bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of subglottal resonances on bifurcations and register changes in laboratory models of phonation
Authors: Berry David , Neubauer Juergen , Zhang Zhaoyan
Published: October 2014

Many laboratory studies of phonation have failed to fully specify the subglottal system employed during research. Many of these same studies have reported a variety of nonlinear phenomena, such as bifurcations and vocal register changes. While such phenomena are often presumed to result from changes in the biomechanical properties of the larynx, such phenomena may also be a manifestation of coupling between the voice source and the subglottal tract. Using laboratory models of phonation, a variety of examples will be given of nonlinear phenomena induced by both laryngeal and subglottal mechanisms. Moreover, using tracheal tube lengths commonly reported in the literature, it will be shown that most of the nonlinear phenomena commonly reported in voice production may be replicated solely on the acoustical resonances of the subglottal system. Finally, recommendations will be given regarding the experimental design of laboratory experiments which may allow laryngeally induced bifurcations to be distinguished from subglottally induced bifurcations.
Subglottal ambulatory monitoring of vocal function to improve voice disorder assessment
Authors: Hillman Robert E. , Mehta Daryush , Van Stan Jarrad H. , Zanartu Matias , Ghassemi Marzyeh , Guttag John V.
Published: October 2014

Many common voice disorders are chronic or recurring conditions that are likely to result from inefficient and/or abusive patterns of vocal behavior, referred to as vocal hyperfunction. The clinical management of hyperfunctional disorders would be greatly enhanced by the ability to monitor and quantify detrimental vocal behaviors during an individual’s activities of daily life. This presentation will provide an update about ongoing work that is using a miniature accelerometer on the subglottal neck surface to collect a large set of ambulatory data on patients with hyperfunctional voice disorders (before and after treatment) and matched control subjects. Three types of analysis approaches are being employed in an effort to identify the best set of measures for differentiating among hyperfunctional and normal patterns of vocal behavior: (1) previously developed ambulatory measures of vocal function that include vocal dosages; (2) measures based on estimates of glottal airflow that are extracted from the accelerometer signal using a vocal system model, and (3) classification based on machine learning approaches that have been used successfully in analyzing long-term recordings of other physiologic signals (e.g., electrocardiograms).
Relationship between lung volumes and subglottal resonances
Authors: Duvanenko Natalie E. , Lulich Steven M.
Published: October 2014

Subglottal resonances are dependent the anatomical structure of the lungs, but efforts to detect changes in subglottal resonances throughout an utterance have failed to show any effect of lung volume. In this study, we present the results of an experiment investigating the relationship between lung volumes and subglottal resonances. The pulmonary subdivisions for several speakers were established using a whole-body plethysmograph. Subsequently, lung volume and subglottal resonances were recorded simultaneously using a spirometer and an accelerometer while the speakers produced long sustained vowels.
Labels facilitate the learning of competing abstract perceptual mappings
Authors: Heald Shannon L. , Bartram Nina , Colson Brendan , Nusbaum Howard C.
Published: October 2014

Listeners are able to quickly adapt to synthetic speech, even though it contains misleading and degraded acoustic information. Previous research has shown that testing and training on a given synthesizer using only novel words leads listeners to form abstract or generalized knowledge for how that particular synthesizer maps different acoustic patterns onto their pre-existing phonological categories. Prior to consolidation, this knowledge has been shown to be susceptible to interference. Given that labels have been argued to stabilize abstract ideas in working memory and to help learners form category representations that are robust against interference, we examined how learning for a given synthesizer is affected by labeled or unlabeled immediate training on an additional synthesizer, which uses a different acoustic to phonetic mapping. We demonstrated that the learning of an additional synthesizer interferes with the retention of a previously learned synthesizer but that this is ameliorated if the additional synthesizer is labeled. Our findings indicate that labeling may be important in facilitating daytime learning for competing abstract perceptual mappings prior to consolidation and suggests that speech perception may be best understood through the lens of perceptual categorization.
When more is not better: Variable input in the formation of robust word representations
Authors: Davis Andrea K. , Gerken LouAnn
Published: October 2014

