bluuebunny/crossref_metadata_2025 huggingface dataset:
Damping measurements of highly damped wavy composite structures
Authors: Sommerfeldt Scott D. , Pratt William F. , Allen Matthew S.
Published: October 2013

Wavy composite material is a composite that has been developed in recent years that uses opposing sinusoidal fiber waveforms in adjacent layers in a manner that enhances the constrained layer damping effect in the material. Analysis of the material has predicted both high damping and stiffness, which is contrary to many materials where increased damping generally leads to decreased stiffness of the material. To validate the analysis, a test system has been developed to measure both the damping and the stiffness properties of the material under axial excitation. The system has been shown to be capable of measuring frequency dependent damping coefficients of less than 1%. Tests on the wavy composite have led to a characterization of the material over a broad range of frequency and temperature that agrees well with predicted values, and allows one to design the wavy composite lay-up to give a desired performance at a given temperature and frequency. Damping measurements as high as 30% have been measured, while maintaining stiffness properties that are comparable to materials such as aluminum and titanium, using standard graphite fibers.
Acoustic characteristics of fricatives in Arabic
Authors: Al-Khairy Mohamed , Wayland Ratree
Published: October 2013

Previous work on English fricatives suggests that a conglomerate of acoustic cues exist to differentiate among fricatives produced at different places of articulation [e.g., Jongman (2000)]. These include spectral peak location, spectral moments, F2 onset frequency, noise amplitude, noise duration, etc. The goal of this study is to investigate whether or not acoustic characteristics served to classify English fricatives place of articulation can be used to classify fricatives place of articulation in Makkan Arabic. Unlike English, this dialect of Arabic includes velar, pharyngeal, and glottal fricatives in its phonological inventory. Thus of great interest is whether or not cues to fricatives place of articulation thus far discovered will be able to successfully differentiate among these rare fricatives. All acoustic measurements found in Jongman’s 2000 work including locus equations will be used to explore this important question, and results of this study will be compared and contrasted with those of earlier studies.
Tonal assimilation in Thai
Authors: Roengpitya Rungpat , Ohala John
Published: October 2013

Thai has five distinctive tones: mid, low, rising-falling, high, and falling-rising. In this paper, the behavior of Thai tones when they were concatenated with other tones was studied. The target utterances were Thai meaningful and nonsense words with the shape C1VC2, where the C1 was a nasal, the V was /i/ or /i:/, bearing each of the five tones, and C2 was either a nasal or a voiceless stop. The targeted words were spoken by three native speakers of Thai in isolation and in five different tonal contexts, digitally recorded, and measured for the fundamental frequency of the targeted words and the following words. The results showed that the tones of the targeted words normally started at the vowel onset but their offset carried over to the beginnings of the tones of the following words. This carryover effect [previously noted by Xu (1997) for Mandarin tones] occurred more for the targeted words with the final nasals than for the ones with the final stops.
Variation of reaction times for the recognition of voiced plosives with preceding noise duration
Authors: Ainsworth William
Published: October 2013

Voiced plosives in noise which precedes the speech are recognized correctly more often than in noise which begins at the start of the speech. This effect may be due to noise adaptation of firing thresholds of neurones in the cochlear nerve effectively performing spectral subtraction, or it may be due to perceptual streaming at a higher level of the auditory system. In order to investigate this further, reaction times for recognition have been measured. It was found that the reaction time initially reduces for a preceding noise of 100–200 ms, then increases as the noise duration is lengthened (at least up to 800 ms). Furthermore it was found that the reaction time is reduced when the recognition score is higher. Assuming that recognition consists of processing which increases with the noise duration but decreases for good internal matches, a model of reaction time as a function of preceding noise duration has been developed. It consists of two negative exponential functions: one a function of noise duration and the other a function of recognition score. Good agreement between experimental data and the model has been found. [Work supported by EU TMR Contact No. FMRX-CT97-0150.]
Gestural timing effects in the ‘‘perfect memory’’ sequence observed under three rates by electromagnetometry
Authors: Tiede Mark K. , Perkell Joseph , Zandipour Majid , Matthies Melanie
Published: October 2013

In a well-known example due to Browman and Goldstein [Lab. Phon. I, 341–376 (1990)] the /ktm/ sequence in the phrase ‘‘perfect memory’’ is contrasted between careful (list) and fluent production conditions. X-ray microbeam data were used to show that although in the fluent case coproduction of the /m/ can mask the acoustic releases of the /k/ and /t/, both stops are nonetheless articulated. The current work uses EMMA data to examine this sequence in greater detail: 8 subjects produced the phrase in a carrier context under normal, fast, and clear rate conditions. Results confirm that tongue dorsum and tip movements toward velar and apical closure occur regardless of rate and observable acoustic effect. In addition, while movement amplitudes decreased somewhat as rate increased, little variation in the durations associated with the consonant gestures was observed. Instead, changes in rate primarily effected V to V duration and the relative phasing of the velar and apical closing gestures: the tongue tip maximum (/t/) lagged that of the tongue dorsum (/k/) in clear speech, was aligned with it in normal speech, and generally anticipated it in the fast rate condition. [Work supported by NIH.]
Recognizing vowels from narrow band spectra
Authors: Hillenbrand James M. , Houde Robert A.
Published: October 2013

