bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrasonic propagation modeling of orbital launch vehicles
Authors: Noble John M. , Alberts W. C. K. , Tenney Stephen M.
Published: May 2015

Over the last two years, NASA’s Wallops Flight Facility has been launching medium lift rockets for experimental and space station resupply missions. These launches have been a great opportunity to use the rocket-generated infrasound as a repeatable source to study the long range propagation over different seasons. For some of the launches during this period, two, 20-m arrays were deployed along different directions from the launch site. To increase the number of available sensors for comparison to three-dimensional propagation model results, data from the US Array was incorporated into the study. The US Array data significantly increased the range and azimuths used to compare the propagation modeling and measurement results. Calculated and measured transmission losses will be discussed.
Distortion-product otoacoustic emission fine structure as an indicator of combination-tone-mediated masking release
Authors: Lewis James D. , Clark Emily C. , Kopun Judy G. , Jesteadt Walt , Neely Stephen T. , Gorga Michael P.
Published: May 2015

During simultaneous masking, when the probe (fp) is higher in frequency than the masker (fm), the cubic difference tone (CDT; fcdt = 2fm-fp) can provide masking release. Given their shared origin, the 2f1-f2 distortion-product otoacoustic emission (DPOAE) may be a physiological correlate of CDT-mediated masking release [McFadden et al. (2012). J. Acoust. Soc. Am. 132, 968–983]. To test this hypothesis, masking release and DPOAEs were measured in normal-hearing listeners for 2 and 4 kHz probes. Probe threshold was measured in the presence of a masker (fp/fm = 1.2) and masker-suppressor pair. The suppressor was designed to mask detection of the CDT. Masking release was calculated as the change in masked-probe threshold resulting from presentation of the suppressor. DPOAEs were measured for an f2 (f2/f1 = 1.2) between 1.8 and 2 kHz (6-Hz intervals) and between 3.6 and 4.4 kHz (12-Hz intervals). Masking release was associated with DPOAE fine structure. Listeners without masking release lacked DPOAE fine structure. Fine structure was due to wave interference between distortion- and reflection-source components; the reflection-source component is thought to originate from the place of CDT detection. Findings suggest a similar underlying cochlear mechanism for the perceptual and acoustical effects. [Work supported by NIH-NIDCD grants 1F32DC014175-01A1, 5R01DC002251-18, 2R01DC008318-06A1, and 5P30DC004662-13.]
Can auditory brainstem and midbrain processing of interaural level difference cues really explain perceptual performance?
Authors: Cheung Stephanie T. , Bruce Ian C.
Published: May 2015

Neurons in the lateral superior olive (LSO) are believed to be involved in processing of interaural level difference (ILD) cues for sound localization. However, the ILD-tuning of LSO neurons varies with the absolute sound pressure levels (SPLs) at the two ears, in contrast to the relatively robust perceptual processing of ILD cues at different absolute SPLs. Tsai et al. (J. Neurophysiol. 2010) proposed that if some inferior colliculus (IC) neurons compute the difference between the contralateral and ipsilateral LSO outputs, the dependencies on absolute SPLs could be canceled out. However, they only considered pure-tone stimulation of single neurons at their characteristic frequencies and at relatively low SPLs. In this study, we evaluated the hypothesis of Tsai and colleagues using computational models of populations of auditory nerve, LSO and IC neurons consistent with Tsai and colleagues’ proposal. Predictions from two different neural decoder algorithms applied to LSO and IC model outputs indicate that discharge-rate saturation and spread of excitation in the auditory nerve lead to even greater SPL-dependence of ILD coding across a population of LSO neurons than is apparent in single neurons, and the IC differencing operation proposed by Tsai and colleagues does relatively little to ameliorate this problem.
No otoacoustic evidence for a peripheral basis underlying absolute pitch
Authors: Bergevin Christopher , McKetton Larissa , Stone Victoria , Grahn Jessica , Purcell David
Published: May 2015

Absolute pitch (AP) is the ability to identify or produce the perceived pitch of a sound (e.g., fundamental frequency of a piano note) without an external reference. This ability is relatively rare (~1/10,000 individuals possess it) and the mechanisms underlying AP are not well understood. This study examined whether there was evidence for a peripheral (i.e., cochlear) basis for AP based upon otoacoustic emissions (OAEs). The chief motivations were that both AP and spontaneous emissions (SOAEs) appear to have genetic components and anecdotal observations of prevalence in certain populations (e.g., relatively higher incidence of both in Asians). We examined SOAEs and stimulus-frequency emissions (SFOAEs) in both control (N = 21) and AP (N = 13) normal-hearing populations. We found no substantial differences in SOAE activity between groups (e.g., no evidence for one or more strong SOAEs that could act as a cue). SFOAE phase-gradient delays, measured using several probe levels (20–50 dB SPL), also showed no significant differences. This latter observation argues against sharper frequency selectivity in AP subjects. Taken together, these data support the prevailing view that AP mechanisms arise at a processing level in the central nervous system at the brainstem or higher (e.g., optimized neural coding).
Nonlinear dynamics of the organ of Corti, modeling both outer hair cell somatic motility and hair bundle motility
Authors: Nankali Amir , Sasmal Aritra , Grosh Karl
Published: May 2015

