bluuebunny/crossref_metadata_2025 huggingface dataset:
Whistly fricatives: MRI and acoustic data
Authors: Shadle Christine H. , Proctor Michael , Iskarous Khalil
Published: October 2013

Nonlinear effects in airflow during fricative production can lead to a whistly acoustic quality, which is used contrastively in a few languages and can occur due to dental appliances, but also often occurs in fluent speech. In a magnetic resonance imaging (MRI) study of American English fricatives produced by five subjects, it was noted that some of the subjects produced whistly fricatives. Articulatory and acoustic analyses will be presented to argue that small articulatory changes can produce significantly different acoustic results within the same segment class for a single subject. Lip rounding and presence of a sublingual cavity can contribute to whistling, but a single subject can produce whistly or normal frication if either of these factors is present or absent. Possibly different whistle mechanisms (edge versus hole tone) could account for some of these seeming anomalies. Strident fricatives are therefore an example of a class of speech sounds where small articulatory differences can lead to significant acoustic differences. [Research supported by NIH Grant No. NIDCD R01 DC 006705.]
A motor differentiation model for liquid substitutions in children’s speech
Authors: Gick Bryan
Published: October 2013

Studies of lip-jaw coordination in children have shown a lack of motor differentiation between anatomically coupled articulators in young childrens speech [Green & al. 2000, JSLHR 43: 239–255]. A model is described in which children contending with their developing motor systems generally strive to reduce the degrees of freedom of complex anatomical structures (e.g., the tongue). The claim is pursued that segmental substitutions (e.g., /w/ replacing /r/ or /l/) are the result of specific compensation strategies which aim to simplify the complexity of the articulatory task. The proposal that gestural simplification may dictate substitution strategies for liquid consonants has been suggested previously [Studdert-Kennedy & Goldstein 2003, Language Evolution, Oxford U. Pr. 235-254]. It is proposed here that gestural simplification may be achieved via one of two basic mechanisms: gestural omission and stiffening (and hence merger), and that these two mechanisms account for all of the commonly attested substitutions for English /r/ and /l/. Supporting data are presented from ultrasound studies of: postvocalic /r/ production of an 11-month-old female speaker of English, liquid production of a group of 3–5-year-old speakers of English, and liquid production and substitutions in the speech of adolescent speakers of English with speech and hearing disorders.
Acoustic cues of ‘‘retroflex’’ and ‘‘bunched’’ American English rhotic sound
Authors: Zhou Xinhui , Espy-Wilson Carol , Tiede Mark , Boyce Suzanne
Published: October 2013

The North American rhotic liquid has two well-known and maximally distinct articulatory variants, the classic retroflex tongue posture and the classic bunched tongue posture. The evidence for acoustic difference between them is reexamined using magnetic resonance images of the vocal tracts from two similar-sized subjects with different tongue postures of sustained /r/. Three-dimensional finite element analysis is performed to investigate the acoustic wave propagation property inside the vocal tract, the acoustic response, and the area function extraction based on pressure isosurfaces. Sensitivity functions are studied for formant-cavity affiliation. It is revealed that these two variants have similar patterns of F1–F3 and zero frequency. However, the retroflex variant is predicted to have a larger difference between F4 and F5 than the bunched one (1400 Hz versus 700 Hz). This difference can be explained by the geometric differences between them, in particular, the shorter, narrower, and more forward palatal constriction of the retroflex variant. In addition, the predicted formant pattern is confirmed by measurement from acoustic data of sustained /r/ and /r/ in nonsense words from several additional subjects. These results may prove to be useful to researchers in speech motor control, speech pathology, speaker verification, speech recognition, and speech synthesis. [Research supported by NIH.]
Talker-specific contextual influences on voice-onset-time
Authors: Theodore Rachel M. , Miller Joanne L. , DeSteno David
Published: October 2013

Research has shown robust contextual influences on voice-onset-time (VOT) in speech production. The current work examines talker-specificity for two such cases: speaking rate (VOT increases as syllable duration increases) and place of articulation (VOT increases as place moves from anterior to posterior position). Tokens of /pi/ (labial) and /ki/ (velar) were elicited from talkers across a range of rates. VOT and syllable duration were measured for each token. For each talker, separate labial and velar linear functions relating VOT to syllable duration were calculated. Ongoing analyses indicate that (1) for both the labial and velar functions there is significant variability across talkers’ slopes [see also Theodore et al., J. Acoust. Soc. Am. 120, 3293 (2006)], but there is no significant variability in the difference between labial and velar slopes for a given talker. Thus the effect of speaking rate is talker-specific, and stable across place of articulation. (2) For each talker, the velar intercept is located at a longer VOT than the labial intercept, with significant variability in the magnitude of displacement across talkers. Thus the effect of place is also talker specific. These findings support the view that phonetic properties of speech include talker-specific contextual influences. [Work supported by NIH/NIDCD.]
Consonant duration and vowel-to-vowel coarticulation in Japanese
Authors: Lofqvist Anders
Published: October 2013