Most models of vowel recognition begin with a representation consisting of either a smooth envelope spectrum or formant frequencies extracted from those envelope spectra. In the present report we describe a classification method that performs pattern matching by comparing high-resolution vowel spectra (i.e., spectra that retain harmonics of the voice source) with a set of smoothed spectral-shape templates for each of the vowels derived by averaging harmonic spectra from a large database of /hVd/ utterances spoken by men, women, and children [Hillenbrand et al., J. Acoust. Soc. Am. 97, 3099–3111 (1995)]. [Work supported by NIH.]
Dual band speech intelligibility: Implications of some novel observations concerning amplitude mismatch and asynchrony
Authors: Warren Richard M. , Bashford James A. , Lenz Peter W.
Published: October 2013

Two 1/3-octave bands of everyday sentences (center frequencies 1 and 3 kHz) were employed. To avoid the major contribution of slopes (even when 100 dB/octave) upon intelligibility [Warren and Bashford, J. Acoust. Soc. Am. 106, L47 (1999); Warren et al., J. Acoust. Soc. Am. 108, 1264 (2000)], nearly vertical slopes were employed (4000 order FIR filtering producing 2000 dB/octave slopes). Heard alone at 75 dB, intelligibilities were 5% (1 kHz) and 10% (3 kHz); together, the synergistic score was 80%. When the 3-kHz band was kept at 75 dB and the 1-kHz band’s amplitude was decreased systematically, intelligibility remained unchanged (1.4%) from 75 to 45 dB (amplitude ratio of 1000:1). But when both bands were at their normal relative levels, and one band was delayed relative to the other, intelligibility dropped to half with asynchrony of only about 35 ms (approximately half the duration of the average phoneme), decreasing to an intelligibility score of a single band when asynchrony approximated phonemic duration. It is suggested that broadband speech processing relies upon cross-frequency comparison of dynamic changes in local patterns with little regard to differences in pattern amplitude. This comparison appears to be based upon units approximating the duration of the average phoneme. [Work supported by NIH.]
Seabed characterization from statistical analysis of high-frequency data
Authors: Dugelay Samantha J. , Brothers Richard J. , Heald Gary J.
Published: October 2013

Results are presented from statistical analysis of experimental and simulated high-frequency seabed backscatter data. The statistical laws employed in the analysis were the Rayleigh distribution, the Rayleigh mixture, and the K-law. The significance of the distribution parameters and their estimation from the data are explained. The link between the parameters and seabed type has been theoretically examined through a detailed study of the variation of statistical laws with grazing angle. Experimental data were collected using a 150-kHz wide-band sonar at three different sites, providing different sediment types. The validity of the above statistical laws was investigated and found to be dependent on sonar geometry. The estimated parameters of the three distributions have been examined for their potential in seabed characterization. Simulations have been compared with experimental data for validation purposes. These results have then been used to investigate the theory developed beyond the scope of the recorded data.
Non-native speech production (II): phonemic errors by position-in-word and intelligibility
Authors: Bent Tessa , Smith Bruce L. , Lodewyck Danielle , Bradlow Ann R.
Published: October 2013

This study considered the distribution of non-native talker phonemic errors by position-in-word, and their differential effects on non-native speech intelligibility. Based on the structure of words in the native language of the talkers (i.e., Chinese), it was hypothesized that word-initial phonemes would be produced more accurately than word-final phonemes. Additionally, based on models of lexical access (e.g., cohort model), it was hypothesized that phonemic errors in the word-initial position would be more detrimental to intelligibility than phonemic errors later in the word. 15 talkers of Chinese-accented English produced 16 simple declarative sentences. These recordings were phonetically transcribed to determine the number and type of production errors and presented to native English listeners for intelligibility testing. Results showed that, as predicted, word-initial phonemes were produced more accurately (92% correct) than word-final phonemes (82% correct) [t(14)=3.815, p<0.01]. Furthermore, word-initial singleton consonants and vowels correlated with intelligibility (Rho=0.738, p<0.01 and Rho=0.692, p<0.01, respectively). In contrast, initial and final consonant clusters, word-final singleton consonants, and within-word consonants were not significantly correlated with intelligibility. These results demonstrate that, for a variety of talker- and listener-related reasons, a phoneme’s position within the word exerts an important influence on both its production and perception. [Work supported by NIH-NIDCD Grant No. DC03176.]
Analysis of yes–no and confidence-rating word recognition response formats
Authors: Goshorn Edward L. , Goshorn Jennifer D.
Published: October 2013