One of the principal questions in the cochlea biophysics is the determination of relative contributions of the two active processes, OHC somatic motility and HB motility, to the mechanics of the cochlea. Because of the difficulty of eliminating one mechanism without affecting the other, an unambiguous in vivo measurement differentiating their effects remains elusive. Theoretical models, therefore, have been used as one way to examine the contributions of the two active mechanisms to cochlear mechanics. In this paper, we use a physiologically based model of the mammalian organ of Corti to study the hearing active process and the relative contributions of these active forces. This local model integrates the electrical, acoustic, and mechanical elements of a cross section of the cochlea. The nonlinear dynamics of this model are studied with a special emphasis on the regions of stability and the amplification of the mechanical response arising from the active processes. [Work supported by NIH-NIDCD R01-04084 and NIH NIDCD-T32-000011.]
The cymbal as a structural acoustics demonstration: From evanescence to chaos
Authors: Gee Kent L. , Sommerfeldt Scott D. , Stout Trevor A. , Neilsen Tracianne B. , Aslani Pegah
Published: May 2015

The cymbal can be used as a rich structural acoustics demonstration. Many well-defined normal modes spanning a broad range of frequencies can be evaluated using various techniques, including Chladni patterns, speckle interferometry, Doppler vibrometry, and acoustical holography. The literature shows modal patterns that are both membrane-like with nodal lines and circles as well as more complicated, irregular shapes. When the cymbal is struck forcefully, orthogonality gives way to modal coupling and resulting chaotic vibration that produces the characteristic shimmering sound. The sound radiation favors high-frequency modes; however, when the cymbal is put close to the ear, low frequencies dominate the sound heard. This low-frequency ringing persists well after the rest of the sound has decayed. This auralized evanescence will be demonstrated and further described as part of the presentation.
Regional variation of vowels in Saterland Frisian
Authors: Schoormann Heike , Heeringa Wilbert , Peters Jörg
Published: May 2015

Saterland Frisian is spoken in three neighboring villages in North-West Germany, Strücklingen, Scharrel, and Ramsloh. In this study, we examine whether there is regional variation between the vowel systems of the three varieties. Speakers were instructed to read monophthongs and diphthongs in a neutral /hVt/ frame. Acoustic measurements included vowel duration, mid-vowel F1 and F2, the amount of Vowel Inherent Spectral Change (VISC, Nearey and Assmann, 1986), and the spectral rate of change (cf. Fox and Jacewicz, 2009). Results confirm large inventories for the three varieties of Saterland Frisian, although some vowels have undergone a merger with neighboring categories. The comparison of single vowel categories in the three varieties did neither reveal variation of vowel duration nor of dynamic spectral properties. Regarding static spectral properties, however, dialectal variation was observable. In Scharrel, monophthongs are more centralized in the F1 dimension. This finding is discussed with respect to the common view of local people that speakers from Scharrel speak faster than speakers from the other two places.
Vowels of Korean dialects
Authors: Kang Yoonjung , Schertz Jessamyn L. , Han Sungwoo
Published: May 2015

This study compares the monophthongal vowels /a ɛ e i ʌ ɨ o u/ of two North Korean dialects as spoken by ethnic Koreans in China (24 Phyeongan and 21 Hamkyoung) with the vowels of Seoul Korean (25 younger and 32 older). Younger and older speakers of Seoul Korean are compared to examine the sound change in progress in Seoul. The most striking difference among the dialects is in the realization of /o/ and /ʌ/. In Seoul, /o/ is produced higher than /ʌ/. In Phyeongan, /o/ is lower than /ʌ/, while in Hamkyoung, the two are comparable in height and the main contrast is along F2. Also, /e/-/ɛ/ contrast is lost in Seoul but robust in the Northern dialects. Within Seoul Korean, the back vowel shift observed in recent literature is confirmed (Cho S. 2003, Han J. and Kang H. 2013, and Kang Y. to appear)—/o/ is raised toward /u/ while /ɨ/ is fronted away from /u/ in younger speakers’ speech. In contrast to recent reports of /u/-/ɨ/ and /o/-/ʌ/ merger in homeland North Korean dialects (Kang S. 1996, 1997, Kwak 2003, and So 2010), in our Northern data, these contrasts remain distinct.
Production and perception among three competing pre-/l/ mergers
Authors: Arnold Lacey R.
Published: May 2015

This study examines the status of three patterns of merger among /ul/, /ol/, and /ʊl/ in Youngstown, Ohio. Using acoustic analyses of F1 and F2 and multiple-forced-choice perception task results from 40 Youngstown natives ages 9–81, this study addresses the progression of these mergers in apparent time, the perceptual correlates of merged and distinct production, and maintenance of durational distinctions in production and/or perception. Initial analysis of perception data suggests that different patterns of merger are progressing differently in the community and that production does not directly correlate with perception, perhaps as a result of exposure to multiple patterns of merger in the community. Despite the different patterns of merger in the community, speakers seem to pick up on durational cues in perception tasks.
Sensitivity to the emotional tone of verbal commands: Executive-function and chemotherapy effects
Authors: Espinoza-Varas Blas , Lakhwani Sudha , Khan Ashan , Ding Kai
Published: May 2015