A number of studies with infants and with young children suggest that hearing words produced by multiple talkers helps learners to develop more robust word representations (Richtsmeier et al., 2009; Rost & McMurray, 2009, 2010). Native adult learners, however, do not seem to derive the same benefit from multiple talkers. A word-learning study with native adults was conducted, and a second study with second language learners will have been completed by this fall. Native-speaking participants learned four new minimal English-like minimal pair words either from a single talker or from multiple talkers. They were then tested with (a) a perceptual task, in which they saw the two pictures corresponding to a minimal pair, heard one of the pair, and had to choose the picture corresponding to the word they heard; (b) a speeded production task, in which they had to repeat the words they had just learned as quickly as possible. Unlike infants, the two groups did not differ significantly in perceptual accuracy. However, the single talker group had significantly higher variance in the speeded production task. It is hypothesized that this greater variance is due to individual differences in learning strategies, which are masked when learning from multiple talkers.
Perceptual categorization of /r/ for children with residual sound errors
Authors: Hamilton Sarah M. , Boyce Suzanne , Mullins Lindsay
Published: October 2014

Many studies have found that children with resistant speech sound errors (RSSD) show (1) atypical category boundaries, and (2) difficulty identifying whether their own productions are correct or misarticulated. Historically, perceptual category discrimination tests use synthesized speech representing incremental change along an acoustic continuum, while tests of a child’s self-perception are confined to categorical correct vs. error choices. Thus, it has not been possible to explore the boundaries of RSSD children’s categorical self-perception in any detail or to customize perceptual training for therapeutic purposes. Following an observation of Hagiwara (1995), who noted that typical speakers show F3 values for /r/ between 80% and 60% of their average vowel F3, Hamilton et al (2014) found that this threshold largely replicates adult listener judgments, such that productions above and below the 80% threshold sounded consistently “incorrect” or “correct,” but that productions closest to the 80% threshold were given more ambiguous judgments. In this study, we apply this notion of an F3 threshold to investigate whether children with RSD respond like adult listeners when presented with natural-speech stimuli along a continuum of correct and incorrect /r/. Preliminary results indicate that children with RSD do not make adult-like decisions when categorizing /r/ productions.
A child-specific compensatory mechanism in the acquisition of English /s/
Authors: Bang Hye-Young , Clayards Meghan , Goad Heather
Published: October 2014

This study examines corpus data involving word-initial [sV] productions from 79 children aged 2–5 (Edwards & Beckman 2008) in comparison with a corpus of word-initial [sV] syllables produced by 13 adults. We quantified target-like /s/ production using spectral moment analysis on the frication portion (high center of gravity, low SD, and low skewness). In adults, we found that higher vowels (low F1 after normalization) were associated with more target-like /s/ productions, likely reflecting a tighter constriction. In children, older subjects produced more target-like outputs overall. However, unlike adults, children’s outputs before low vowels were more target-like, regardless of age. This is unexpected given the articulatory challenges of producing /s/ in low vowel contexts. Further investigation found that high F1 (low vowels) was associated with louder /s/ (relative to V) and more encroachment of sibilant noise on the following vowel (high harmonics-to-noise ratio). This finding suggests that young children may be increasing airflow during /s/ production to compensate for a less tight constriction when the jaw must lower for the following vowel. Thus, children may adopt a more accessible mechanism, different from adults, to compensate for their immature lingual gestures, possibly in an attempt to maximize phonological contrasts in word-initial position.
Effects of vowel position and place of articulation on voice onset time in children: Longitudinal data
Authors: Hitchcock Elaine R. , Koenig Laura L.
Published: October 2014

