bluuebunny/crossref_metadata_2025 huggingface dataset:
Popular papers with short case stories on acoustics and vibration for practical engineers and students
Authors: Vinokur Roman
Published: May 2013

One of the reasons for using foam wedges or cones in hemi-anechoic rooms is a gradual change of the acoustical impedance in order to reduce the reflection of incident sound waves from the sound absorbing walls. By analogy, popular papers on science (in particular, in acoustics and vibration) facilitate a smooth introduction to new theories because of their small cognitive “impedance” to understanding the written information. Such papers are relevant mostly for extramural reading but they help engineers and students to promptly perceive important effects and applications via interesting case stories and simplified physics and mathematics. Generally speaking, this approach is not new: in particular, it was successfully applied by Perelman in his book “Physics for Entertainment.” But in author’s opinion, for better effectiveness such texts should be limited in size and include 3–4 related short case stories from actual engineering or consulting practice, history, news, or literature. To illustrate this method, several one-page papers published in the “Sound and Vibration” magazine will be briefly discussed: “Vibroacoustic Measurements without Transducers,” “A Common Myth about Mechanical Resonance,” “Only the Best Will Do,” and “Haunted Buildings and Other Acoustical Challenges.”
Mechanical bent-type models of the human vocal tract consisting of blocks
Authors: Arai Takayuki
Published: May 2013

In our previous work, we developed several physical models of the human vocal tract and reported that they are intuitive and helpful for students studying acoustics and speech science. Models with a bent vocal tract can achieve relatively realistic tongue movements. These bent-type models had either a flexible tongue or a sliding tongue. In the former case, the tongue was made of a flexible gel-type material so that we could form arbitrary tongue shapes. However, this flexibility meant that training is needed to achieve target sounds. In the latter case, the tongue was made of an acrylic resin, and only a limited number of vowel sounds can be achieved because so few sliding parts are available to change the tongue shape. Therefore, in this study, we redesigned the mechanical bent-type models so that they now consist of blocks. By placing the blocks at the proper positions, the block-type model can produce five intelligible Japanese vowels. We also designed a single bent-type model with sliding blocks that can produce several vowel sounds. [This work was partially supported by a Grant-in-Aid for Scientific Research (24501063) from the Japan Society for the Promotion of Science.]
Human ability of counting the number of instruments in polyphonic music
Authors: Stöter Fabian-Robert , Schoeffler Michael , Edler Bernd , Herre Jürgen
Published: May 2013

There are indications that humans are only able to correctly count up to three voices in polyphonic music pieces of homogeneous timbre, where each voice is played by the same instrument. A more general case, where voices are played by instruments of inhomogeneous timbre, has not been fully addressed so far. In order to approach this question we conducted a listening experiment with 62 participants to find out whether both scenarios — instrumentation by inhomogeneous or homogeneous timbre — share the same outcome. This paper describes the design of the experiment including an analysis of the results, which show that both scenarios are related. Furthermore, a detailed analysis of the error rates in correctly counting the number of instruments reveals that there are significant differences between non-musician and musician listeners, in particular regarding the upper auditory limit of the number of correctly counted instruments. Based on these results, models for the perception of instruments in auditory streams can be developed.
Effects of audio latency in a disc jockey interface
Authors: Simon Laurent S. , Vimond Arthur , Vincent Emmanuel
Published: May 2013

This study presents an evaluation of the disturbance caused by audio latency in a DJ-ing task. An experiment was conducted, during which subjects were asked to synchronize one piece of music to a reference piece of music using a common DJ-ing interface. Synchronization was performed by adjusting the speed of one of the music pieces to that of a reference piece of music and time-aligning both pieces. Latency was introduced between the interface and the audio output, varying between 0 and 550 ms. The average synchronization time was estimated as a function of subjects, beat-per-minute difference between the pieces of music, and latency. Results showed that for trained DJs, synchronization time increased significantly above 130 ms of audio latency, whereas for naive subjects, latency had no influence on the synchronization time.
Real-time concatenative synthesis for networked musical interactions
Authors: Alexandraki Chrisoula , Bader Rolf
Published: May 2013

The recent proliferation of Networked Music Performances has led to the investigation of low-latency, low-bitrate musical encoding schemes, including audio codecs and control protocols that specifically address the requirements of live musical interactions across the Internet. This work presents an alternative perspective inspired by the “synthesis by analysis” approach, tightly constrained in terms of processing latencies and rendering quality. The entire process is fully automated and involves an offline processing phase (that takes place prior to performance) and an online real-time analysis-synthesis phase. The offline phase involves processing a solo recording of each musician’s part so as to acquire (a) audio segments corresponding to each note in the performance, and (b) a trained Hidden Markov Model to be later used for online analysis. During live performance, the online analysis process encodes the position of the performance on a music score and re-synthesizes the audio waveform by concatenating the audio segments of the offline phase. Although the synthesized waveform originates from an offline solo recording, it is synchronized to the live performance at note level, so as to allow for rendering a wide range of musical tempi as well as their expressive variations. The paper presents the complete methodology and reports on implementation details and preliminary evaluation results.
A flight research overview of the Waveforms and Sonicboom Perception and Response Project, the National Aeronautics and Space Administration's pilot program for sonic boom community response research
Authors: Cliatt Larry J. , Haering Edward A. , Holtz Michael D. , Jones Thomas P. , Waggoner Erin R. , Wiley Scott L. , Parham Ashley K. , Houtas Franzeska F.
Published: May 2013