Treatment adherence requires complying with verbal commands (“quit smoking!”) issued to impede or instigate behaviors, and a lenient or stern emotional voice tone (VT) calls for optional or mandatory adherence. The ability to identify the commands VT in conditions imposing executive-function (EF) demands could estimate the likelihood of achieving adherence. Prior to chemotherapy and between cycles 3–4 of gynecological cancer, we assessed VT identification under three EF demands. 1) Inhibitory control trials presented the cue word “left” or “right” followed by impeding commands in lenient or stern tone, mapped onto a left or right response; the cue and ear side could be congruent or in conflict with the correct response side. Trials presenting instigating commands (“go!”) mapped lenient or stern onto a right or left response. 2) Response-mapping switching conditions interleaved impeding and instigating commands within the same trial block, and required switching the mapping rule depending on the command, impeding or instigating. 3) Working-memory conditions asked whether the command presented on the current trial was equal to or different from the one presented two trials back. Without EF demands, VT identification errors were few, but increased significantly with EF demands, being largest in condition 2; chemotherapy effects were small.
Cross-modal transfer of talker learning
Authors: Simmons Dominique C. , Dias James W. , Dorsi Josh , Rosenblum Lawrence D.
Published: May 2015

Observers can match unfamiliar faces to corresponding voices (Kamachi et al., 2003). Observers can also use dynamic point-light displays containing isolated visible articulations to match faces to voices (Rosenblum et al., 2006) and to sinewave versions of those voices (Lachs & Pisoni, 2004) suggesting that isolated idiolectic information can support this skill. Cross-modal skills also extend to facilitation of speech perception. Familiarity with a talker in one modality can facilitate speech perception in another modality (Rosenblum, Miller, & Sanchez, 2007; Sanchez, Dias, & Rosenblum, 2013). Using point-light and sinewave techniques, we tested whether talker learning transfers across modalities. If learning of idiolectic talker information can transfer across modalities, observers should better learn to auditorily recognize talkers they have previously seen. Sixteen subjects trained to recognize five point-light talkers. Eight of these subjects then trained to recognize sinewave voices of the five previously seen talkers (Sheffert et al., 2002). The remaining subjects trained to recognize five sinewave voices of new talkers. Subjects trained to recognize voices of talkers who they had previously seen performed better than subjects trained to learn voices of new talkers, t(14)=−1.834, p<0.05. Results suggest that learning idiolectic talker-specific information can transfer across modalities to facilitate talker learning.
Exposure to an unfamiliar language bolsters talker learning
Authors: Orena Adriel John , Theodore Rachel M. , Polka Linda
Published: May 2015

Listeners are better at identifying talkers who speak their native language than talkers who speak a foreign language, showing that phonological knowledge of a language facilitates talker identification. However, research with infants indicates that language comprehension is not necessary for improving talker identification. In this study, we asked whether language exposure alone could improve talker learning. Two groups of English-monolingual adults were recruited: one group from Montréal, Québec, who receive regular French exposure, and the other from Storrs, Connecticut who receive no French exposure. In Experiment 1, we used a four-alternative forced choice task (4AFC) to train listeners about the voices of four English talkers and four French talkers. Results show that Montréal participants were faster at learning French voices than Storrs participants, showing that exposure to a foreign language is sufficient in boosting talker learning in that language. However, in Experiment 2, a 2AFC was used to train participants, and no significant differences were found between groups. These findings show that varying the training paradigm in laboratory analogs of talker identification can induce different types of talker learning. Taken together, our results suggest that phonological sensitivity contributes to listeners’ talker identification abilities, but only under certain training contexts.
Processing talker variability in semantic/associative priming: Does talker voice matter?
Authors: Zhang Yu , Lee Chao-Yang
Published: May 2015

The effect of talker variability on lexical access is investigated using short-term semantic/associative priming experiments. Prime-target pairs, either semantically associated (e.g., king-queen) or unrelated (e.g., bell-queen), were spoken by the same or different male speakers. Two interstimulus intervals (ISI, 50 and 250 ms) were used to explore the time course of semantic/associative priming and voice specificity effects. Forty listeners completed a lexical decision task followed by a talker voice discrimination task on the same auditory stimuli. Results from the lexical decision task showed semantic/associative priming effects, although the magnitude of priming was unaffected by talker variability or ISI. Results from the talker voice discrimination task showed no priming effects, although different-talker trials elicited faster and more accurate responses. In comparison with previous results using a similar paradigm (Lee & Zhang, in press; Zhang & Lee, 2011), this set of data suggests that talker variability might not influence access to semantic aspects of spoken language. Furthermore, voice discrimination task generated different patterns (e.g., lack of priming) from the lexical decision task. This suggests that the extent of talker voice effect on lexical access may be subject to attention manipulation.
Gender normalization in fricative perception in single- and mixed-gender blocks
Authors: Munson Benjamin
Published: May 2015