This study examined vowel-to-vowel coarticulation in sequences of vowel-bilabial consonant-vowel, where the duration of the oral closure for the consonant is varied for linguistic purposes. Native speakers of Japanese served as subjects. The linguistic material consisted of Japanese word pairs that only differed in the duration of the labial consonant, which was either long or short; the durational ratio of short and long consonants in Japanese is about 1:2. Recordings were made of lip and tongue movements using a magnetometer system. It was hypothesized that there would be greater vowel-to-vowel coarticulation in the context of a short consonant, since a long consonant would allow the tongue more time to move. The results do not show any strong support for this hypothesis, however. The reason is that Japanese speakers modulate the speed of the tongue movement between the two vowels according to consonant duration, making it faster during a short consonant and slower during a long consonant. [Work supported by NIH.]
Acoustic correlates of emphatic consonants in Arabic
Authors: Jongman Allard , Herd Wendy , Al-Masri Mohammad
Published: October 2013

Emphasis is a distinctive feature of Semitic languages such as Arabic that refers to a group of consonants produced with a secondary constriction in the posterior vocal tract and a primary constriction typically in the dental/alveolar region. Initial findings of a detailed acoustic investigation of emphasis in Urban Jordanian Arabic will be presented. Eight adult speakers of Urban Jordanian Arabic (four males and four females) produced a list of minimal pairs of emphatic versus plain CVC words. The list consisted of four UJA consonant pairs:/d/,/dbackglotstop/,/t/, /tbackglotstop/,/■/, /■backglotstop/, and /s/, /sbackglotstop/, along with the six vowels of UJA (long and short /i/, /a/, and /u/. Each target consonant occurred in both word−initial and word−final position. Results show consistently higher F1 and F3 values and lower F2 values for vowels in emphatic consonantal environments compared to vowels in plain environments. In addition, emphatic consonants have a lower spectral mean than their plain counterparts. Results from bisyllabic words will also be presented to evaluate the direction and extent of the spread of emphasis within the word. [Research supported by NSF.]
A preliminary investigation of voice onset time associated with Turkish stops
Authors: Sadaka Janine , Ng Manwa L.
Published: October 2013

Voice onset time (VOT) refers to the timing between the release of a stop and the onset of the following vowel. Aspiration directly reflects the period of voicelessness following a stop release. Both VOT and aspiration are temporal measurements that are results of coordinated articulatory action. The present study will attempt to determine the relationship between VOT and aspiration, and VOT and voicelessness of Turkish stops. Comparison will also be made with those reported for English. Voicing differentiation in stops requires complex motor control. Thus, many speech disorders are associated with distorted VOT. Results will be used to develop a norm on VOT for Turkish stops. This will assist in evaluating speech disorders in Turkish-speaking individuals that involve motor control problems.
The effects of morphological boundaries and speech rate on geminate closures in Turkish
Authors: Babel Molly , Pycha Anne
Published: October 2013

In Turkish, geminate consonants can occur in a word root and in derived positions across morphemes. In this experiment we explore closure duration and VOT in geminate consonants within roots, across root-suffix boundaries, suffix-suffix boundaries, and novel compound boundaries. Five (3=male, 2=female) native speakers of Turkish were recorded producing 80 target and 20 filler words with an equal number of [tt], [kk], [ll], and [mm] geminates in the four different morphological contexts named above. Subjects were instructed to produce each word in a carrier phrase three times. The wordlist was read twice by each talker. The first time subjects were asked to read at a slow, comfortable pace. The second time through, the list subjects were instructed to speak as quickly as possible without making mistakes. Consonant closure duration will be measured for the geminates. The voice onset time associated with [tt] and [kk] closures will also be measured. The results of the investigation have implications for theoretic phonological accounts of geminates.
Particle filtering for dispersion curve estimation from spectrograms of acoustic signals
Authors: Zorych Ivan , Michalopoulou Zoi-Heleni , Miller James H. , Potty Gopu R.
Published: October 2013

In this work we develop a particle filtering method for dispersion curve extraction from spectrograms of acoustic signals, the goal being to obtain accurate representation of modal dispersion for geoacoustic inversion. The approach combines particle filtering with modeling of sound propagation in ocean environments to track dispersion curves of multimodal signals in noisy environments. ‘‘Crispy’’ estimates of dispersion curves are extracted that are not characterized by extensive uncertainty typically hindering geoacoustic inversion. Results are presented from both synthetic signals and real data collected in the East China Sea during the ASIAEX experiment. [Work supported by ONR.]
Sampling with heuristics
Authors: Knuth Kevin H.
Published: October 2013