The effects of two response formats (yes–no and confidence-rating) on percent correct, d′, and response criterion were examined. Diagnostic Rhyme Test words were presented in white noise (3 and 6 dB signal to noise ratios) to eight normal hearing subjects at 70 and 90 dB SPL; three replicates were obtained. For the yes–no format, subjects checked ‘‘yes’’ or ‘‘no’’ that a single response option matched the stimulus. For the confidence-rating format, subjects checked 1 of 2 response options and indicated confidence, or lack thereof, that the response matched the stimulus by marking ‘‘yes’’ or ‘‘no.’’ Both formats yield signal detection theory (SDT) estimates of d′ and response criterion, but differ in categorizing responses as hits, misses, false alarms, and correct rejections. A significant difference was found between response formats for percent correct and response criterion but not for d′. The effects of signal to noise ratio were significant but parallel across response format for percent correct, d′, and response criterion. Results indicate that response format may significantly affect conventional measures such as percent correct but not SDT measures that separate sensitivity and response criterion. The use of SDT measures in word recognition procedures is supported.
Aging, injury, disease, and noise in marine mammal ears
Authors: Ketten D. R. , O’Malley J. , Moore P. W. B. , Ridgway S. , Merigo C.
Published: October 2013

In humans, hearing is lost with age, trauma, and disease. It is likely marine mammals sustain similar damage, but currently we have little direct data on their incidence of hearing loss. Marine mammals represent an interesting hearing paradox. Because their ears are fundamentally the same as human ears, we expect they have similar loss mechanisms, but they evolved in a high noise environment and have adaptations that deter pressure-induced trauma. These adaptations may equate to ‘‘tougher’’ ears. This paper summarizes evidence from computerized tomography and histologic exams for grades and etiology of hearing loss in captive and wild marine mammals. The data indicate dolphins have hypertrophic inner ears elements (i.e., stria vascularis, spiral ligament, basement membrane) that imply greater robustness and faster recovery times than pinniped ears. However, older dolphins and seals alike develop degenerative pathologies, including neural, hair cell, support cell, and bony loss that parallel presbycusic changes in older humans and are consistent with substantial hearing loss. The results suggest whales and dolphins may be less subject to temporary threshold shifts than pinnipeds, but both are equally liable to hearing loss from severe trauma or age. [Work supported by ONR and NOAA Fisheries.]
Development and commercialization of high-performance sensorics utilizing single piezoelectric crystals
Authors: Wlodkowski Paul A.
Published: October 2013

Wilcoxon Research, Inc., has two focused research efforts on developing high-performance sensorics with single piezoelectric crystals. The first program belongs to the emerging class of directional acoustic transducers, also known as vector sensors. The second program involves the development of mesoscale accelerometers. Recognizing both the exceptional electromechanical properties and the limitations of the new piezoelectric material, the company has identified the aforementioned areas as those most promising for commercialization. Extensive materials characterization, prototype fabrication and testing have supported this direction. Wilcoxon Research has successfully demonstrated the unprecedented performance of both classes of transducers. This has been realized through a synergy of the electromechanical properties of single piezoelectric crystals, a novel method of strain amplification in the material, and low-noise signal conditioning customized for the PMNT and PZNT crystals. Typically, the signal-to-noise ratio of the single piezoelectric-based sensors is 15 dB higher via-à-vis conventional transducers utilizing polycrystalline, PZT ceramic materials as the sensing element.
The influence of a quiet facade on road traffic annoyance
Authors: Gjestland Truls , Stofringsdal Bard
Published: October 2013

A situation (1) with equal traffic noise on all four sides of a residence, has been compared with a situation (2) with a high level on one side and low on the other sides. A laboratory experiment has been conducted to have the test persons adjust the high or the low noise level in situation (2), so that the situation is assessed ‘‘equally annoying’’ as situation (1). The results indicate that the annoyance caused by road traffic noise can be reduced if at least one quiet side of the house can be achieved.
Preliminary studies on respiratory activity in speech
Authors: Ladefoged Peter , Loeb Gerald
Published: October 2013

Work at Edinburgh University in the 1950s, summarized by Ladefoged [Three Area of Experimental Phonetics (Oxford University Press, Oxford, 1967)] claimed that (1) the mean power for speech was provided by actions of the respiratory muscles. The external intercostals check the outgoing airflow when speaking with high lung volumes, and the internal intercostals, rectus abdominis, and other muscles become more active as lung volume decreases. (2) Stressed syllables are produced by increases of respiratory power above the mean, usually by further activity of the internal intercostals. Hixon and Weismer (1995) pointed out technical limitations of these early studies, but wrongly indicated that they were of little value. These studies have been replicated with modern methods to measure intramuscular EMG and airflow and pressure. The two subjects studied to date follow the pattern previously described. In addition the improved techniques indicate that speakers exercise further control by bringing in stabilizing antagonistic muscles. These results are consistent with the general hypothesis that the central nervous system is able to control subglottal pressure by using various combinations of passive elastic and active muscle forces, thereby achieving motor equivalence and acoustic invariance over a wide range of lung volumes.
Intrinsic F0 and tongue depth in ATR languages
Authors: Whalen D. H. , Gick Bryan
Published: October 2013