To support the National Aeronautics and Space Administration’s (NASA) ongoing effort to bring supersonic commercial travel to the aerospace industry NASA Dryden, in cooperation with other government and industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale sonic boom community human response test. The name of the project was Waveforms and Sonicboom Perception and Response (WSPR). Such tests go toward building a dataset that governing agencies like the Federal Aviation Administration and International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. This paper focuses on NASA’s role in the project on essential elements of community response testing including recruitment, survey methods, instrumentation systems, flight planning, and operations. Objectives of the testing included exposing a residential community with sonic boom doses designed to simulate those produced by the next generation of commercial supersonic aircraft. The sonic booms were recorded with an instrumentation array that spanned the community. Human response data was collected using multiple survey methods, and was correlated to acoustic metrics from the sonic booms. The project resulted in lessons-learned and the findings of appropriate methods necessary to implement a successful large-scale test.
Relationships among near-real time and end-of-day judgments of the annoyance of sonic booms
Authors: Fidell Sanford , Horonjeff Richard , Fidell Linda
Published: May 2013

A recent social survey of the annoyance of low amplitude sonic booms included both prompt and delayed-response questions about the annoyance of sonic booms heard by respondents in the home over the course of two weeks. Interviews were conducted via smartphone with 49 voluntary test participants. Most of the prompt annoyance judgments were made within about a minute of notice of a sonic boom. The delayed response judgments were solicited in the evening, at a time of the respondent’s choosing. Prior analyses showed that dosage-response relationships between the prevalence of high annoyance and sonic boom amplitude were well predicted by CTL analysis. The current analyses investigated how individual, within-day, prompt annoyance judgments were related to end-of-day judgments of the annoyance of sonic booms. Preliminary analyses suggest that end-of-day annoyance judgments are not simply a linear sum or averaging of the annoyances of individual sonic booms.
Effect of room characteristics on perception of low-amplitude sonic booms heard indoors
Authors: Giacomoni Clothilde , Davies Patricia
Published: May 2013

Supersonic flight over inhabited territories of the United States has been banned by the Federal Aviation Association. While research has been conducted to determine the effects of sonic booms on the general population when heard outdoors, little work has been done on people’s perception of sonic booms as heard indoors. A sound’s waveform will change in its transmission from outdoors to indoors due to several factors, one of which is the indoor acoustic environment. This can be changed using different room sizes, shapes or which materials are covering each surface (wall, ceiling, or floor). A subjective test, designed to determine which of these room characteristics has an effect on people’s ratings of annoyance, has been completed. It was found that smaller rooms and square rooms are rated as more annoying than larger rooms or rooms with a corridor-like or rectangular shape, and that rooms with lower reverberation times were rated as less annoying than rooms with higher reverberation times.
Characterizing the soundscape of tranquil urban spaces
Authors: De Coensel Bert , Boes Michiel , Oldoni Damiano , Botteldooren Dick
Published: May 2013

Tranquil spaces provide restorative environments for urban residents and visitors and are therefore essential for health and quality of life. Tranquil spaces may be characterized through a combination of acoustical criteria, such as relatively low (percentile) sound levels and the relative absence of non-fitting sounds, and non-acoustical criteria, such as the presence of natural elements within the visual scene. Public urban parks and courtyards as well as private urban backyards are typically considered to be the most tranquil spots within a city. Current state-of-the-art in distributed measurement technology allows for long-term sound monitoring at these places. In this paper, the soundscape at a number of urban parks and backyards in the cities of Ghent and Antwerp is investigated through a detailed analysis of sound measurements performed over an extended period of time. An analysis of percentile sound levels, noise events and indicators for temporal and spectral structure is presented, and novel computational methods are applied to estimate the relative occurrence of sounds arising from various sources.
On the noise generated by park visitors along hiking trails
Authors: Newman-Johnson Lucas , Schomer Paul D.
Published: May 2013

In assessing the sound environment of a park, visitor noise along trails may be important because of its affect upon: (1) the un-altered park environment, (2) wildlife, and (3) other park visitors. Just as noise in residential communities has been correlated with population density we set out to see if the noise level along trails would correlate with visitor density. In the summer of 2011, measurements were made using two sites, one on each of two trails. These measurements included one second Leq measurements at an array of four trailside microphones, and recording of the number of park visitors entering the measurement zone during each minute. Examination of the data revealed little correlation between a 5 min measurement of the Leq and density of trail visitors. The problem was that the smallest time increment in which we could accurately portray the number of park visitors was about 5 min, using the one minute totals, and in a 5 min period visitor noise would rarely equal or exceed the measurement ambient. Thus, no relation between visitor density and trailside noise could be developed. Additional analysis was done with data to better understand the limiting factors to the measurement.
Probing acoustics of liquid foams by optical diffusive wave spectroscopy
Authors: Dollet Benjamin , Erpelding Marion , Guillermic Reine-Marie , Sample Caitlin , Pierre Juliette , Saint-Jalmes Arnaud , Crassous Jérôme
Published: May 2013