Algorithms that rely on heuristics are attractive to those interested in solving acoustic problems. The main reason is that heuristics often derive from solutions to a simplified problem and, as such, they are able to accurately estimate a subset of model parameters. However, algorithms that rely on heuristics are not sufficiently robust as they ignore vast regions of the parameter space. For this reason, sampling techniques that focus on exploration increase the probability of finding a difficult solution. However, sampling algorithms can become trapped in difficult problems that possess vast plateaus in the parameter space upon which the solution space occupies an extremely small volume. In these cases, heuristics at least have a chance to succeed where sampling is likely to fail. This work considers incorporating heuristically-obtained samples into a relatively new sampling algorithm called nested sampling. Nested sampling strives to localize the solution space while simultaneously integrating the posterior probability to compute the Bayesian evidence. The challenge is that nested sampling accomplishes this by working with uniformly distributed samples, whereas heuristics necessarily result in nonuniformly distributed samples. The difficulties and benefits in combining these two search strategies are described in the context of acoustic source separation.
Application of multitaper methods to passive sonar
Authors: Wage Kathleen
Published: October 2013

While the multitaper spectral estimation method [Thomson, Proc. IEEE 70, 1055–1096 (1982)] is used extensively in time series analysis, it has received much less attention in the array processing literature. The multitaper approach reduces the variance of power estimates by averaging windowed Fourier transforms of the data obtained using a set of orthogonal window functions. One advantage of the multitaper method is that it is designed to work with low sample support. Since multitaper estimates are often formed using a single data snapshot, they are suitable for use in highly nonstationary environments where it is difficult to obtain reliable estimates of the noise and interference statistics. This talk focuses on the application of the multitaper method to the passive sonar array processing problem. Standard techniques exist for detecting the presence of line components using multitaper estimates. This talk describes how to extend these techniques to detect plane waves in sonar data, where the signals are typically modeled as complex Gaussian rather than deterministic. Processing of non-plane-wave signals, e.g., normal modes, will also be briefly discussed. [Work supported by an ONR Young Investigator Award.]
Active target tracking using the bistatic invariance principle
Authors: Zurk Lisa , He Chensong
Published: October 2013

The acoustic pressure received from a moving source in a shallow water channel is highly variable and depends critically on characteristics of the channel such as bathymetry, sound speed, and bottom properties. Past work has shown that knowledge of the channel properties can be embedded in physics-based signal processing algorithms for increased system performance. However, this requires accurate knowledge of the channel characteristics, which are often poorly known. An alternate approach is to identify aspects of the field structure that are invariant to small perturbations in the propagation environment. The waveguide invariant is a scalar parameter that has been used extensively in passive sonar to interpret features such as intensity maxima in lofargrams. Recent work has used experimental data to demonstrate that a similar parameter exists for active geometries, although the invariant relationship is more complicated because of the multiple propagation paths. In this presentation active invariant striations are exploited in an active tracker formulation. The tracker utilizes a state space representation that includes the time-dependent frequency content of the pulse as one of the sonar observables. In addition to target kinetics, the time-frequency structure provides track constraints that improve discrimination of target versus bottom reverberation. [Work sponsored by ONR-321US.]
60 MHz multidomain ultrasonic transducer
Authors: Ostrovskii Igor V. , Nadtochiy Andriy B.
Published: October 2013

Multidomain periodically poled structure of 80 inversely poled domains of 50-micron-width each was fabricated in a 350-micron-thick 42-degrees-Y-rotated cut of LiTaO3 wafer. A multidomain structure in a ferroelectric plate is characterized by its own domain resonance where acoustic wavelength is equal to the domain period, and ultrasound speed is ∼6 km/s for LiTaO3 [I. V. Ostrovskii and A. B. Nadtochiy, Appl. Phys. Lett. 86, 222902 (2005)]. The rf impedance of the transducer as a function of frequency demonstrates a sharp resonance-antiresonance behavior at 57.6–60 MHz band (sample LTYR42B5a). The resonance observed is a pure multidomain resonance because crystal length is much longer than domain width. Overall dimensions of this transducer are 4×4×0.35 mm3, and irradiating surface area is 4×0.35 mm2. Two such transducers were used to model a delay line with water as a medium of propagation. A 1-μs burst with 59 MHz central frequency was delayed for 4.3 μs in the water. In conclusion, we present a new high frequency transducer for various applications in non-destructive testing, medicine, and biology [Patent Pending]. Experimental measurements and theoretical calculations are in good agreement.
Methodology of planar unsteady flow measurements in an excised larynx
Authors: Murugappan Shanmugam , Khosla Sid , Gutmark Ephraim , LakhamRaju Raghava
Published: October 2013