Intrinsic F0 (IF0) is the tendency for high vowels to have a higher F0 than low vowels. While IF0 has been found for every language studied [D. H. Whalen and A. Levitt, J. Phonetics 23, 349–366 (1995)], none of those languages distinctively contrasted advanced tongue root (ATR). Most languages conflate high tongue position with advanced tongue root, but some distinguish vowels by ATR. Here we report on two such languages, Igbo (a Niger-Congo language of Nigeria) and Kinande (a Bantu language of Congo). Acoustic analysis of F0 in Igbo suggests that +ATR vowels have higher F0s than their ATR counterparts. For Kinande, a combined acoustic and ultrasound study was performed. All five vowels /ieaou/ occur in ±ATR versions. All +ATR vowels except /i/ had higher F0s than their ATR counterparts. Horizontal depth at tongue root (distance from the jaw to the anterior pharyngeal wall) varied with ATR, as expected, and correlated with F0. Height also affected F0, in an amount of the same magnitude as for ATR. Some of IF0 appears to be attributable to pharyngeal shape (inferred from tongue depth), not to tongue height. Further work will examine which plays the more important role. [Work supported by NIH Grant DC-02717.]
Analysis of acoustic factors contributing to poor quality of electrolaryngeal speech
Authors: Meltzner Geoffrey S. , Hillman Robert E. , Stevens Kenneth N.
Published: October 2013

A large percentage of patients who have undergone laryngectomy to treat advanced laryngeal cancer rely on an electrolarynx (EL) to communicate orally. While serviceable, EL speech is plagued by shortcomings in both quality and intelligibility. As part of a larger ongoing effort to improve the oral communication of EL users, this study seeks to better quantify the sources and impacts of abnormal acoustic properties typically found in EL speech. Two EL characteristics, altered voicing source location and directly radiated self-noise, were investigated by recording EL speech tokens in two recording conditions: (1) in an acoustic chamber (self-noise present) and (2) through a specially constructed port into an acoustic chamber (self-noise absent). An analysis of several vowels reveals that one or more of the first three formants are often masked by the direct noise and that their amplitudes are affected by EL location on the neck. Results are discussed relative to a comprehensive comparative analysis of pre-laryngectomy versus post-laryngectomy EL speech, and with respect to a model of EL speech production. [Work supported by W. M. Keck Foundation and VA Grant C2243-2DC.]
High-frequency harmonics and source level of humpback whale songs
Authors: Au Whitlow , James Darling , Andrews Kimberly
Published: October 2013

The songs of 8 male humpback whales were recorded at ranges varying from 20 to 40 m with a calibrated system that had a flat frequency response to 22 kHz. The songs consisted of bursts of sounds called units. Units were organized into phrases and phrases into themes. Most of the units had mean duration between 1 and 2 s and mean silent periods between units between 1 and 2 s. Many of the recorded songs contained units that had high-frequency harmonics that extended beyond 15 kHz. The amplitudes of the higher-frequency harmonics of some units were within 18–24 dB of the fundamental or the highest level harmonic at frequencies out to 13.5 kHz. These harmonic results suggest that humpback whale songs have a broadband quality not previously reported and may provide some insights on the high-frequency limit of hearing in these whales. The source levels of the different songs were also estimated by considering the root mean square sound pressure level referenced to 1 m for the unit with the largest level for each different phrase within a song. Source levels varied between 171 and 189 dB re: 1 μPa.
Multiyear study of blue whale calls in the north Pacific
Authors: Hildebrand John A. , McDonald Mark A. , Andrew Rex , Mercer James A. , Howe Bruce M.
Published: October 2013

Multiyear acoustic recordings provide new insight on blue whale behavior in the Northern Pacific. We analyze six years of blue whale acoustic recordings made in the North Pacific as part of the ATOC (Acoustic Thermometry of Ocean Climate) and NPAL (North Pacific Acoustic Laboratory) projects. Blue whale calls are recorded as a component of ambient sound data, preserved as spectra with 500 Hz Nyquist frequency in 1 Hz bins, averaged over 170 s and recorded at 5 min intervals at each of 13 sites from 1994 to the present. These data verify a separation of blue whale calls into a Western Pacific version with two primary frequencies near 20 Hz and weak harmonic components, and an Eastern Pacific version with a primary near 17 Hz, a strong harmonic component near 50 Hz and a strong overtone near 90 Hz. The frequency of the Eastern Pacific blue whale call has shifted downward throughout the last 40 years, and the present data, combined with published sources, show the frequency shift to be secular and nearly linear with time. [Work supported by ONR.]
Do manatees talk during sex?
Authors: Self-Sullivan Caryn , Gilbertson Tamra , Evans William E.
Published: October 2013

On January 13, 1999, manatee vocalizations were recorded during a mating herd event in the Orange River, Florida. Although copulation could not be observed, multiple males were observed with exposed penises. During one 25 min sample (1300–1325 h), over 400 manatee signals were recorded. In March 2000, each signal was captured and digitized from the analog tape using a Marantz PMD 501, Ashly equalizer (gain=0, filter=0), MAC 8100, and Canary 1.2.1. In general, signals were 100–200 ms in length, highly harmonic (up to 8 harmonics ranging from 1 to 16 kHz), with little or no frequency modulation. Intervals between signals ranged from less than 1 s to 14 s (mean = 3 s), indicating that manatees do indeed talk (a lot) during sex. Noise from two passing boats was also recorded during the sample period. One abnormally low-frequency signal (0.4 kHz) was recorded during one boat pass. This apparent manatee vocalization could be seen and heard below the boat noise frequency band.
Multibeam echo-sounding measurement of the microbubble field in a ship’s wake
Authors: Gallaudet Timothy C. , de Moustier Christian P.
Published: October 2013