Sound propagation through liquid foams, which are dispersions of gas bubbles in a continuous liquid phase, is not well known yet. To characterize foam acoustics at the local scale, we have studied the effect of an external acoustic wave on bubble displacements inside an aqueous foam. We quantify these displacements by using a technique based on optical diffusive wave spectroscopy, that we specially developed to resolve tiny deformations in materials. Bubble displacements induce a modulation on the photon correlation curve. Measurements for various sound frequencies and amplitudes are interpreted using a light diffusion model. It allows us to unravel a nontrivial acoustic displacement profile inside the foam; in particular, we find that the acoustic wave creates a localized shear in the vicinity of the solid walls holding the foam, as a consequence of inertial contributions. This study of how bubbles “dance” inside a foam as a response to sound turns out to provide new insights on foam acoustics and sound transmission into a foam, foam deformation at high frequencies, and analysis of light scattering data in samples undergoing nonhomogeneous deformations.
Negative and density-near-zero acoustic metamaterials based on quasi-two-dimensional phononic crystals
Authors: Garcia-Chocano Victor Manuel , Graciá-Salgado Rogelio , Torrent Daniel , Sánchez-Dehesa José
Published: May 2013

A phononic crystal consisting of an array of cylindrical boreholes in a two dimensional waveguide has been fabricated and characterized. Reflectance and transmittance have been measured in a slab with seven layers of scatterers. The acoustic bands as well as the effective parameters have been extracted from experimental data, showing that the proposed structure behaves as an acoustic metamaterial with negative bulk modulus. In addition it is shown that the inclusion of anisotropic effects through angular-dependent structures inside the boreholes leads to metamaterials with double negative parameters. This feature allows the observation of interesting phenomena such as an acoustic tunneling, which has been predicted through full wave simulations in a density-near-zero metamaterial.
Brain activity and perception of gaze-modulated tinnitus
Authors: Van Dijk Pim , Van Gendt Margriet J. , Boyen Kris , De Kleine Emile , Langers Dave R.
Published: May 2013

We studied the correspondence between brain activity and tinnitus in subjects with gaze-modulated tinnitus. These subjects are able to modulate their tinnitus by peripheral gaze of the eyes. This is a rare form of tinnitus that primarily occurs in subjects that underwent acoustic schwannoma surgery. The voluntary control of the tinnitus allows for a controlled experiment to study the perceptual characteristics of tinnitus and the corresponding brain activity as assessed by functional MRI. Eighteen subjects with gaze-modulated tinnitus participated in the study. The effect of gaze on tinnitus was diverse. Most commonly, the largest effect on tinnitus was observed for horizontal gaze toward the surgery side. When the loudness of tinnitus changed, it was usually an increase. In addition, changes of the pitch and apparent bandwidth of the tinnitus were reported. Peripheral gaze corresponded to increase of activity in the cochlear nucleus and inferior colliculus, a decrease of activity in the medial geniculate body, and a reduction of deactivation in the auditory cortex. The inhibition of the medial geniculate body in the thalamus contrasts with the excitation that is typically observed in response to external sound stimuli. It suggests that abnormal functioning of the thalamus plays a role in tinnitus.
Noise-induced hearing loss and strategies for its prevention in the New Zealand population: The Kiwi connection
Authors: Thorne Peter R. , Coad Gavin , Reddy Ravi , Welch David
Published: May 2013

Celebrating Glenis Long’s outstanding contribution to auditory physiology and psychoacoustics, this presentation covers the New Zealand connection and particularly her involvement in our research program into the monitoring and prevention of noise-induced hearing loss (NIHL) in the country. A large multidisciplinary project is being undertaken to investigate the nature of occupational hearing loss in New Zealand and establish a national approach to prevent NIHL. This includes estimates of NIHL prevalence and the design and evaluation of education and prevention programs to reduce the impact of noise. Using a modeling approach, we have estimated that NIHL contributes to 17–25% of cases of hearing impairment in New Zealand and is therefore a significant modifiable risk factor. A key component of our project is monitoring of noise injury and we have also studied distortion product otoacoustic emissions (DPOAE) as a measure of early injury. To assess DPOAEs as a measure of injury, we recorded them using swept pure tones and extracted DPOAE components using a least-squares fit approach in noise and non-noise exposed individuals. OAE findings were compared with measures of auditory function. We found that the generator component correlated more strongly with auditory threshold and thus may be a better physiological index of noise injury. Overall, these findings have informed a national strategy involving government and community agencies to mitigate the effects of noise.
Factors affecting frequency discrimination in school-aged children and adults
Authors: Taylor Crystal N. , Buss Emily , Leibold Lori J.
Published: May 2013