Voice onset time (VOT) has been found to vary according to phonetic context, but past studies report varying magnitudes of effect, and no past work has evaluated the degree to which such effects are consistent over time for a single speaker. This study explores the relationships between vowel position, consonant place of articulation [POA], and voice onset time (VOT) in children, comparing the results to past adult work. VOT in CV/CVC words was measured in nine children ages 5;3–7;6 every two-four weeks for 10 months, for a total of 18 sessions yielding approximately 18,000 tokens for analysis. Bilabial and velar cognate pairs targeted a front-back vowel difference (/i/-/u/, /e/-/o/), while alveolar cognate pairs targeted a mid high-low vowel difference (/o/-/ɑ/). VOT variability over time was also evaluated. Preliminary results suggest that POA yields a robust pattern of bilabial < alveolar < velar, but vowel effects are less clear. Vowel height shows the most obvious effect with consistently longer VOT values observed for mid high vowels. Front-back vowel comparisons yielded no obvious differences. On the whole, contextual variations based on POA and vowel context do not show clear correlations with overall VOT variation.
Longitudinal data on the production of content versus function words in children's spontaneous speech
Authors: Kallay Jeffrey , Redford Melissa A.
Published: October 2014

Allen and Hawkins (1978; 1980) were among the first to note rhythmic differences in the speech of children and adults. Sirsa and Redford (2011) found that rhythmic differences between younger and older children’s speech was best accounted for by age-related differences in function word production. In other on-going work (Redford, Kallay & Dilley) we found an effect of age on the perceived prominence of function words in children’s speech, but no effect on content words. The current longitudinal study investigated the effect of word class (content versus function words) on the development of reduction in terms of syllable duration and pitch range (a correlate of accenting). Spontaneous speech was elicited for 3 years from 36 children aged 5; 2–6; 11 at time of first recording. There were effects of word class (content > function) and of time on median duration, but no interaction between these factors. The median duration decreased 13% in function words from the 1st to 3rd year; a similar decrease (15%) was found for content words. Pitch range only varied systematically with word class. Other spectral measures are being collected to further investigate the development of reduction in children's speech. [Work supported by NICHD.]
Genetic variation in catechol-O-methyl transferase activity impacts speech category learning
Authors: Yi Han-Gyol , Maddox W. T. , Knopik Valerie S. , McGeary John E. , Chandrasekaran Bharath
Published: October 2014

Learning non-native speech categories is a challenging task. Little is known about the neurobiology underlying speech category learning. In vision, two dopaminergic neurobiological learning systems have been identified: a rule-based reflective learning system mediated by the prefrontal cortex, wherein processing is under deliberative control, and an implicit reflexive learning system mediated by the striatum. During speech learning, successful learners initially use simple reflective rules but eventually transition to a multidimensional reflexive strategy during later learning. We use a neurocognitive-genetic approach to identify intermediate phenotypes that modulate reflective brain function and examine their effects on speech learning. We focus on the COMT Val158Met polymorphism, which is linked to altered prefrontal function. The COMT-Val variant catabolizes dopamine more rapidly and is linked to poorer performance on prefrontally-mediated tasks. Adults (Met-Met: = 40; Met-Val= 75; Val-Val = 54) learned to categorize non-native Mandarin tones over five blocks of feedback-based training. Learning rates were the highest for the Met-Met genotype; the Val-Val genotype was associated with poorer overall learning. Poorer learning indicates increased perseveration of reflective unidimensional rule use, thereby preventing the transition to the reflexive system. We conclude that genetic variation is an important source of individual differences in complex phenotypes such as speech learning.
Waveform processing using entropy instead of energy: A quantitative comparison based on the heat equation
Authors: Hughes Michael , McCarthy John , Marsh Jon , Wickline Samuel
Published: October 2014

Virtually all modern imaging devices function by collecting electromagnetic or acoustic backscattered waves and using the energy carried by these waves to determine pixel values that build up what is basically an “energy” picture. However, waves also carry “information” that also may be used to compute the pixel values in an image. We have employed several measures of information, most sensitive being the “joint entropy” of the backscattered wave and a reference signal. Numerous published studies have demonstrated the advantages of “information imaging,” over conventional methods for materials characterization and medical imaging. A typical study is comprised of repeated acquisition of backscattered waves from a specimen that is changing slowing with acquisition time or location. The sensitivity of repeated experimental observations of such a slowly changing quantity may be defined as the mean variation (i.e., observed change) divided by mean variance (i.e., observed noise). Assuming the noise is Gaussian and using Wiener integration to compute the required mean values and variances, solutions to the Heat equation may be used to express the sensitivity for joint entropy and signal energy measurements. There always exists a reference such that joint entropy has larger variation and smaller variance than the corresponding quantities for signal energy, matching observations of several studies. A general prescription for finding an “optimal” reference for the joint entropy emerges, which has been validated in several studies.
The classification of underwater acoustic target signals based on wave structure and support vector machine
Authors: Meng Qingxin , Yang Shie , Piao Shengchun
Published: October 2014