Previous research has shown that listeners’ identification of English anterior sibilant fricatives changes depending on whether they are primed to believe that the talker is a woman or a man, by pairing audio stimuli with images or videos of a woman or a man (Munson, 2011; Strand & Johnson, 1996; Winn et al., 2013). The current experiment is part of a program of research that endeavors to understand the nature of imputed gender effects in speech perception. Previous studies used fully within-subjects designs: listeners were presented with all stimuli combined with both male and female faces. The current experiment examined whether gender normalization occurs equally strongly in within-groups designs, and between-groups designs in which listeners are presented with only male or female faces. Four groups of listeners identified a nine-step sack-shack continuum created by combining a s-∫ continuum with a natural production of a VC that had been acoustically manipulated to be gender-neutral. Listeners were presented with a male face only, a female face only, both male and female faces in separate trials, or no face. Results will indicate how robust gender normalization effects are across different experimental conditions.
Talker variation and systematicity in voice onset time: A corpus study
Authors: Chodroff Eleanor , Wilson Colin
Published: May 2015

Previous research has demonstrated variation across talkers in the phonetic realization of speech sounds, including vowels (e.g., Peterson and Barney, 1952), fricatives (e.g., Newman et al., 2001) and stop consonants (e.g., Allen et al., 2003; Theodore et al., 2009). The challenge that talker variation presents to perceptual processes may be significantly reduced if different aspects of talker-specific phonetics are strongly correlated. The present study employs a subset of read speech from the Mixer-6 corpus (Brandschain et al., 2013), containing recordings from 129 native English participants (60 male). The voice onset time (VOT) of prevocalic word-initial stops (N = 59,075) was measured using forced alignment (Yuan & Liberman, 2008) and subphonemic postprocessing (AutoVOT; Sonderegger & Keshet, 2012). Talker means of the voiceless stops are highly correlated with each other (rs = /p/-/t/: 0.76; /p/-/k/: 0.79; /t/-/k/: 0.74; ps < 0.0006, alpha-corrected), as are /b/ and /g/ among the voiced stops (r = 0.49, p < 0.0006). Additionally, talker means of each stop category are correlated with corresponding standard deviations (r = 0.87, p < 0.0001). These suggest a degree of systematicity in variation, with implications for talker adaptation, as listeners may extrapolate from few input values to approximate talker-specific variance and cross-category means.
Examining correlations between phonetic parameters: Implications for forensic speaker comparison
Authors: Gold Erica , Hughes Vincent
Published: May 2015

The research presented in this paper builds upon a previous pilot study (Gold and Hughes 2012). This paper explores the correlation structure of speech parameters from a sociolinguistically homogeneous set of male speakers of Southern Standard British English using a series of segmental, suprasegmental and linguistic parameters. Data was extracted from a subset of speakers from the Dynamic Variability in Speech (DyViS) database (Nolan et al., 2009) and consist of: midpoint F1, F2 & F3 values for /a ɔ u/, midpoint F1, F2 & F3 values hesitation markers UM and UH, dynamic F1, F2 & F3 values for PRICE /aɪ/, long-term formant distributions (LTFD) F1-F4, mean and standard deviation of fundamental frequency (F0), mean articulation rate (AR), voice onset time (VOT) for word-initial /t/ and /k/, and click rate (ingressive velaric stops). The results of the study present a complex correlation structure between linguistic-phonetic variables, and not all correlations are predicted by phonetic theory. The results of the correlations are discussed in relation to implications that exist when combining parameters for forensic speaker comparison casework; specifically, the caution that needs to be yielded by experts in casework to avoid over- or under-estimating the strength of evidence.
Three-dimensional parabolic-equation solutions with boundary-fitted grids
Authors: Lin Ying-Tsong
Published: May 2015

A higher-order operator splitting method incorporating multi-dimensional cross terms has recently been proposed to solve the three-dimensional (3D) parabolic wave equation consisting of a square-root Helmholtz operator. The advantages of this splitting method include providing a more accurate 3D parabolic-equation (PE) approximation, as well as supporting fast marching solvers, such as the Alternating Direction Implicit (ADI) Padé method. To apply this numerical solution scheme to a 3D underwater acoustic waveguide with surface waves in a boundary-fitted model grid, one can employ a one-dimensional (1D) non-uniform discretization formula derived from Galerkin’s method using asymmetric basis functions [W.M. Sanders and M.D. Collins, J. Acoust. Soc. Am. 133, 1953–1958 (2013)]. The use of this discretization formula is to approximate the two alternating sets of 1D differential equations with respect to either one of the two transverse directions at the ADI marching steps. An idealized semi-circular waveguide problem with a closed-form solution is considered as a benchmark to test different 3D PE solutions. Compared to the fixed grid PE solution, the boundary-fitted PE solution is an order of magnitude more accurate in terms of both the magnitude error per unit distance and the relative phase error. [Work supported by the ONR.]
Three-dimensional noise modeling in a submarine canyon
Authors: Barclay David R. , Lin Ying-Tsong
Published: May 2015