Auditory frequency discrimination is a basic ability that may limit the maturation of speech and language skills in some listeners. Despite its importance, the factors affecting frequency discrimination in school-aged children are poorly understood. The goal of the present study was to evaluate effects related to memory for pitch, musical training, and the utilization of temporal fine-structure cues. Listeners were normal-hearing children, 5.1–13.6 years old, and adults. One subgroup of children had musical training (>150 h) and the other did not. The standard stimulus was either a 500- or a 5000-Hz pure tone, and the target stimulus was either a tone of higher frequency or a frequency-modulated tone (2- or 20-Hz rate) centered on the standard frequency. As commonly observed, mean frequency discrimination thresholds tended to be elevated in younger listeners. This developmental effect was smaller for FM detection than for pure-tone frequency discrimination, consistent with an effect of memory for pitch. The child/adult difference tended to be smaller for musically trained than untrained children. Children were not particularly poor at 2-Hz FM detection for the 500-Hz standard, a condition thought to rely on temporal fine-structure cues. [Work supported by NIDCD R03DC008389.]
Cognitive and auditory influences on speech recognition by younger, middle-aged, and older listeners
Authors: Helfer Karen S. , Costanzi Angela
Published: May 2013

In this study, we measured hearing thresholds and cognitive abilities (working memory, processing speed, executive function, and inhibition) in our participants to determine how these factors relate to speech understanding in the presence of competing speech. Participants were younger, middle-aged, and older adults, with the older adults having hearing thresholds that ranged from normal to a moderate hearing loss. The target stimuli for this study were recordings of TVM sentences [Helfer and Freyman (2009)] presented with various types of maskers (one or two other TVM sentences spoken by same-sex maskers, samples of running speech spoken by one or two same-sex talkers, and single-channel signal-envelope-modulated noise) at several signal-to-noise ratios. This poster will discuss speech recognition performance in the framework of multimasker penalties and will detail connections among hearing thresholds, cognitive abilities, and speech understanding. [Work supported by NIH DC012057.]
Intelligibility of voiced and whispered speech in noise in listeners with and without musical training
Authors: Ruggles Dorea , Riddell Ariane , Freyman Richard , Oxenham Andrew J.
Published: May 2013

Musicians have been shown to exhibit more robust neural coding of periodicity than non-musicians; they have also been reported to exhibit an advantage in understanding speech in noise. This study tested the hypothesis that the musicians’ speech intelligibility advantage arises from more efficient coding of voiced (periodic) speech. This was tested by comparing intelligibility of normal speech in noise with that of whispered (unvoiced) speech in musicians and non-musicians. Listeners with less than 2 years of formal musical training were categorized as non-musicians; listeners who began musical training before age 10 and who currently play more than 10 h/wk were included as musicians. Listeners heard grammatically correct nonsense sentences that were either (1) voiced, (2) whispered, or (3) whispered with subband amplitude distributions matched to the voiced speech. Masking noise was either continuous or gated with a 16 Hz, 50% duty cycle. In contrast to the earlier study, preliminary data suggest no advantage for musicians over non-musicians in understanding voiced or whispered speech in either continuous- or gated-noise conditions. The results suggest that more investigation is needed to fully understand the nature of auditory and speech processing advantages imparted by musical training. [Wok supported by NIH Grant No. R01DC05216.]
Binaural speech recognition in continuous and intermittent noises in people with hearing loss
Authors: Laroche Chantal , Roveda Jean-Grégoire , Levionnois Julie , Giguère Christian , Vaillancourt Véronique
Published: May 2013

Multiple tests have been developed to quantify speech recognition in noise, but the characteristics of the masking noise vary significantly across tests and can considerably impact performance and clinical interpretation. Using the HINT, speech perception in 24 young adults with normal hearing was assessed using both the standard masker (a continuous speech-spectrum noise) and an intermittent version of the masker at an ON-OFF rate of 16 Hz. Intermittency helps in extracting speech from the “quiet” segments of the noise. Speech recognition thresholds for frontal speech were better in the intermittent than the continuous noise by an amount of 13 and 10 dB for noise maskers located in front or side, respectively, The average difference in thresholds between the noise front and side conditions, called the binaural advantage, was 4.7 and 8.4 dB for the intermittent and continuous noises, respectively. Data collected with people presenting different hearing loss profiles also show binaural and intermittency advantages, but to a lesser degree. Considering that people encounter a wide a range of fluctuating noises in daily life, these results motivate adding an intermittent noise condition to the HINT protocol to better reflect the challenges faced by individuals with hearing loss.
Spatial release from masking for noise-vocoded speech
Authors: Swaminathan Jayaganesh , Mason Christine R. , Streeter Timothy M. , Best Virginia , Kidd, Jr Gerald
Published: May 2013