Acoustic data collected with the U.S. Navy’s 68 kHz Toroidal Volume Search Sonar (TVSS) system were used to measure the microbubble field generated by the wake of the towing vessel at a constant distance of 18 ship lengths astern. Swath bathymetry beamforming and echo detection techniques were adapted to map the sea surface and the spatial distribution of bubble fields observable in the ocean volume with the TVSS. The sonar was towed at 78 m depth yielding a sea surface measurement swath roughly 550 m wide thus allowing observations of wake bubble fields across three parallel ship tracks spaced 200 m apart and over 22 min after generation. Measurements in microbubble fields about 3 min after generation by the ship’s wake yielded an average vertical attenuation of 2.1 dB/m and a maximum acoustic volume scattering strength of −17.1 dB. [Work supported by the U.S. Naval Research Laboratory.]
Underwater loudness for tones
Authors: Cudahy Edward A. , Schwaller Derek
Published: October 2013

The loudness for pure tones was measured by loudness matching for 1-s pure tones from 100 to 50000 Hz. The standard tone was 1000 Hz. Subjects were instructed to match the loudness of the comparison tone at one of the test frequencies to the loudness of the standard tone. The standard was presented at one of five sound pressure levels (SPL) for each set of frequencies. The SPL was varied randomly across a test series. The subjects were bareheaded U.S. Navy divers tested at a depth of 3 m. All subjects had normal hearing. The tones were presented to the right side of the subject from an array of underwater sound projectors. The SPL was calibrated at the location of the subject’s head with the subject absent. The loudness increased more rapidly as a function of standard SPL at mid-frequencies than at either high or low frequencies. The most compact loudness contours (the least SPL change across the range of standard SPL) were at the highest frequency. Loudness contours across frequency derived from these measurements are significantly different from in-air measurements with minimum audibility in the 1000 Hz region rather than the 2–4 kHz region observed for in-air measurements.
Interlanguage intelligibility benefit as a function of talker and listener language background and L2 proficiency
Authors: Bent Tessa , Bradlow Ann R.
Published: October 2013

For non-native listeners, intelligibility of non-native speakers (NNS) can surpass intelligibility of native speakers [T. Bent, J. Acoust. Soc. Am. 109, 2472 (2001)]. The present study further investigated how language background and L2 proficiency of talker and listener affect L2 intelligibility. Two Chinese NNS, two Korean NNS, and one English monolingual were recorded reading simple English sentences. Listeners were English monolinguals, Chinese NNS, Korean NNS, and NNS with other L1s. For native English listeners, the native English talker was most intelligible. For non-native listeners, intelligibility of non-native talkers with high degrees of L2 proficiency was better than or equal to native talker intelligibility. This pattern held regardless of whether non-native talkers and listeners matched in L1. Additionally, the interlanguage benefit (i.e., the intelligibility difference between non-native and native talkers) decreased as the listeners’ proficiency in English increased. This interlanguage benefit can be accounted for by a combination of a shared systematic interlanguage (when talker and listener match in L1) and the influence of interlanguage universals (when talker and listener do not match in L1). However, both of these factors become less influential as listeners L2 proficiency develops causing a decrease in the interlanguage benefit. [Work supported by NIH-NIDCD Grant DC 03762.]
Learning to perceive English /d/ versus /ð/: A comparison of French, English, and English–French bilingual 4-year-olds
Authors: Sundara Megha , Polka Linda , Campisi Lisa , Genesee Fred , Marcoux Caroline
Published: October 2013

Recent findings show that discrimination of the English /d–ð/ does not differ for English and French infants (6–8-month-olds and 10–12-month-olds), although English adults clearly outperform French adults on this contrast, which is not phonemic in French. With respect to age effects, English listeners’ perception of /d–ð/ improves between infancy and adulthood, whereas French listeners’ perception remains unchanged [Polka et al., J. Acoust. Soc. Am. 109, 2190–2200 (2001)]. In the present study, we tested monolingual English, monolingual French, and early English–French bilingual 4-year-olds on the same contrast using the same stimuli and procedures to clarify when facilitative effects of language experience emerge and whether they are affected by bilingualism. Four findings are reported. First, a language effect (English>French) is evident by 4 years of age. Second, among native (English) listeners facilitative effects are evident by 4-years of age (infants<4-year-olds<adults). Third, among non-native (French) listeners discrimination performance is comparable across the age groups tested (infants=4-year-olds=adults). Fourth, bilingual 4-year-olds’ performance is virtually identical to that of their French-speaking peers, revealing a strong effect of bilingualism on the perception of this contrast. Several factors contributing to these findings will be discussed.
Listeners’ perceptions of and attitudes toward Hispanic-, Asian-, and Arabic-accented English speakers
Authors: Lass Norman , Atkins Traci , Squires Rebekah
Published: October 2013