The ambient sound field due to wind generate surface noise in an idealized Gaussian submarine canyon can be described using the method of normal mode decomposition applied to a three-dimensional longitudinally invariant wave-guide. The modal decomposition is carried out in the vertical and across-canyon horizontal directions and gives a semi-analytical solution describing the three-dimensional topographic effects on the spatial distribution of the noise, the power spectrum, and the vertical and horizontal coherences. Additionally, the noise field can be computed using wave-equation reciprocity and either a three-dimensional cylindrical co-ordinates parabolic equation (PE) or an Nx2D PE sound propagation model. Inter-comparison of these models highlights the effect of the three-dimensional topography on the vertical coherence and mean-noise level as a function of arrival direction relative to the canyon’s axis. These effects include the focusing of noise along the canyon axis and the frequency perturbation of vertical coherence minima.
Toward monodisperse ultrasound-triggered phase-shift emulsions using differential centrifugation
Authors: Stewart Kyle , Radhakrishnan Kirthi , Haworth Kevin J.
Published: May 2015

Acoustic droplet vaporization (ADV) is a process that enables the in situ production of microbubbles from an injected perfluorocarbon emulsion and it has been investigated for imaging and therapeutic applications. High-speed mechanical shaking rapidly produces a polydisperse emulsion (~1010 droplets/mL) with droplets ranging from less than 400 nm to greater than 15 μm. The ADV pressure amplitude threshold is higher and fraction of transitioned droplets lower for droplets smaller than approximately 2 μm in diameter. Droplets greater than approximately 8 μm in diameter are not suitable for systemic administration. Therefore, high-speed mechanical shaking produces many droplets of limited utility. Differential centrifugation has been used as a size isolation technique for polydisperse ultrasound contrast agents. By applying a similar technique to a perfluorocarbon emulsion, the volume-weighted fraction of droplets between 2 and 5 μm was increased from 29±2% to 93±3%. The transition efficiency of the droplets between 2and 5 μm was the same regardless of whether a polydisperse or monodisperse distribution was insonfied with 2 MHz ultrasound. The ADV pressure threshold of differentially centrifuged droplets was similar to non-centrifuged droplets. [Supported in part by NIH grant KL2 TR000078.]
On the use of local speckle field as a correction factor for shear modulus estimates based on multiple-track-locations methods
Authors: Osapoetra Laurentius O. , Langdon Jonathan H. , McAleavey Stephen A.
Published: May 2015

Acoustic-radiation-force impulse (ARFI) imaging for characterization of shear modulus of biological tissues employs either multiple-track-locations (MTL) methods or single-track-location (STL) methods. MTL estimates of shear modulus at different depths suffer from more variability compared to those of STL estimates. Our studies have shown a significant correlation between bias in shear-wave arrival time estimates and local speckle field lateral statistics. We propose using the local speckle field as a surrogate for the unknown bias apparent in MTL shear-wave speed estimates. This local speckle field is determined using a “swept-receive acquisition” that is produced by holding the transmit beam fixed while laterally translating the receive aperture. Application of various lateral weighting functions to the swept-receive image results in an approximate compensation to the tracking bias. In this study, we implement our technique on simulation and experimental data from gelatin phantoms. Additionally, the effect of varying transmit-receive aperture f/# on the accuracy of our compensation method is investigated in simulation. Finally, the quality of compensated MTL shear modulus images are quantified and compared to those of the uncompensated MTL and of STL methods in matched tissue mimicking phantom experiments.
Iterative reconstruction of the ultrasound attenuation coefficient from backscattered signals
Authors: Ilyina Natalia , Hermans Jeroen , Verboven Erik , Van Den Abeele Koen , D'Agostino Emiliano , D'hooge Jan
Published: May 2015

Estimation of the local acoustic attenuation from backscattered signals has several clinical applications but remains an open problem. Most of the proposed solutions relate the observed spectral changes directly to the theoretical predictions. However, these methods make a number of approximations and require correction strategies for acoustic wave phenomena that are not accounted for in the model (e.g., non-linearity). In this study, attenuation was estimated by successively solving the forward wave propagation problem for different attenuation coefficients and by matching the calculated backscattered signals to the observed one. For the forward problem, the effects of attenuation, nonlinear distortion, reflection and scattering were taken into account. The proposed approach was validated on simulated data and data recorded in six tissue mimicking phantoms and was compared to conventional methods. The relative error of the attenuation coefficient remained below 10% for the simulated and phantom data. The conventional methods showed a comparable performance on the simulated data, but their error significantly increased in the phantom study. The proposed method outperformed state-of-the-art attenuation estimators. Moreover, it can be used to estimate local non-linearity. In future work, the propagation model will be extended to 3D and diffraction effects will be included.
Understanding timbral effects of multi-resonator/generator systems of wind instruments in the context of western and non-western music
Authors: Braasch Jonas
Published: May 2015