Spatially separating a speech target from interfering masker(s) generally improves target intelligibility; an effect known as spatial release from masking (SRM). This study assessed the contribution of envelope cues to SRM. Target speech was presented from the front (0° azimuth) and speech maskers were either colocated or symmetrically separated from the target in azimuth (±15°, ±30°, ±45° and ±90°) using KEMAR head-related transfer functions. The target and maskers were presented either as natural speech or as noise-vocoded speech. For the vocoded speech, intelligibility was conveyed only by the envelopes from M frequency bands. Experiment 1 examined the effects of varying the number of frequency bands for the vocoder, and the degree of target-masker spatial separation, on SRM. Experiment 2 examined the effects of low-pass filtering the envelopes of the vocoded speech bands on SRM. Preliminary results for experiment 1 indicated that SRM improved as the number of spectral channels providing independent envelope cues increased for all spatial separations. Preliminary results for experiment 2 showed no difference in SRM between low and high envelope-frequency cutoffs. Potential implications for studying hearing-impaired and cochlear-implant subjects will be discussed. [Work supported by NIH-NIDCD and AFOSR.]
Annoyance perception for hearing impaired listeners: A revisit
Authors: Valentine Susie , McKinney Martin , Zhang Tao
Published: May 2013

For hearing impaired (HI) listeners, it is well known that certain sounds are much more annoying than others even though they may have similar spectral shape and level. For example, HI listeners often report paper rustling noise as highly annoying. A common approach to deal with this complaint is to reduce high frequency gain. While this approach may mitigate the complaint, it can create audibility issues for speech. A more effective approach is to determine the underlying cause of annoyance and then design an algorithm to selectively reduce it. While existing literature on annoyance perception for HI listeners is scant, a previous attempt was made to investigate this perception using real-world recordings [Vishnubhotla et al. (2012)]. The study showed a large variability of annoyance ratings across listeners that may have been due to subjective associations with the sound sources. In this study, we use abstract psychoacoustic stimuli designed carefully to avoid possible confounding subjective associations. A magnitude estimation method was used to measure the annoyance of each stimulus in hearing impaired listeners. All stimuli were presented over headphones in a sound treated room. Results will be presented along with implications for hearing aid applications.
Spatial release from masking in simulations of cochlear implants for single-sided deafness
Authors: Bernstein Joshua G. , Iyer Nandini , Brungart Douglas S.
Published: May 2013

Previous studies have shown that single-sided-deaf (SSD) patients implanted with cochlear implants (CIs) can receive spatial release-from-masking (SRM), likely due to head-shadowing effects. This study investigated the possibility that SSD-CI patients might also obtain SRM benefits from binaural-integration cues when the target speech is masked by a spatially separated fluctuating masker. Experiment 1 measured psychometric functions for word-recognition performance in the presence of stationary noise, modulated noise, and one or two same- or opposite-gender interfering talkers. The first ear received an unprocessed mixture containing the target and masker(s). The second ear received no signal (SSD), an unprocessed mixture containing just the maskers (NH-Binaural), or a mixture containing just the maskers that was processed with an eight-channel noise vocoder (SSD+CI). The results show that SRM occurs in the NH-Binaural condition for all masker types, but that it only occurs in the SSD+CI condition with same-gender interfering talkers. Experiment 2 revealed that SRM occurred in the SSD+CI condition with as few as two vocoder channels, and that maximum performance occurred with six or more channels. These results suggest that CIs for SSD have the potential to produce SRM in situations where monaural cues are insufficient for concurrent speech-stream segregation.
Speech intelligibility of hearing impaired participants in long-term training of bone-conducted ultrasonic hearing aid
Authors: Matsui Toshie , Shimokura Ryota , Nishimura Tadashi , Hosoi Hiroshi , Nakagawa Seiji
Published: May 2013

Bone-conducted ultrasonic hearing aid (BCUHA) system is the unique device to provide the auditory sensation to profoundly hearing-impaired persons without any surgical operations. To clarify effects of long-term hearing training with this device, two deaf participants engaged the BCUHA training for 9 months. They were trained to use BCUHA through repetition of sentences read aloud and free conversation, and then they took part in word recognition tests and monosyllabic identification tests. Both participants showed that they could recognize words above chance using auditory sensation only provided by BCUHA device if alternatives or context were presented to them during the trials. Besides, it was observed that monosyllabic intelligibility score with both of auditory and visual cue had much increased with the day of training than the score with auditory cue only and that with visual cue only. The result suggests that the long-term training with BCUHA achieves efficient integration of auditory and visual cue of speech such as cochlear implant users showed in previous studies.
Recollections of my father: Miguel C. Junger
Authors: Junger Sebastian
Published: May 2013

Thoughts and reflections on my father as such an inspirational and unforgettable person.
Miguel Junger: Legacy contributions to the field of structural acoustics
Authors: Feit David
Published: May 2013