A methodology to obtain phase locked planar unsteady flow of the near field of supraglottal flow in an excised larynx using particle image velocimetry (PIV) is presented. Different steps involved in obtaining 2D flow field at different instances of the EGG or microphone signal and the structural motion of the vocal fold are discussed. Real time signal processing of the sensor signal coupled with the synchronization of the PIV flow field and high speed imaging of the vocal fold is used to evaluate the relationship between acoustics-structure and flow. Issues that can affect the accuracy of the flow field measurements and the reconstruction of the flow patterns at different instances during the EGG/microphone cycle were identified and suitable measures taken to resolve them are discussed. Some of these include simulating a symmetric vocal fold motion, maintaining a constant phonation frequency over the entire experimental run, preventing any spurious vectors that could arise due to reflection from the moist tissue surface or poor spatial or temporal resolution. Examples are also shown where the effect of these factors impact both the raw seeded image and correlation PIV algorithm used to extract the flow field vectors.
Flow induced aeroacoustic oscillations in a tube with a region of abrupt cross-sectional area increase
Authors: Bliss Donald , Sakimura Noah
Published: October 2013

The phenomenon of aeroacoustic oscillations induced by flow through a circular tube with an annular cavity region formed by an abrupt area increase is studied. At the beginning of the area increase, the flow separates and produces a shear layer that subsequently impinges on the downstream end of this region. The shear layer is a medium for propagation of convective vorticity waves. In the surrounding cavity, axial acoustic wave propagation can occur. The central flow region is governed by the convective wave equation, and the simple wave equation applies in the cavity. Coupled axial modes are identifiable as being primarily convective or primarily acoustic. The oscillation mechanism involves the interaction of upstream acoustic modes and downstream convective modes, coupled together by boundary conditions, and driven by mass addition and removal at the rear of the annular cavity caused by shear layer impingement on downstream edge. The oscillation process is analyzed using a cross-sectional averaging method for quasi one-dimensional waves to determine system wavenumbers and eigenmodes. Oscillation frequencies are determined by the condition of maximum energy extraction from the mean flow, arising from unstable convective waves, and by a compatible shear layer phase condition. A comparison with simple experiments is presented.
Vibroacoustics of musical wind instrument: Analysis of some pathological and nonpathological behaviors
Authors: Gautier Francois , Nief Guillaume , Gilbert Joel , Dalmont Jean-Pierre
Published: October 2013

Wall vibration of a musical wind instrument can be clearly noticed and measured in playing configuration. However, the problem of quantifying its effect on the emitted sound remains a subject of debate. Wall vibrations are generated by two mechanisms: (1) a mechanical source corresponding to the impacts of a reed (or musicians lips) on the mouthpiece and (2) an acoustical source due to the internal sound field. In this paper, we present an investigation of mechanism (2) using an experimental approach and a theoretical model of a generic simplified instrument (cylindrical vibrating shell, with a slightly distorted circular cross section). Analysis leads to the conclusion that, overall, vibroacoustic couplings are very small and do not induce any audible contribution. However, the wall vibration can play a significant role for some particular choices of material and geometry, which lead to coincidences between structural and acoustical modes. In these configurations, model and experiments show that the input acoustic impedance is clearly perturbed by wall vibrations. Using a blowing machine, it is shown that these perturbations can induce some timbre changes or some unstable oscillations regimes. Analysis of such pathological behaviors will be presented.
To play it is to improve it: An analysis of the ‘‘playing-in’’ phenomenon of stringed instruments
Authors: Piacsek Andrew A.
Published: October 2013

There is a growing interest in resolving the question of whether, and how, the act of playing a stringed instrument (in the violin and guitar families) improves its sound and playability over time. Although generally accepted by musicians, the causal connection is difficult to test due to the very large number of potentially relevant parameters, both physical and psychological. This presentation describes various historical references, interviews with musicians, and recent research on the subject of the ‘‘playing-in’’ phenomenon. Results will be presented from new experiments on the response of spruce panels subject to mechanical stimulus.
Determination of optimal near-field error sensor locations for active control of cooling fan noise using spherical harmonic expansions
Authors: Shafer Benjamin M. , Gee Kent L. , Sommerfeldt Scott D. , Fjeldsted J. Isaac
Published: October 2013

Recent developments in the active control of cooling fan noise have used near-field error sensors to drive the pressure to zero [K. L. Gee and S. D. Sommerfeldt, J. Acoust. Soc. Am. 115, 228–236 (2004)]. Theoretical mapping of near-field pressure during minimization of sound power reveals the location of pressure nulls that can be used to optimize the location of the error sensors. To this point, the locations of error sensors have been determined by modeling both the fan and the control loudspeakers as point monopoles. However, noise from an axial fan has monopole as well as multipole characteristics. The multipole characteristics of the fan can be obtained using a procedure based on the work of Martin and Roure [T. Martin and A. Roure, J. Sound Vib. 201, 577–593 (1997)]. Pressure values are obtained over a hemisphere in the far field of a primary source and the contributions from multipoles up to the second order, centered at the primary source, may be calculated using spherical harmonic expansions. The source information is then used in the aforementioned theoretical near-field calculation of pressure. Error sensors are positioned using this calculation and the global attenuation is compared to that of previous experiments.
Near field placement of error sensors in an active noise control application of axial cooling fans using flow visualization techniques
Authors: Duke Connor R. , Thomson Scott L. , Sommerfeldt Scott D. , Gee Kent L. , Duke Cole L. , Krueger David W.
Published: October 2013