The sound of propeller is a remarkable feature of ship-radiated noise, the loudness and timbre of which are usually applied to identify types of ships. Since the information of loudness and timbre is indicated in the wave structure of time series, the feature of wave structure can be extracted to classify types of various underwater acoustic targets. In this paper, the method of feature vector extraction of underwater acoustic signals based on wave structure is studied. The nine-dimension features are constructed via signal statistical characteristics of zero-crossing wavelength, peek-to-peek amplitude, zero-crossing wavelength difference, and wave train areas. And then, the support vector machine (SVM) is applied as a classifier for two kinds of underwater acoustic target signals. The kernel function is set radial basis function (RBF). By properly setting the penalty factor and parameter of RBF, the recognition rate reaches over 89.5%, respectively. The sea-test data shows the validity of target recognition ability of the method above.
Competitive algorithm blending for enhanced source separation of convolutive speech mixtures
Authors: Gilbert Keith , Payton Karen , Goldhor Richard , MacAuslan Joel
Published: October 2014

This work investigates an adaptive filter network in which multiple blind source separation methods are run in parallel, and the individual outputs are combined to produce estimates of acoustic sources. Each individual algorithm makes assumptions about the environment (dimensions of enclosure, reflections, reverberation, etc.) and the sources (speech, interfering noise, position, etc.), which constitutes an individual hypothesis about the observed microphone outputs. The goal of this competitive algorithm blending (CAB) approach is to achieve the performance of the “true” method, i.e., the method that has full knowledge of the environment's and the sources’ characteristics a priori, without any prior information. Results are given for time-invariant, critically- and over- determined, convolutive mixtures of speech and interfering noise sources, and the performance of the CAB method is compared with the “true” method in both the transient adaptation phase and in steady state.
Structural infrasound signals in an urban environment
Authors: McComas Sarah , Diaz-Alvarez Henry , Pace Mike , McKenna Mihan
Published: October 2014

Historically, infrasound arrays have been deployed in rural environments where anthropological noise sources are limited. As interest in monitoring sources at local distances grows in the infrasound community, it will be vital to understand how to monitor infrasound sources in an urban environment. Arrays deployed in urban centers have to overcome the decreased signal to noise ratio and reduced amount of real estate available to deploy an array. To advance the understanding of monitoring infrasound sources in urban environments, we deployed local and regional infrasound arrays on building rooftops of the campus of Southern Methodist University (SMU) and collected data for one seasonal cycle. The data was evaluated for structural source signals (continuous-wave packets) and when a signal was identified the back azimuth to the source was determined through frequency wavenumber analysis. This information was used to identify hypothesized structural sources; these sources were verified through direct measurement, structural numerical modeling and/or full waveform propagation modeling. Permission to publish was granted by Director, Geotechnical & Structures Laboratory.
Design of a speaker array system based on adaptive time reversal method
Authors: Too Gee-Pinn J. , Chen Yi-Tong , Lin Shen-Jer
Published: October 2014

A system for focusing sound around desired locations by using a speaker array of controlled sources is proposed. To increase acoustic signal in certain locations where the user is within but to reduce it in the other certain locations by controlling source signals is the main objective of this study. Based on adaptive time reversal theory, input weighting coefficients for speakers are evaluated for the speaker sources. Experiments and simulations with a speaker array of controlled sources are established in order to observe the distribution of sound field under different boundary and control conditions. The results indicate that based on the current algorithm, the difference of sound pressure level between bright point and dark point can be as high as 12 dB with an eight speakers array system.
Choice of acoustics signals family in multi-users environment
Authors: Ollivier Benjamin , Maussang Frédéric , Garello René
Published: October 2014