A master tape containing the randomized recordings of 20 Hispanic-, Asian-, and Arabic-accented English speakers reading a standard prose passage was presented to a group of 22 native English-speaking listeners who participated in two listening sessions. In the first session they were asked to use a 5-point listening preference rating scale. In the second session they heard the same speakers and were asked to determine the presence or absence of an accent and, if present, the type (Asian, Hispanic, Arabic, or other) and degree (mild, moderate, or severe) of accentedness. A scattergram plotting listeners’ mean listening preference ratings and degree of accentedness ratings for each of the speakers in the study revealed a strong inverse relationship which yielded a statistically significant (p <0.01) correlation coefficient.Thus, the higher the degree of severity of the listeners’ judged accentedness of speakers, the more negative their listening preference rating judgments of the speakers. Implications of these findings and suggestions for future research are discussed.
Duration and F0 cues for vowel length in Japanese
Authors: Kozasa Tomoko
Published: October 2013

Two acoustic cues for the long–short vowel contrast were investigated in productions of Japanese accented vowels under two rates of speech. An accented word has a high–low pitch sequence. Long accented vowels have the fall within the syllable, while short vowels do not. Unsurprisingly, the vowel duration was significantly shorter in fast speech than in slow speech overall. The speech rate affected the long vowel duration more than the short vowel duration; the ratio between short vowels and long vowels varied by speech rate: 1:1.7 in fast speech and 1:1.9 in slow speech. However, the pitch fall was not significantly affected by the speech rate in either type of vowel. These results suggest that for native Japanese speakers, pitch information may be a more stable cue than duration for distinguishing the length of accented vowels. A perception study manipulating these cues is in progress. Synthesized long vowels without the pitch fall characteristic of long accented vowels are compared with normally accented long and short vowels. If Japanese speakers perceive the synthesized vowels as short, this constitutes evidence that for accented vowels, the pitch cue dominates the duration cue.
Perception and production of word-initial long fricatives in Polish
Authors: Thurgood Ela
Published: October 2013

The paper provides an analysis of the perception and production of the Polish distinction between long fricative /v:/ and short fricative /v/ in pre-vocalic position. The task involved 27 native speakers of Polish repeating 50 sentences, including the target sentences. The target sentences were minimal pairs with the meaning difference based solely on fricative length. The results showed that the 190-ms mean duration of the long fricatives was well over twice as long as the 71-ms duration of the short fricatives. When duration of the fricative fell below 147 ms, the listener’s ability to discriminate between a short and long fricative was significantly reduced. Fricative length correlated with the duration of the following vowel: 78% of the time, the vowel was longer in the syllable with the long fricative. Indeterminacy about the identification of long fricatives is particularly well marked in these data: 42% of the responses to prompts with long fricatives included a distinctive pitch pattern, a so-called flat hat: a rising F0 in the first syllable, pitch height maintenance, and a drop after the second syllable. In Polish, this pattern indicates that the speaker is paying particular attention to this part of the utterance [Demenko (1999)].
Recent emphasis of computer modeling in architectural acoustics consulting
Authors: Pyper Ted , Knight Derrick , Schmidt Andrew
Published: October 2013

Jaffe Holden Acoustics has been designing successful performing arts spaces for over four decades. Within recent years, the use of computer modeling programs, such as CATT Acoustic, has gained wide acceptance as a design tool in acoustical consulting. JHA has found computer modeling to be useful in refining some specific design issues. Models will be presented for Zankel Recital Hall at Carnegie Hall, Kennedy Center Concert Hall, Marion Oliver McCaw Hall in Seattle, and the University of Connecticut band rehearsal room. The purpose and application of the models will be discussed, along with the conclusions drawn from each study.
A window on perception: Response times of odontocete cetaceans in audiometric tests
Authors: Blackwood Diane J. , Ridgway Sam H. , Evans William E.
Published: October 2013

A standard psychometric measurement is response time, the interval elapsing between a stimulus and a response. While studies of response time have been published for humans and other terrestrial mammals, this study marks the first report of response times for odontocete cetaceans at threshold in an audiometric task. Two white whales (Delphinapterus leucas) and four Atlantic bottlenose dolphins (Tursiops truncatus) were given audiometric tests to determine masked hearing thresholds. Animals were tested at 26 frequencies over a range from 200 Hz to 100 kHz using pure tones. The test tone amplitudes covered a range of 20 dB re 1 microPascal including the hearing threshold of the animal at that frequency. Hearing thresholds varied from 87.5 dB to 125.5 dB depending on frequency, masking noise intensity and individual animal. Data was analyzed to determine characteristic relationships between response time and amplitude of test tone for each frequency and animal. The two whales responded significantly slower (640 ms, 0.001) than the four dolphins (430 ms). As in terrestrial animals, reaction time became shorter as stimulus strength increased. At threshold, median response time across frequencies within each animal varied about 150 ms.
Accuracy limits on rapid assessment of gently varying bathymetry
Authors: McDonald B. Edward , Holland Charles
Published: October 2013