The field of structural acoustics, i.e., the theory of acoustic radiation and scattering from elastic structures, developed primarily in the last half of the 20th century in response to Navy needs. Miguel Junger and colleagues at Cambridge Acoustical Associates under the sponsorship of the Office of Naval Research Sound and Structures made seminal contributions to the field. This presentation reviews some of this research, which ultimately was included in the book, “Sound, Structures and Their Interaction.”
Acoustic waves in violently collapsing bubbles
Authors: Geers Thomas L.
Published: May 2013

Among Miguel Junger’s many contributions to acoustical science and engineering were his papers and presentations on bubble acoustics. Among his many contributions to the well being of his colleagues at Cambridge Acoustical Associates was the mentoring of this presenter during the latter years of graduate study at MIT. Hence, this presentation in this session. In an evaluation of five reduced models for spherically symmetric bubble collapse and rebound [J. Appl. Phys. 112, 054910 (2012)], it was found that some recent models, which incorporate wave propagation in both the external fluid and internal gas, did not perform as well as the long-established model by Keller and Kolodner, which incorporates wave propagation in the fluid but not in the gas [J. Appl. Phys. 27, 1152–1161 (1956)]. Performance was assessed through comparisons against response histories produced by finite-difference solution of the Euler equations under adiabatic conditions. Further investigation revealed that neither acoustic-wave nor shock-wave propagation in the gas was apparent, but that a standing wave in the gas was. This prompted an enhancement of the Keller and Kolodner model that accounts for the standing wave. The formulation and evaluation of the enhanced model is the subject of this presentation.
Sound radiation from finite surfaces
Authors: Brunskog Jonas
Published: May 2013

A method to account for the effect of finite size in acoustic power radiation problem of planar surfaces using spatial windowing is developed. Cremer and Heckl presents a very useful formula for the power radiating from a structure using the spatially Fourier transformed velocity, which combined with spatially windowing of a plane waves can be used to take into account the finite size. In the present paper, this is developed by means of a radiation impedance for finite surfaces, which is used instead of the radiation impedance for infinite surfaces. In this way, the spatial windowing is included in the radiation formula directly, and no pre-windowing is needed. Examples are given for the radiation efficiency, and the results are compared with results found in the literature.
Processing speech of varying intelligibility
Authors: Smiljanic Rajka , Chandrasekaran Bharath
Published: May 2013

In this talk, we examine how variation in intelligibility impacts speech processing with insights from behavioral and neuroimaging studies. We discuss a set of experiments that explore the extent to which listener-oriented speaking style changes, sentence context, and visual information contribute to enhanced word recognition in challenging listening conditions. We further examine whether these same enhancements impact speech processing beyond word recognition, namely recognition memory for sentences. The results show that both signal-related and contextual enhancements lead to improved speech recognition in noise and, crucially, to a substantially better sentence recall. We then discuss studies examining neural mechanisms involved in processing speech of varying intelligibility using fMRI. Previous fMRI studies have examined speech intelligibility by using artificially degraded speech stimuli. Few studies have examined natural variation in intelligibility. Here we present neuroimaging data from two studies that examine natural variations in speech intelligibility (native vs. non-native speech; audio versus audiovisual speech). Overall, combined insights from behavioral and neuroimaging studies provide important additions to our understanding of how different sources of variability in the speech signal affect speech processing and memory representations.
The impact of variation in phoneme category structure on consonant intelligibility
Authors: Hazan Valerie , Romeo Rachel R. , Pettinato Michele
Published: May 2013

Newman et al. [J. Acoustic. Soc. Am. 109, 1181–1196 (2001)] suggested that phoneme identification accuracy and speed for a given talker was affected by the degree of variability in their production of phoneme categories. This study investigates how intra-talker variability in the production of two phoneme contrasts varies with age and gender, and how this variability affects speed of perceptual processing. Multiple iterations of tokens differing in initial consonants (/s/-/∫/, /p/-/b/) were collected via picture elicitation from 40 adults and 31 children aged 11 to 14; measures of within-category dispersion, between-category distance, overlap, and discriminability were obtained. While females produced more discriminable categories than males, children produced farther yet more dispersed—and thus similarly discriminable—categories than adults. Variability was contrast-specific rather than a general talker characteristic. Tokens with initial /s/-/∫/ from pairs of adult and child talkers varying in between-category distance or overlap were presented for identification. The presence of overlap had a greater effect on identification accuracy and speed than between-category distance, with strongest effects for adult speakers, but reaction time correlated most highly with within-category dispersion. These data suggest that talkers who are less consistent in their speech production may be perceived less clearly than more internally consistent talkers.
Development of the auditory evoked potential to amplitude rise time and rate of formant transition of speech sounds
Authors: Shahin Antoine , Carpenter Allen
Published: May 2013