Wind instruments are often modeled as a coupled generator-resonator system, which in case of the clarinet consists of a reed and a cylindrical pipe. However, the fact that the throat and oral cavities behind the tone generator also play a critical role is often neglected. While the resonance pipe of a wind instrument can be adjusted in length through keyholes or valves, its width is fixed. The opposite can be observed for the human resonance system where the length is fixed but the dimensions of the cross-section are variable. This is important fact is routinely used to shape the timbral qualities of tones and to determine the tones’ fundamental frequencies—for example, to generate high notes above the normal range on a saxophone. In many music cultures, time-varying timbral modifications are more important than melodic aspects, for example, in traditional digeridoo practice. A third resonator system is the room the musical instrument is performed in. This can also have important timbre shaping aspects, emphasizing, for example, the brilliant sound of Bach trumpets. An extended saxophone [Braasch, 2014, J. Acoust. Soc. Am. 135, 2245] and convolution reverb is used to demonstrate and analyze the effects of multi-resonator/generator systems for this presentation.
The origins of building acoustics for theater and music performances
Authors: Mourjopoulos John
Published: May 2015

The ancient Greek amphitheaters and roofed odeia represent the earliest examples of acoustics utilized for enhancing theatrical and music performances over large public audiences, often up to 15,000 participants. Such an early achievement, more than 2000 years ago, was possibly crucial for the foundation of these performance-based art forms within the ancient Greek society and the eventual geographical spread of these buildings. Through the continuous evolution during the Roman era, via the Renaissance theaters and the modern concert halls, these specially constructed spaces allowed the performance-based art forms to be sustained and evolve as essential constituents of the western cultural heritage and civilization. We shall first consider some historical and architectural properties of these early performance spaces and then summarize their design principles and acoustic parameters. Acoustic properties were different for spaces used for theatrical and music performances: open-air theaters for drama were manly utilizing early reflections (e.g., up to 40 ms) to achieve perfect speech intelligibility for listener distances even beyond 60 m; in contrast, roofed-odeia had acoustics appropriate for music with prominent reverberation comparable to that of modern concert halls. The presentation will include auralization demos for important ancient theaters and odeia.
Conch-shells, bells, and gongs in Hindu temples
Authors: Prasad Marehalli
Published: May 2015

Acoustics plays an important role in Hinduism and Hindu temples and worship practices. Several instruments such as conch-shells, bells, and gongs due to their musical qualities are used to enhance the spiritual experience of devotees in Hindu temples. These instruments are used to augment the acoustically rich Vedic chanting and singing. These instruments are generally used in a room called Ardha Mantapa (in Sanskrit), which is coupled to the Sanctum Sanctorum (called as Garbha Griha in Sanskrit) in a Hindu temple. The Garbha Griha and the Ardha Mantapa play an important role in the acoustical environment in the temples. These instruments are used both individually as well as collectively during the worship. These instruments through their tonal quality complement the soundscape of the environment. This presentation deals with spectral measurements of these instruments and also the acoustical aspects of the temple space. Measurements taken in two Hindu temples will be presented.
Traditional and recent performance practice in Asian free reed mouth organs: The sheng and khaen as case studies
Authors: Cottingham James P.
Published: May 2015

Mouth-blown instruments employing a free reed coupled to a pipe resonator have long been used throughout East and Southeast Asia. Details of the origin and development of these instruments are not known, but are closely connected with the history and prehistory of a multitude of ethnic groups. Beginning from presumed folk instrument origins, the free reed mouth organs have been used in a variety of contexts including simple signaling, courtship, local entertainment, civic or military processions, and sophisticated court music. Two instruments operating on similar acoustical principles have had contrasting histories: the Chinese sheng and the Laotian khaen. The sheng has a two thousand year recorded history in China, and in the last century modernized versions have been developed and appeared in the Western concert hall style setting of the Chinese orchestra. The khaen, while remaining a strong cultural symbol of the Lao people, has not undergone similar developments as once prevalent traditional performance styles have almost disappeared.
Outdoor oratory and performance space
Authors: Boren Braxton B.
Published: May 2015

Spoken sermons and oratory in the West have usually been confined to the interior of churches or parliaments that bear similarities to traditional concert halls. However, the largest crowds in history are described as being outside due to the size constraints of most interior spaces. Historical estimates of crowd sizes or the intelligible range of speakers have generally been quite speculative. However, recent work has used an acoustical experiment by Benjamin Franklin to estimate the 1 m on-axis average SPL of the Anglican preacher George Whitefield at 90 dBA. Computational simulation of Whitefield’s preaching in London confirms Franklin’s estimate that he could have been heard by crowds of 30,000 or more depending on weather conditions and crowd noise. Using Whitefield as a benchmark, other historical orations may be evaluated based on geometric and acoustic factors. Within this framework, speeches given by Pericles, Demosthenes, Alexander the Great, and Julius Caesar are examined based on the size and noise of the crowd as well as the level attainable by each speaker. In each case, outdoor oratory possesses unique performance considerations distinct from interior or musical settings.
Lou Sutherland—Bridging acoustics and people in acoustics
Authors: Schulte-Fortkamp Brigitte
Published: May 2015