The use of error sensors in the near field of an axial fan can be used to achieve global attenuation of the blade passage frequency and its harmonics. The pressure field produced by the minimized sound power radiation of the fan and control source configuration dictates possible locations of the error sensors by creating pressure nulls in the near field. By minimizing pressure at these locations, the minimized sound power field can be reproduced. Near field locations can be further investigated using qualitative flow visualization techniques including smoke visualization and quantitative particle image velocimetry (PIV). Analysis of the flow field will help to understand the presence of turbulent flow at the error sensors which can be a cause of a decreased signal to noise ratio. Optimal locations as well as mounting techniques for the error sensors will be discussed based on the flow field analysis. The effects of active noise control on the flow field produced by the fan will also be discussed.
Further developments in the active control of free-field sound using near-field energy-based error signals
Authors: Chester Ryan T. , Leishman Timothy W.
Published: October 2013

Practical efforts to actively control sound often require error sensors located in the acoustic or geometric near field of sound sources. Unfortunately, when using conventional acoustic pressure sensors, control performance often becomes very sensitive to sensor location. Optimal sensor positions are difficult to ascertain or maintain with changing system conditions. Alternate types of error sensors often lead to fewer position-dependent complications, producing global sound field control with greater ease and consistency. The distinct spatial and spectral uniformities of potential, kinetic, and total energy density for near-field error signal measurements will be discussed for the sound control of sources located in a free field. Numerical results will be compared to experimentally measured results.
Sonoluminescence from transient cavitation at high pressures in water and acetone
Authors: Gaitan D. Felipe , Tessien Ross A.
Published: October 2013

In highly degassed, clean liquids, transient acoustic cavitation can be triggered by fast neutrons, a phenomenon that has been known since ∼1960’s. The kinetic energy acquired by the nuclei allows it to ionize a small volume (∼100 nm dia.) in the liquid, creating a vapor cavity that would normally last a couple of microseconds. If the acoustic amplitude and phase are right, this cavity expands by several orders of magnitude (∼500 to 1500 microns dia.) and then collapses, emitting a short flash of light (1 to 40 nsec). The bubble continues to expand and collapse for several hundred cycles, eventually evolving into a larger (2 to 6 mm dia.) bubble cloud which lasts several milliseconds, depending on the conditions. The time duration of the light pulses is longer and their amplitude larger than those of single bubble sonoluminescense in water (∼100 to 300 psec, 105 photons/flash). The amplitude and time evolution of the light flashes has been analyzed as a function of the driving conditions and compared with computer simulations in an effort to infer the maximum plasma temperatures and densities, and perhaps the presence of shock waves, in the cavities.
Excitation of shape oscillation of bubble(s) in water under ultrasonic vibration
Authors: Ueno Ichiro , Kojo Tatsunori , Katase Shuhei
Published: October 2013

Behavior of a single or multiple bubbles of O(1 mm) in diameter under ultrasonic vibration was investigated experimentally. Excitations of surface wave and shape oscillation with distinct mode number were especially focused. Interaction between/among oscillating bubbles in a row rising in water was also introduced by considering bubbles volume variation during the oscillation. Through a series of the present experiment, variation of distinct mode number for shape oscillation as a function of the bubble radius is indicated.
Non-contact and local characterization of thin plates and cylindrical shells using the zero-group velocities (ZGV) Lamb modes
Authors: Clorennec Dominique , Prada Claire , Royer Daniel , Murray Todd
Published: October 2013

The group velocity of the symmetrical S1 Lamb mode vanishes if the Poisson’s ratio v is smaller than 0.45. At this ZGV point, the frequency×thickness product undergoes a minimum and two modes (S1 and S2b) propagate with opposite phase velocities. In our experiments, this ZGV mode is generated by a 10-ns laser pulse and detected at the same point using an optical interferometer. The spectrum of the signal reveals an intense narrow peak corresponding to the S1-ZGV Lamb mode resonance. A similar phenomena occurs for the A2 Lamb mode if v<0.31. The minima of the frequency×thickness product of the S1 and A2 modes only depend on v. The ratio of the resonance frequencies of these two modes is independent of the thickness. Thus, this experimental configuration allows a local and absolute measurement of v. Knowing h, the measurement of these resonance frequencies provides the bulk waves velocities with a high accuracy. This non-contact method was tested on different plates and shells. The same behaviour is observed in a cubic silicon crystal. Moreover in such anisotropic plates, we show that the resonance frequencies can be selected using a line laser source. These frequencies are well predicted by the theoretical dispersion curves.
Naturalistic auditory scene analysis in children and adults
Authors: Leech Robert , Dick Fred , Aydelott Jennifer , Gygi Brian
Published: October 2013