We investigated the morphology of the N1-P2 auditory evoked potential (AEP) to changes in amplitude rise time (ART) and rate of formant transition (RFT) of consonant-vowel pairs (CVs) in 4–6-year olds and adults. In the AEP session, individuals listened passively to the CVs /ba/, /wa/, and a /ba/ with a superimposed slower-rising /wa/ envelope (/ba/wa). In the behavioral session, individuals listened to the same stimuli and judged whether they heard a /ba/ or /wa/. In 6-year olds and adults, the N1-P2 amplitude reflected a change in RFT (/ba/wa and /wa/) but not in ART (/ba/ and /ba/wa). In contrast, in the 4–5-year olds, the poorly developed N1-P2 did not show specificity to changes in RFT or ART. Behaviorally, 6-year olds and adults relied more strongly on RFT cues (classified /ba/wa as /ba/) during phonetic judgments, as opposed to 4–5-year olds, which utilized both cues equally (chance level). Our findings suggest that following age 4–5, the development of the N1-P2 AEP, representing maturation of synaptic connections in the superficial layer of the auditory cortex, reflects a shift toward weighting of spectral dynamics more than amplitude dynamics during /ba/ - /wa/ phonetic categorization.
Speech understanding in babble noise and syllabic-range temporal processing in aging
Authors: Divenyi Pierre
Published: May 2013

The ability to understand speech in multitalker noise was measured in a group of 46 elderly (71.6 +/− 6.03 years) having at worst moderate presbycusic hearing loss, using the SPIN test with the target and an 8-talker babble presented either monaurally (left or right) or, using generic HRTF spatialization, with the target at 45 degrees right or left flanked by two independent 4-talker babble on each side. The subjects’ temporal processing was measured as (1) the reverberation time yielding a 15% decrease in word comprehension and (2) as the minimum modulation index necessary to segregate two streams generated by modulating, at an average frequency of 4.375 Hz, two carriers consisting of harmonics 4, 5, and 6 having fundamental frequencies of 107 and 189 Hz, that produced two simultaneous three-pulse envelopes, one accelerating and one decelerating. With effects of hearing loss under control, the data exhibited correlations between intelligibility in babble and temporal processing that were significant for a speech-to-babble ratio of 4 dB but not for one of 8 dB. The results thus suggest that under unfavorable acoustic conditions the elderly achieve speech understanding by focusing on prosodic rhythm on the syllabic level. [Work supported by NIA and the VA Medical Research.]
Perceptual confusability of French vowels
Authors: Hall Kathleen C. , Hume Elizabeth
Published: May 2013

The confusability of sounds is argued to both reflect phonological structure [e.g., Boomershine et al. (2008)] and be a source of phonological variability and change [e.g., Ohala (1981), Hume (1998)]. We present the results of a perception task in which 25 Parisian French-speaking participants identified the French vowels [i e ɛ y o/ œ ə a u o ɔ ɔ̃ ɛ̃ ɑ̃], or ∅, in an aC_Ca context, using standard orthography in key words. The durations of the vowel in the vowel-containing stimuli were manipulated to be 0, 15, 25, 50, or 100% of their original durations. We can therefore determine which vowels are most confusable with each other (and thus likely to be the target for either mergers or dissimilatory processes) and which are most confusable with zero (and thus likely to be the target of processes such as deletion, assimilation, and metathesis). Results show high accuracy for [a i y u], even with very short durations; some degree of confusability within the nasal vowels; high confusability rates within the mid-front rounded vowels; and a tendency for zero to be confused with one of the mid-front rounded vowels. These results align with observed phonological patterns in French.
When spectral smearing can increase speech intelligibility
Authors: Bashford James A. , Warren Richard M. , Lenz Peter W.
Published: May 2013

Sentences were reduced to an array of 16 effectively rectangular bands (RBs) having center frequencies ranging from 0.25 to 8 kHz spaced at ⅓-octave intervals. Four arrays were employed, each having uniform subcritical bandwidths which ranged from 40 to 5 Hz. The 40 Hz width array had intelligibility near ceiling, and the 5 Hz array about 1%. The finding of interest was that when the subcritical speech RBs were used to modulate RBs of noise having the same center frequency as the speech, but having bandwidths increased to a critical (ERBn) bandwidth at each center frequency, these spectrally smeared arrays were considerably more intelligible in all but the 40 Hz (ceiling) condition. For example, when the 10 Hz bandwidth speech array having an intelligibility of 8% modulated the ERBn noise array, intelligibility increased to 48%. This six-fold increase occurred despite the elimination of spectral fine structure and the addition of stochastic fluctuation to speech envelope cues. (As anticipated, conventional vocoding with matching bandwidths of speech and noise reduced the 10-Hz-speech array intelligibility from 8% to 1%.) These effects of smearing confirm findings by Bashford, Warren, and Lenz (2010) that optimal temporal processing requires stimulation of a critical bandwidth. [Work supported by NIH.]
Ambiguity related to French liaisons: The role of bottom-up and top-down processes
Authors: Babineau Mireille , Shi Rushen
Published: May 2013