Our application concerns a system immersed in an underwater acoustical context, with Nt transmitters and Nr slowly moving receivers. The objective is that all receivers detect the transmitted signals, in order to estimate the time of arrival (TOA) and then to facilitate the localization when several TOA (more than 3) are present. We have to choose a method to generate a number Ns of broad-band signals to use the Code Division Multiple Access (CDMA) modulation, specially adapted to our problem. This work is devoted to selecting Nt signals among the Ns available. The aim is to choose the most distinctly detectable ones. First, in a no Doppler context, the criterion of signals selection is based on a ratio between maximum of auto-correlation and cross-correlation. Second, in the presence of Doppler, we rely on Ambiguity Function which allows representing the correlation function to several frequency Doppler shifts. The choice of Nt signals is then based on ratio between maximum of auto-ambiguity and cross-ambiguity. In this paper we will highlight the relevance of the criteria (correlation, ambiguity function) in the choice of the most appropriate signals in function of the multi-users context.
Persistence of sharp acoustic backscatter transitions observed in repeat 400 kHz multibeam echosounder surveys offshore Panama City, Florida, over 1 and 24 months
Authors: de Moustier Christian , Kraft Barbara J.
Published: October 2014

The Target and Reverberation Experiment 2013 (TREX13), conducted offshore Panama City, FL, from April to June 2013, sought to determine which environmental parameters contribute the most to acoustic reverberation and control sonar performance prediction modeling for acoustic frequencies between 1 kHz and 10 kHz. In that context, a multibeam echosounder operated at 400 kHz was used to map the seafloor relief and its high-frequency acoustic backscatter characteristics along the acoustic propagation path of the reverberation experiment. Repeat surveys were conducted a month apart, before and after the main reverberation experiment. In addition, repeat surveys were conducted at 200 kHz in April 2014. Similar mapping work was also conducted in April 2011 during a pilot experiment (GulfEx11) near the site chosen for TREX13. Both experiments revealed a persistent occurrence of sharp transitions from high to low acoustic backscatter at the bottom of swales. Hypotheses are presented for observable differences in bathymetry and acoustic backscatter in the overlap region between the GulfEx11 survey and the TREX13 surveys conducted 2 y apart. [Work supported by ONR 322 OA.]
Roughness measurement by laser profiler and acoustic scattering strength of a sandy bottom
Authors: Chotiros Nicholas P. , Isakson Marcia J. , Siliceo Oscar E. , Abkowitz Paul M.
Published: October 2014

The roughness of a sandy seabed off Panama City, FL, was measured with a laser profiler. This was the site of the target and reverberation experiment of 2013 (TREX13) in which propagation loss and reverberation strength were measured. The area may be characterized as having small scale roughness due to bioturbation overlaying larger sand ripples due to current activity. The area was largely composed of sand with shell hash crossed by ribbons of softer sediment at regular intervals. The roughness measurements were concentrated in the areas where the ribbons intersected the designated sound propagation track. Laser lines projected on the sand were imaged by a high-definition video recorder. The video images were processed to yield bottom profiles in three dimensions. Finally, the roughness data are used to estimate acoustic bottom scattering strength. [Work supported by the Office of Naval Research, Ocean Acoustics Program.]
Seafloor sub-bottom Imaging along the TREX reverberation track
Authors: Lopes Joseph L. , Arrieta Rodolf , Paustian Iris , Pineda Nick , Williams Kevin
Published: October 2014

The Buried Object Scanning Sonar (BOSS) integrated into a Bluefin12 autonomous underwater vehicle was used to collect seafloor sub-bottom data along the TREX reverberation track. BOSS is a downward looking sonar and employs an omni-directional source to transmit a 3 to 20 kHz linear frequency modulated (LFM) pulse. Backscattered signals are received by two 20-channel linear hydrophone arrays. The BOSS survey was carried out to support long-range reverberation measurements at 3 kHz. The data were beamformed in three dimensions and processed into 10cm x 10cm x 10cm voxel maps of backscattering to a depth of 1 m. Comparison of the BOSS imagery with 400 kHz multibeam sonar imagery of the seafloor allows muddy regions to be identified and shows differences rationalized by the differences in sediment penetration of the two frequency ranges utilized. Processed BOSS data are consistent with observations from diver cores and the reverberation data collected by stationary arrays deployed on the seafloor. Specifically, stronger and deeper backscattering from muddy regions is observed (relative to near-by sandy regions). This correlates well with the large amounts of detritus (e.g., shell fragments) and complicated vertical layering within cores, and the enhanced reverberation, from those regions. [Work supported by ONR.]
Seabed characterisation using a low cost digital thin line array: Results from the Target and Reverberation Experiments 2013
Authors: Chandrika Unnikrishnan K. , Pallayil Venugopalan , Chotiros Nicholas , Isakson Marcia
Published: October 2014