Lou Sutherland’s scientific contributions have helped to renew the acoustic world. In all the years of my participation at ASA meetings, Lou has provided valuable insights that have advanced many subfields of noise. These include aircraft noise reduction, atmospheric sound propagation, classroom learning, and soundscape. Lou is always open to new ideas to improve acoustical calculations and measurements. His extensive work in classroom acoustics with David Lubman has increased his prominence in noise and architectural acoustics. For example, classroom acoustics has become one of the most persistent topics on the agendas of the Technical Committees on Noise and Architectural Acoustics for at least a decade. Although Lou and I have never worked together his publications on aircraft noise and soundscape have strongly influenced my research. Lou has an endearing and effective way of “inducting” new people into the ASA world. I remember with gratitude how Lou stimulated me to become active in ASA’s Noise and Architecture Acoustics communities by introducing me to its distinguished members. I am very pleased for this opportunity to thank Lou for his past work. And to continue our valuable discussions that make the world a better place by reducing noise and improving soundscape.
Action verb processing correlates with motor asymmetry in Parkinson's disease
Authors: Wang Emily , Walters Lee K. , Verhagen Metman Leo A.
Published: May 2015

Onset of motor symptoms in PD is asymmetrical, and symptoms affect the side of onset more severely throughout the progression of the disease, which is known as “motor asymmetry.” Previous studies revealed that PD patients with right-motor asymmetry (more severe symptoms on the right side of body) exhibited more speech impairment than those with left-motor asymmetry (Wang et al., 2003; 2006). Patients with active deep brain stimulation (DBS) exhibited more severe speech deficits when they received either bilateral or left-only stimulation of the subthalamic nucleus (STN) than receiving right-only STN stimulation (Santens et al., 2003). These findings lead to the current hypothesis that there is correlation between the motor asymmetry and linguistic processing of action verbs. Using a novel action verbal processing paradigm, 24 PD patients (12 right- and 12 left-motor asymmetry) and 11 age- gender-matched healthy controls were tested. The results showed that when the motor asymmetry was sufficiently different, i.e., when the difference of the UPDRS scores between the two sides of the body is greater than 2 (points), the right-motor asymmetry patients took longer to process the action verbs, supporting the hypothesis that motor asymmetry is correlated with linguistic processing of action verbs at the cortical level.
Syllable position effects on perceptual determination of /r/ errors in expert and naive listeners
Authors: Hamilton Sarah M. , Ishikawa Keiko , Hashemi Hosseinabad Hedieh , Boyce Suzanne , Mullins Lindsay
Published: May 2015

When ordinary listeners hear words containing a phoneme whose production differs in one feature from the target, the anomaly is often ignored if the word is recognizable. Phonetic research and clinical practice both depend on phonetics training to mitigate these top-down listening effects and enable detection of anomalies. Children with speech sound errors for American English /r/ are believed to have better productions when /r/ occurs at the beginning of a word. However, the shorter duration of /r/ word-initially may be leading clinicians to under-identify errors. While previous studies have shown that clinicians are better than naive listeners at identifying error /r/ in single syllables, they have not assessed identification of /r/ errors in whole words, where position may interact with lexical bias effects. In this study, speech-language pathologists and naive listeners rated children’s natural speech productions of word-initial and word-final/r/ in whole words. These /r/ productions in words were selected to make a continuum defined by normalized third formant values. Reaction times and responses to stimuli were compared between listener groups. Initial results indicate that clinicians and naive listeners differ in their responses to formant profiles of stimuli, but that syllable position exerts a strong effect for both groups.
The use of visual information in non-native speech sound discrimination across the first year of life
Authors: Danielson D. Kyle , Kandhadai Padmapriya A. , Werker Janet F.
Published: May 2015

Infants are able to match seen and heard speech even in non-native languages, and familiarization to audiovisual speech appears to affect subsequent auditory-only discrimination of non-native speech sounds (Danielson et al., 2013; 2014). However, the robustness of these behaviors appears to change rapidly within the first year of life. In this current set of studies, conducted with six-, nine-, and 10-month-old English-learning infants, we examine the developmental trajectory of audiovisual speech perception of non-native speech sounds. In the first place, we show that the tendency to detect a mismatch between heard and seen speech sounds in a non-native language changes across this short period in development, in tandem with the trajectory of auditory perceptual narrowing (Werker & Tees, 1984; Kuhl et al., 1992; inter alia). Furthermore, we demonstrate that infants’ familiarization to matching and mismatching audiovisual speech affects their auditory speech perception differently at various ages. While six-month-old infants’ auditory speech perception appears to be malleable in the face of prior audiovisual familiarization, this tendency declines with age. The current set of studies is one of the first to utilize traditional looking-time measurements while also employing pupillometry as a correlate of infants’ acoustic change detection (Hochmann & Papeo, 2014).
Segmental interference by the masker modulation spectrum in sentences: Effects of age and hearing loss
Authors: Fogerty Daniel , Ahlstrom Jayne B. , Bologna William J. , Dubno Judy R.
Published: May 2015