Accuracy limits for rapidly probing shallow water bathymetry are investigated as a function of bottom slope and other relevant parameters. The probe scheme [B. E. McDonald and Charles Holland, J. Acoust. Soc. Am. 110, 2767 (2001)] uses a time reversed mirror (TRM) to ensonify a thin annulus on the ocean bottom at ranges of a few km from a vertical send/ receive array. The annulus is shifted in range by variable bathymetry (perturbation theory shows that the focal annulus experiences a radial shift proportional to the integrated bathymetry along a given azimuth). The range shift implies an azimuth-dependent time of maximum reverberation. Thus the reverberant return contains information that might be inverted to give bathymetric parameters. The parameter range over which the perturbation result is accurate is explored using the RAM code for propagation in arbitrarily range-dependent environments. [Work supported by NRL.]
The ambiguity of the acoustic source distributions for divergent source fields, with application to aerodynamic noise
Authors: Powell Alan
Published: October 2013

A given uniform applied line force of linear strength F1 falls very rapidly to zero about the ends of its length L1. The wave equation source term is monopolelike, ∂F1/∂y1. The radiation is only from the opposite energy producing monopoles ∫(∂F1/∂y1)dy1=±F1 at its extremities, forming a dipole L1F1. The divergence theorem transforms this into the exactly equivalent dipole distribution of strength F1, total strength F1L1, now the ‘‘obvious’’ energy source for the given excitation. Analogously, a volume L1L2L3 of a quadrupole distribution of uniform strength, say ρu1u2 for an aerodynamic lateral quadrupole, also radiates like opposing line dipoles ∫(∂ρu1u2/∂y2)dy2L3=±ρu1u2L3 along the L1 sides L2 apart (for lateral quadrupole L2ρu1u2L1L3), replaceable by monopoles ∫(∂2ρu1u2/dy1∂y2)dy1 dy2L3 at the corners of the face L1L2 (where ∂2ρu1u2/∂y1∂y2≠0), yielding lateral quadrupole L1L2ρu1u2L3. With exactly the same fields, which can be considered physically realistic, like the force? The situation appears quite ambiguous; although note the fictitiousness of the monopoles, the appeal of ∂ρu1u2/∂y2 appearing in momentum equation as an applied force, while the energy loss by all elements, directly, of the sound producing flow may perhaps be best associated with the quadrupole distribution.
On Weber’s theory of a free reed coupled to a resonator
Authors: Braasch Jonas
Published: October 2013

In the 1820s Wilhelm Weber investigated the effect of resonator length on the frequency of a free reed coupled to a resonator. His aim was to build a device to generate a reference frequency since he was not satisfied with the accuracy of tuning forks. Weber’s goal was to compensate the small dependence of frequency on blowing pressure and temperature by coupling a resonator to the free reed. Besides conducting a series of experiments Weber was the first to formulate a theory to estimate the frequency of a free-reed/resonator system. His theory is based on Euler’s solution for two coupled pendulums with the free reed and the air column of the resonator as the two oscillators. Although some of his assumptions were not quite correct, Weber was able to predict some of the experimental results quite accurately by assuming that the oscillators are synchronized. However, because the free reed by itself was not frequency dependent on blowing pressure and temperature in his theory, he was not able to find a solution for compensating the frequency of the free reed using a resonator. In the presentation Weber’s work will be introduced and compared to present theories.
Measurements of reed vibration and pressure variation of the sho, the Japanese mouth organ
Authors: Hikichi Takafumi , Osaka Naotoshi
Published: October 2013

Measurements of reed vibration and pressure vibration of the sho were carried out. Reed displacement, sound pressure at both sides of the reed, and radiated sound pressure at the open end of the pipe were measured using an experimental sho model made from an acrylic pipe and a metal reed. The kashira, or cavity, was also made from an acrylic box, where the pipe is mounted so that the reed vibration can be measured by a laser displacement sensor. The measurement results show that reeds vibrate as a sinusoidal, and that, in contrast with earlier results obtained by experiments on harmonium reeds [J. P. Cottingham, C. J. Lilly, and C. H. Reed, 137th meeting of the ASA and the 2nd Convention of the EAA, pp. 14–19 (1999)], the amplitude of reed vibration increases with increasing blowing/drawing pressure. The sound pressure inside the tube shows peaks when the reed reaches its maximum displacement, and the sound pressure oscillates twice when the reed oscillates once. Further, sound pressure inside the kashira, i.e., at the upstream of the reed, shows high frequency oscillation compared with reed vibration. This result implies that the shape and volume of the kashira may significantly affect the sound characteristics.
Fast dynamic range compression method for multichannel hearing aids
Authors: Anderson David V.
Published: October 2013

Hearing loss with recruitment results in a frequency-dependent reduced effective dynamic range of the ear. The advance of digital hearing aid capabilities has led to the proliferation of multiband, compression algorithms directed at the recruitment problem. However, results have been mixed at best. We propose an alternative design methodology to designing multiband compressive aids based on attack and release times. In particular, multiband compression hearing aids should be matched to certain characteristics of the ear with a memoryless gain based on the bandlimited envelope function of each band. Under the proposed design method each band has a different effective time-constant.
A novel method of improving sound quality and reducing acoustic feedback in hearing aids
Authors: Killion Mead , French John , Viranyi Steve , Preves David
Published: October 2013

