

One goal of numerical simulation in ocean acoustics is the accurate prediction of acoustic field properties in complex environments. In this context, the objective assessment of both sonar performance and associated signal-processing schemes operating within uncertain littoral environments pose significant challenges for numerical simulation. Some of the issues involved with using numerical models for the prediction of sonar performance in the presence of incomplete environmental information are addressed. To achieve credibility as a prediction tool, the simulation results should be held to the same standards as those associated with experimental results, i.e., the numerical predictions should include error bars or confidence intervals that represent a quantitative measure of the environmental uncertainty that is always present. Providing a rational, quantitative assessment of system uncertainty in complex environments is a nontrivial task. Incomplete environmental information occurs at multiple space-time scales within both the oceanographic and acoustic modeling phases; this uncertainty can propagate, interact, and amplify in the course of transmitting and processing the signal. It is argued that environmental uncertainty should be directly incorporated into the numerical simulation process so that it links directly to the physics of wave propagation. [Work supported by NRL Base funding through ONR.]