Younger normal-hearing, older normal-hearing, and older hearing-impaired subjects listened to sentences with consonants or vowels replaced with noise modulated by the envelope of a competing talker. The modulation spectrum of the noise was low-pass filtered at different cutoff frequencies. Sentences were spectrally shaped according to listeners’ individual audiometric thresholds to ensure sufficient audibility; in addition, a second group of younger normal-hearing subjects listened to sentences that were spectrally shaped according to the mean audiogram of the hearing-impaired subjects. Results demonstrated declines in sentence intelligibility for older as compared to younger listeners, with more evident declines for older hearing-impaired listeners. Declines in sentence intelligibility based on vowel cues with increasing modulation rates in the competing noise were noted for all listener groups. In contrast, sentence intelligibility based on consonant cues increased when the competing noise included modulation rates between 8 and 16 Hz. An adverse effect of spectral shaping was also observed, with an overall decrease in performance for younger spectrally matched listeners. Thus, in temporally complex listening conditions, spectral shaping to assure audibility may not fully control for reduced sentence intelligibility among hearing-impaired listeners and may interact with temporal properties of the speech signal. [Work supported by NIH/NIDCD and ASHA.]
Phonemic restoration with envelope and periodicity cues: Effects of age and competing talkers
Authors: Bologna William J. , Chatterjee Monita , Dubno Judy R.
Published: May 2015

Perception of interrupted speech improves when noise is inserted in silent gaps between speech segments. This “phonemic restoration” is enhanced with intervening noise that contains low-level speech information, such as noise modulated by the temporal envelope of the missing speech. However, this benefit may be reduced in multiple-talker environments where competing speech contributes additional masking effects. To minimize these masking effects, periodicity information within intervening noise segments of interrupted speech may help listeners segregate multiple voices and thus increase phonemic restoration. The relative benefit of envelope and periodicity cues, and their use by older adults with poorer performance in multiple-talker environments, remains unclear. To address these questions, younger and older adults with normal hearing listened to target sentences in quiet and competing talker backgrounds; target sentences were periodically interrupted with silence, envelope-modulated noise, or pulse trains, which contained periodicity information from the missing speech. Phonemic restoration was defined as the difference in recognition of interrupted sentences filled with envelope-modulated noise or pulse trains as compared to sentences interrupted by silence. Results are discussed in terms of contributions of envelope and periodicity cues to perceptual organization in complex listening environments. [Work supported by NIH/NIDCD and a AAA Student Investigator Research Grant.]
Across-formant integration and speech intelligibility: Effects of acoustic source properties in the presence and absence of a contralateral interferer
Authors: Summers Robert J. , Roberts Brian , Bailey Peter J.
Published: May 2015

Three experiments used three-formant (F1 + F2 + F3) analogues of natural sentences to explore the role of acoustic source properties in across-formant integration. In experiment 1, F1 + F3 were generated using a monotonous periodic source (F0 = 140 Hz) and second-order resonators (H1 + H3); in experiment 2, F1 + F3 were tonal analogues (T1 + T3). F2 could take either form (H2 or T2). Target formants were always presented monaurally; the target ear was assigned randomly on each trial. In some conditions, only the target was present; in others, a competitor for F2 (F2C) was added contralaterally. Listeners must reject F2C to optimize recognition. Competitors (H2C or T2C) were created using the time-reversed frequency and amplitude contours of F2. Without F2C, intelligibility was reasonably high and the effect of a source mismatch between F1 + F3 and F2 was negligible. For both shared- and hybrid-source targets, the impact of adding F2C was modest when it was tonal but large when it was harmonic, irrespective of whether F2C matched F1 + F3. Experiment 3 showed that this pattern was maintained when corresponding harmonic and tonal analogues were loudness-matched. These findings extend those from earlier research using dichotic targets. Source type and competition, rather than acoustic similarity, govern the phonetic contribution of a formant. [Work supported by ESRC.]
Classification of signals in spherically invariant random clutter
Authors: Newhall Bruce K. , Slowikowski Anna
Published: May 2015

The generalized likelihood ratio test (GLRT) is derived for the case of a signal subspace in acoustic clutter characterized by a spherically invariant random variable (SIRV). This result is a generalization of two previous results. First, the GLRT for the detection of a one dimensional signal in SIRV clutter has been previously given. However, featureless classification work has previously considered signals that are members of a multidimensional subspace but only in Gaussian clutter. The SIRV model extends that to the non-Gaussian clutter case. A SIRV is the product of two random variables: a non-Gaussian scalar times a complex multivariate Gaussian vector. The general GLRT result is then applied to a generalized gamma distribution for the SIRV scalar. When the generalized gamma exponent parameter is −2 this produces a product SIRV whose acoustic intensity has a generalized Pareto distribution. When the exponent parameter is + 2, the SIRV intensity is k distributed. This demonstrates that two widely used clutter distribution models are special cases of this more general distribution. Methods of parameter estimation for application of the technique are also given. [Work supported by the Office of Naval Research.]