In order to make sense of natural auditory environments, the developing child must learn to ‘‘navigate’’ through complex auditory scenes in order to segment out relevant auditory information from irrelevant sounds. This study investigated some of the informational and attentional factors that constrain environmental sound detection in auditory scenes, and how these factors change over development. Thirty-two children (aged 9–12 years) and 16 adults were asked to detect short target environmental sounds (e.g., a dog barking) within longer environmental background sounds (e.g., a barn) presented dichotically. The target environmental sounds were either congruent (i.e., normally associated with the background) or incongruent. Subjects heard either a single background presented to both the ipsilateral and contralateral ears or else different background sounds presented to the different ears. Results indicate that children’s, but not adults’ target detection is substantially less accurate when listening to two auditory scenes than to a single scene presented in both ears, suggesting a developmental shift in listeners’ abilities to process multiple information streams. Interestingly, both children and adults find incongruent sounds more salient than congruent sounds. Furthermore, this incongruence ‘‘pop-out’’ effect is greatly reduced in the presence of the dual background (informational masking) condition.
Cochlear implant-mediated perception of non-linguistic sounds
Authors: Inverso Yell , Bickley Corinne , Limb Charles
Published: October 2013

Cochlear implants (CI) have provided sound perception to profoundly deaf individuals, revolutionizing the treatment of sensorineural hearing loss. Thus far, the overwhelming majority of test measures to assess implant candidacy, efficacy, and progress are based on speech perception. Non-linguistic speech (NLS) stimuli, by comparison, have received comparatively little attention, despite the importance of NLS sounds for environmental sound awareness. For the prelingually deafened population, in whom speech perception may never be fully realized, NLS perception is an especially critical area deserving further study. The specific aims of this study were to determine the accuracy with which postlingually deafened CI users perceive NLS, and to determine if there is an association between acoustic characteristics of the NLS and ability to identify these sounds using a CI. We used five main categories of NLS: human vocal non-linguistic, animal/insect, nature/ambient, mechanical/alerting, and musical to comprise a test battery that was given to 10 postlingually deafened CI users. Results of the pilot study showed overall poor ability of CI users to recognize NLS. Furthermore, an association between speech perception and accuracy of NLS was identified. Our results suggest that NLS is a difficult category of complex sound for CI users to perceive.
Amplification and training effects in resolution and cross-spectral integration of redundant cues
Authors: Espinoza-Varas Blas , Bingabr Mohamed , Loizou Philip
Published: October 2013

Speech recognition of hearing-aid and cochlear-implant users is constrained partly by inefficient integration of information conveyed by multiple frequency channels: owing to cross-channel interference, multi-channel recognition accuracy is often lower than the sum of single-channel accuracies, especially if one channel has impaired sensitivity. With complex tones consisting of a mid- (M) and a high-frequency (H) component (1000 and 3127 Hz), the resolution and cross-spectral integration (CSI) of simultaneous increments in M frequency (IFM) and H duration (ITH) were studied as a function of H amplification and training; M and H impinged, respectively, on normal- and impaired-sensitivity regions of listeners with sensorineural losses. Without amplification, ITH resolution was negligible, the IFM discrimination threshold did not decrease with ITH, and CSI was nil. With H amplification, resolution improved moderately for ITH but decreased for IFM; that is, increasing H audibility interfered with IFM resolution. As a result, the IFM discrimination threshold decreased with ITH but CSI was inefficient and remained so after extensive training. However, ITH resolution and CSI efficiency improved significantly by training listeners to attend to H and respond only on the bases of ITH. The improvement associated with H amplification increased significantly with high-frequency listening training. [Work supported by PHF.]
An active noise cancellation system to reduce the intense noise caused by magnetic resonance imaging
Authors: Hall Deborah , Chambers John , Quinn Kimberly , Akeroyd Michael
Published: October 2013

Magnetic resonance imaging (MRI) has become the dominant technique for noninvasive measurements of central auditory function in humans, but its operation generates intense acoustic noise (some 115 decibels). Although this can typically be attenuated by about 30 decibels with ear defenders, there is considerable scope for additional benefit. We took advantage of two features of the sound: (i) its predictable temporal onset, and (ii) its fixed power spectrum (which is dominated by intense harmonic components at low frequencies) to engineer an active noise cancellation (ANC) system to achieve further noise reduction. We measured its perceptual effectiveness by collecting detection thresholds for a tonal signal, masked by the image acquisition noise of the scanner (Philips 3 Tesla Intera) with and without the ANC operating. We presented signal frequencies centered at the peaks of the objective cancellation (150, 300, and 600 Hz), plus 450 Hz (a control frequency achieving no significant acoustic cancellation). Across four listeners, the ANC system gave average benefits of 4, 11, 15 dB, respectively, at the peaks and 10 dB at 450 Hz. These results confirm that the system offers substantial benefits for audibility in MR research. Moreover, the ANC equipment does not interfere with image quality.
Spatial-temporal patterns of vowel articulation: A cross-speaker study
Authors: Tasko Stephen
Published: October 2013