Most current hearing aids have relatively narrow bandwidths, when compared to high-fidelity equipment, and exhibit undamped peaks because the peaks are considered less troublesome than the problem of wax-clogged dampers. Attempting to make hearing aids wider band has typically resulted in increased acoustic feedback problems. The recent availability of an off-the-shelf digital hearing aid integrated circuit amplifier, which contains several biquad filters, when used with special software, automatically detects and suppresses peaks. The filters then further flatten and extend the hearing aid frequency response to 16 kHz, while the appropriate CORFIG correction is added to the frequency response, producing a transparent sound. Open ear versus aided KEMAR recordings were produced using a live jazz trio and a string quartet. The sound quality ratings for eight commercially available digital hearing aids were obtained from several different listening panels. The new response equalization proved advantageous in all cases. The effects of eliminating the peaks in the response on maximum real ear gain achievable before onset of acoustic feedback oscillation will be reported.
Pyroshock testing: Effects of equipment simulators
Authors: Hughes William O.
Published: October 2013

It is critical to a spacecraft’s mission success that flight equipment be properly qualified to its expected shock environment. Simulators of varying fidelity are often used to measure the shock levels during spacecraft shock tests. Pyroshock test data from a recent spacecraft separation test will be shown that illustrates how shock response spectra differ for avionics equipment simulators of both low and high fidelity. The effect of the simulator weight on the shock response will also be shown. Additionally, data showing the attenuation of pyroshock levels, including its reduction with distance and across joints will be discussed. This observed attenuation data generally supports the standard methodologies for predictions of shock attenuation.
Speech perception as complex auditory categorization
Authors: Holt Lori L.
Published: October 2013

Despite a long and rich history of categorization research in cognitive psychology, very little work has addressed the issue of complex auditory category formation. This is especially unfortunate because the general underlying cognitive and perceptual mechanisms that guide auditory category formation are of great importance to understanding speech perception. I will discuss a new methodological approach to examining complex auditory category formation that specifically addresses issues relevant to speech perception. This approach utilizes novel nonspeech sound stimuli to gain full experimental control over listeners’ history of experience. As such, the course of learning is readily measurable. Results from this methodology indicate that the structure and formation of auditory categories are a function of the statistical input distributions of sound that listeners hear, aspects of the operating characteristics of the auditory system, and characteristics of the perceptual categorization system. These results have important implications for phonetic acquisition and speech perception.
T-wave sources, slopes, rough bottoms and continuum
Authors: Odom Robert I. , Soukup Darin J.
Published: October 2013

Bathymetry plays a strong role in the excitation of T-waves by breaking strict mode orthogonality and permitting energy from higher order modes to couple to the lower order modes comprising the T-phase. Observationally (Dziak, 2001) earthquakes with a strong strike-slip component are more efficient at generating T-waves than normal fault mechanisms with the same moment magnitude. It is shown that fault type and orientation correlates strongly with T-wave excitation efficiency. For shallow sources, the discrete modes contribute to the majority of the seismic source field, which is then scattered into the acoustic modes by irregular bathymetry. However, the deeper the earthquake source, the more important the continuum component of the spectrum becomes for the excitation. Deterministic bathymetry and random roughness enter the modal scattering theory as separate terms, and allow the relative contributions from the slope conversion mechanism and bottom roughness to be directly compared. [Work supported by the National Ocean Partnership Program.]
Sediment tomography in the East China Sea: Compressional wave speed and attenuation inversions from mode travel time dispersion and Airy phase measurementsa)
Authors: Lazauski Colin J. , Potty Gopu R. , Miller James H. , Chen Chuen-Song , Dahl Peter H.
Published: October 2013

This paper discusses ongoing data analysis results from the acoustic bottom interaction experiment conducted in May–June 2001 in the East China Sea as part of the Asian Seas International Acoustics Experiment (ASIAEX-2001). Using time-frequency scalograms of broadband signals, the modal arrivals and group speed minimums (Airy Phase) of several modes are clearly observed. The structure of the Airy Phase signal forms the basis of this inversion technique. Utilizing the Airy Phase group speed minimums and corresponding pressure amplitudes of each observable mode, the sediment compressional wave speed and attenuation as a function of depth are derived. The group speed minimum for each mode provides additional information on the compressional wave speed in the modal sediment depth penetration interval. Inverted speeds and estimated modal penetration depths are then used to develop the sediment profile. The estimated resolution is dependent on the number and frequency span of the observable modes. This method has the advantage of utilizing only one hydrophone to obtain rapid estimates of sediment properties. Additionally, it also complements other inversion schemes that can benefit from accurate a priori environmental information by limiting the size of the search parameter space. Estimated sediment properties from several areas are presented with verification from coring results. [Work supported by ONR.] a)For Acoustical Oceanography Best Student Paper Award.