French liaison is a phonological process involving the surfacing of an underlying floating consonant as the onset of a vowel-initial word when the word is preceded by a liaison-causing word. We used vowel- and consonant-initial ambiguous targets following four liaison-related contexts /z/, /n/, /t/, /r/ (e.g., ces onches - ces zonches). Targets included nouns and pseudo-nouns. Quebec-French-speaking adults performed two tasks (production, discrimination). One bottom-up (acoustic cues) and three top-down (noun token frequency, word onset probability, contextual liaison knowledge) factors were investigated in the production task. Participants had to produce the last word upon hearing each phrase. Their productions thus reflected their interpretation of the onset of the liaison-ambiguous words. Perception of acoustic cues was also tested in the discrimination task: participants judged if two phrases were different or same. No perception of any acoustical distinction was revealed in the tasks: participants often produced the intended target incorrectly, and differently intended phrasal pairs were judged same (e.g., ces onches - ces zonches). Effects of top-down information were found in the production task. Among the top-down factors, liaison knowledge related to liaison-causing words had a dominant impact on participants’ interpretation of the ambiguous phrases, showing the importance of contextual knowledge in lexical recognition.
The identification of high pass filtered vowels
Authors: Donai Jeremy , Paschall Dwayne
Published: May 2013

Vowels are typically described according to their spectral prominences (i.e., formants). Previous studies have shown that the first three formants provide important information for identification (Hillebrand et al. (1995), Miller (1989), Molis (2005), Peterson and Barney (1952)]. The present study measured identification accuracy for six naturally produced vowels spoken by a male and female talker with these spectral prominences removed. The six hVd tokens for each talker were high-pass filtered to remove the first three formants from the vowels and then identified by 24 normal hearing listeners. Results suggest that listeners identified a majority of the tokens above chance levels. The average identification of the male vowels was 29% (range, 17%–47%), with two vowels identified with nearly 50% accuracy. Average identification for the six female vowels was 53% (range, 37%–72%), with 5 of 6 vowels being identified with over 40% accuracy.
The role of across-frequency envelope processing for speech intelligibility
Authors: Chabot-Leclerc Alexandre , Jo/rgensen So/ren , Dau Torsten
Published: May 2013

Speech intelligibility models consist of a preprocessing part that transforms the stimuli into some internal (auditory) representation, and a decision metric that quantifies effects of transmission channel, speech interferers, and auditory processing on the speech intelligibility. Here, two recent speech intelligibility models, the spectro-temporal modulation index [STMI; Elhilali et al. (2003)] and the speech-based envelope power spectrum model [sEPSM; Jo/rgensen and Dau (2011)] were evaluated in conditions of noisy speech subjected to reverberation, and to nonlinear distortions through either a phase jitter process or noise reduction via spectral subtraction. The contributions of the individual preprocessing stages in the models and the role of the decision metrics were analyzed in the different experimental conditions. It is demonstrated that an explicit across-frequency envelope processing stage, as assumed in the STMI, together with the metric based on the envelope power signal-to-noise ratio, as assumed in the sEPSM, are required to account for all three conditions. However, a simple weighting of the across-frequency variance of the modulation power at the output of the (purely temporal) modulation filterbank is assumed to be sufficient to describe the data, i.e., a joint two-dimensional modulation filterbank might not be required.
Comprehending speech at artificially enhanced rates
Authors: da Silva Lucia , Barbosa Adriano V. , Vatikiotis-Bateson Eric
Published: May 2013

This study is part of a larger study comparing the production, perception, and long-term comprehension of natural fast speech and artificially sped-up speech. In the 1950’s, Fairbanks and colleagues made the interesting claim that artificially compressing speech to half its duration (twice the rate) and listening to it twice is comprehended better than listening to the original natural speed utterance once. Since this finding has been disputed [T. Sticht, J. Expr. Ed. 37, 60–62 (1969)], we focus here on providing baseline results for perception of naturally produced speech at conversational and fast rate and of speech sped up to twice its original speed. Specifically, we compare how well the different stimuli are perceived when presented once, twice in rapid succession, and twice with delays of hours and days between presentations. We evaluate perception for both audio-only and audiovisual stimuli.
Influence of cochlear implantation on sentence intelligibility and duration
Authors: Peskova Olga , Srinivasan Nirmal Kumar , Shin Sujin , Sundarrajan Madhu , Tobey Emily
Published: May 2013

Cochlear implants (CI) allow children with hearing loss (HL) to achieve speech perception and production outcomes that make their spoken speech understandable to normal hearing adult listeners. This capability is characterize by wide variability of scores. In order to understand the factors that contribute to the overall variability, we investigated the effects of duration of cochlear implantation on speech intelligibility and sentence duration over time. Participants were 105 children implanted between the ages of 2 and 4 and tested at 2 time points there they were 8 and 16 years old. Participants repeated McGarr sentences, which vary in length from 3 to 5 to 7 syllables. Recording were analyze using acoustic software to designate the beginning and end of each sentence in listeners who only heard one sentence from one child. Speech intelligibility scores were related statistically to the duration of each sentence. Durations of sentences that approximated that of normal hearing listeners were those with high intelligibility judgment. In addition, it appears that the children with the longest experience of CI use continue to improve their intelligibility. [Sponsored by NIH.]