An important goal in speech production research is to establish a quantitative description of normal or typical articulatory behavior. This description should be expressed in a compact but meaningful way and be robust enough to generalize across a large number of speakers who differ in physical size, gender, age, etc. This is a significant challenge given the numerous degrees of freedom within the articulatory system and the range of speaker variability. However, Hashi et al. [J. Acoust. Soc. Am. 104, 2426–2437 (1998)] used x-ray microbeam data to develop a procedure for normalizing vocal tract size and shape. This procedure reduced cross-speaker variation in the articulatory postures of vowels. The authors limited their analysis to a single time slice at the acoustic steady state. There is little available information regarding speaker-general time-varying articulatory patterns associated with vowel production. This study will address this issue. Fifty-three healthy speakers from the University of Wisconsin x-ray microbeam database served as subjects. The speech task consisted of productions of American English vowels in a /sVd/ context. Analysis focused on the movement of a number of vocal tract markers over the duration of each vowel. Vowel-specific spatial temporal patterns common to the speaker group will be described.
The development of relative amplitude changes across acoustic discontinuities in nasal+vowel syllables
Authors: Oakey Meredith A. , Ohde Ralph N.
Published: October 2013

In adult productions of nasal+vowel syllables, relative amplitude changes occur in various frequency regions across acoustic discontinuities and provide important cues as to the place of articulation of nasal consonants. The purpose of this study was to investigate the development of relative amplitude changes in children as potential acoustic correlates to place of articulation. Four age groups of eight participants each (3, 5, 7, adult) served as speakers. Participants produced five productions each of CV syllables comprised of [m] and [n] in the context of four vowels ([i æ u ■]). These syllables were segmented into approximately 25 ms segments of the murmur and 25 ms segments of the vowel bordering the period of discontinuity. The relative amplitude changes in low- and high-frequency ranges from the murmur to the vowel were determined using summed amplitude information from fast Fourier transform (FFT) analyses. Previous research showed systematic differences in relative amplitude between [m] and [n] in adult syllable productions, but only marginal differences were observed in very young children’s speech. The relative amplitude property, a landmark cue representing place of articulation of nasal consonants, is predicted to develop with age based on these preliminary analyses. [Work supported by NIH and an ASHA SPARC Award.]
Modeling vowel normalization and sound perception as sequential processes
Authors: Hoffmann Bion Ricardo A. , Escudero Paola
Published: October 2013

This study constitutes the first attempt at combining vowel normalization procedures with the linguistic perception framework of stochastic Optimality Theory and the Gradual Learning Algorithm (Boersma, 1998). Towards this end, virtual learners possessing different normalization procedures, and a control learner with no normalization procedure, were trained to perceive Brazilian Portuguese and American English vowels. The only parameters fed into the model were the first two formants of the vowels. The simulations assume that: (i) vowel normalization occurs prior to vowel categorization, (ii) each learner has acquired a different normalization algorithm at the time of the simulations, and (iii) perceptual learning takes place when mismatches between the word intended by the speaker and the word perceived by the virtual listener occur (Escudero & Boersma 2004). Our results show that learners equipped with normalization algorithms outperformed the control learner, obtaining accuracy scores from 20 to 30% higher. When equipped with vowel-extrinsic procedures, learners managed to reach more than 90% of correct responses. Thus, a formal model in which normalization and sound perception are implemented as two sequential processes delivers the expected results, as it accurately models vowel perception even when the training and testing sets have speakers with different ages and gender.
Effects of dialect variation on speeded word classification
Authors: Clopper Cynthia G.
Published: October 2013

Dialect variation has been found to significantly affect speech intelligibility in noise. The current experiment was designed to examine the effects of dialect variation on the processing of a single phonemic contrast. Participants were presented with tokens of the words ‘‘bad’’ and ‘‘bed’’ produced by talkers from Chicago and Indianapolis. The vowels in the Chicago tokens were shifted according to the Northern Cities shift (raised and fronted ‘‘bad,’’ lowered and backed ‘‘bed’’). The Indianapolis tokens were unshifted. The participants were asked to classify each token as ‘‘bad’’ or ‘‘bed’’ as quickly as possible in three conditions: Chicago tokens only, Indianapolis tokens only, or mixed Chicago and Indianapolis tokens. While overall accuracy was high in all three conditions, participants were slower in the Chicago-only and mixed conditions than in the Indianapolis-only condition. In addition, participants responded more slowly to the Indianapolis tokens in the mixed condition than in the Indianapolis-only condition, but response times to the Chicago tokens did not differ across the two conditions. These results suggest that acoustic-phonetic dialect differences interfere with lexical processing and that global effects of dialect variation on speech intelligibility may reflect confusions between specific pairs of phonemes as a result of subphonemic vowel shifts.
Classification of active sonar detections with class specific method
Authors: Gaumond Charles F. , Baer Ralph N.
Published: October 2013

The use of the Class Specific Method (CSM) [P. M. Baggenstoss, Trans. Sig. Proc. 47, 3428–3432 (1999)] is demonstrated with numerically simulated data. The two models of a cylindrical shell and a fish school are shown to generate sufficient statistics with appropriate assumptions. The common reference signal for the CSM is Gaussian white noise. An interpretation of the resulting conditional probability density functions is given, which leads to a numerical regularization. The resulting implementation of the CSM is demonstrated using numerically modeled data of variable bandwidth with variable amounts of additive Gaussian white noise. This approach enables the evaluation of bandwidth requirements for sufficient classification performance. The method is shown to be generalizable to include effects of propagation. [Work supported by the Office of Naval Research.]
Acoustical requirements for music in non-Western worship spaces
Authors: Calamia Paul , Braasch Jonas
Published: October 2013

In this talk, an overview of different non-Western musical traditions for worship, and the particular architectural-acoustic requirements of these traditions, will be given. While the pipe organ, which plays a central role in the Christian and Jewish worship traditions, is rarely found in other religious services, the other two typical western worship instruments, choir and bells, serve in many other worship traditions as well. Brass instruments also are found in both Western and non-Western worship traditions, for example in the typical church brass ensembles with trumpets, trombones, horns, and tubas, and the long Tibetan temple trumpets. Percussion instruments, such as those in the Indonesian Gamelan Ensemble, are often an important element in non-Western rituals. However, aside from bells, they do not have a strong tradition in Western worship services, which is not surprising given the long reverberation times in most churches. The talk will focus on those worship traditions that are not addressed by other speakers in this session.
Acoustical design strategies for contemporary music in worship
Authors: Henderson Paul D.
Published: October 2013

Historically, acoustical design for traditional worship music has sought to naturally reinforce instruments and vocalists by carefully exploiting room reflections. However, the advent of ‘‘contemporary’’ worship and the widespread use of reinforced music have paralleled a clear change in the architecture, seating capacity, and expected acoustical signature of the worship sanctuary. In addition, many modern worship services employ a hybrid of musical styles within a single service, such as choral performances, orchestras, electronic music, and dramatic presentations. While some may consider a highly absorptive room to be an ideal listening environment, this approach neglects several key aspects of the contemporary worship experience, such as ensemble support for choirs as well as for the audience during congregational singing. Here, acoustical criteria are reviewed for the design of architectural elements within a contemporary worship space. Design strategies are presented for integrating effective acoustical elements within the framework of necessary technical systems. Case studies are presented of recent sanctuary designs of varying size to demonstrate the relationship between architectural techniques and the musical experience.
The internal representation of high-frequency spectral notches
Authors: Alves-Pinto Ana , Lopez-Poveda Enrique A.
Published: October 2013

To discriminate between broadband noises with and without a high-frequency spectral notch is more difficult at 70–80 dB SPL than at lower or higher levels [A. Alves-Pinto and E. Lopez-Poveda, J. Acoust. Soc. Am. 118, 2548 (2005)]. One possible explanation is that the notch is less clearly represented internally at 70–80 dB SPL than at any other level. To test this hypothesis, forward-masking patterns were measured for flat-spectrum- and notch-noise maskers for masker levels of 50, 70, 80, and 90 dB SPL. To separate out the effects of peripheral compression and of the broadening of auditory filters with increasing level on the notch internal representation, the masking patterns were measured in two conditions: (1) varying the masker-probe intervals to achieve similar masked thresholds for different masker levels and (2) fixing the time interval at 2 ms. The depth of the spectral notch in the masking pattern decreased gradually with increasing level, mostly as a result of compression. This result is inconsistent with improvement in spectral discrimination above 80 dB SPL and hence undermines the common view that high-frequency spectral notches must be encoded in the rate-profile of auditory nerve fibers (see also the companion paper by Lopez-Poveda et al.).
How often is maximum speed of articulation approached in speech?
Authors: Xu Yi
Published: October 2013

According to the principle of economy of effort, dynamic extremes such as maximum speed of articulatory movement would be avoided as much as possible. Recent findings about F0 dynamics suggest, however, that maximum speed of pitch change is actually often approached in the production of tone and intonation. Here we investigate the possibility that segmental production also often involves motor movements that approach the maximum speed of articulation. Native speakers of American English were asked to produce repetitive syllable sequences such as yayayayaya and wiwiwiwiwi as fast as possible by imitating the same sequences that had been artificially accelerated through resynthesis. They were also asked to produce meaningful sentences containing the same syllables at normal and fast speaking rates. The speed of articulation in the syllable sequences and in the sentences are compared in terms of peak velocity of formant movement as a function of movement amplitude. If peak velocity is comparable across the conditions, it is an indication that speech production is operated near the performance ceiling, which would imply that much of the contextual variability in speech, especially that related to undershoot, has more to do with dynamic constraints of articulation than with economy of effort.