During TREX-13 experiments in the Gulf of Mexico in May 2013, the use of a low cost digital thin line array (DTLA) developed at the Acoustic Research Lab, National University of Singapore was explored towards sea-bottom characterisation. The array, developed for use from AUV platforms, was hosted on a Sea-eye ROV from UT Austin and towed using R/V Smith, as no AUV platform was available during the course of the above experiment. The ROV was also hosting a wide-band acoustic source sending out chirp waveforms in the frequency range of 3 to 15 kHz. It has been observed that despite the complexity of set-up used, the array dynamics could be maintained well during the tow test and also the data collected were useful in estimating the bottom type from reflection coefficient measurements and comparing with the models available. Our analysis by matched filtering the received data and estimating the bottom reflection coefficient showed that the bottom type at the experimental site was sandy-silt, which fairly compared with observations on the same by other means. Details of experiments performed and the results from the data analyzed would be presented during the meeting. Some suggestions for improvement for future experiments will be discussed.
Wide-angle reflection measurements (TREX13): Evidence of strong seabed lateral heterogeneity at two scales
Authors: Holland Charles W. , Smith Chad , Hines Paul , Dettmer Jan , Dosso Stan , Pinson Samuel
Published: October 2014

Broadband wide-angle reflection data possess high information content, yielding both depth and frequency dependence of sediment wave velocities, attenuations, and density. Measurements at two locations off Panama City, FL (TREX13), however, presented a surprise: over the measurement aperture (a few tens of meters) the sediment was strongly laterally variable. This prevented the usual analysis in terms of depth dependent geoacoustic properties. Only rough estimates could be made. On the other hand, the data provide clear evidence of lateral heterogeneity at O(100-101) m scale. The two sites were separated by ~6 km, one on a ridge (lateral dimension 102 m) and one in a swale of comparable dimension; the respective sound speeds are roughly 1680 m/s and 1585 m/s. The lateral variability, especially at the 1–10 m scale is expected to impact both propagation and reverberation. Characteristics of the reflection data and its attendant “surprise” suggest the possibility of objectively separating the intermingled angle and range dependence; this would open the door to detailed geoacoustic estimation in areas of strong lateral variability. [Research supported by ONR Ocean Acoustics.]
Tapping into the theatre of the mind; creating the eerie scene through sound
Authors: Whiting Jonathon
Published: October 2014

Jaws. Psycho. Halloween. Halo. Movies and video games depend on music and acoustics to evoke certain emotional states in the audience or game player. But what is the recipe for creating a haunting scene? A creaky door, a scream, a minor chord on a piano. How and why are certain emotions pulled out of a listener in response to sound? From sound environments to mental expectations, the media industry uses a variety of techniques to elicit responses from an audience. This presentation will discuss and present examples of the principles behind the sound of fright.
Disquiet: Epistemological bogeymen and other exploits in audition
Authors: White Ean
Published: October 2014

Beginning with an interest in “physiological musics,” Ean White’s sound art exploits interstices in our sensory apparatus with unnerving results. He will recount a series of audio experiments with effects ranging from involuntary muscle contractions to the creation of sounds eerily unique to each listener. The presentation will include discussion of his techniques and how they inform his artistic practice.
Documenting and identifying things that go bump in the night
Authors: Reuter Eric L.
Published: October 2014

Acoustical consultants are occasionally asked to help diagnose mysterious noises in buildings, and it can be difficult to be present and ready to make measurements when such noises occur. This paper will presents some of the tools and methods the author uses for recording and analyzing these events. These include the use of tablet-based measurement devices and high-speed playback of long-term recordings.
The mysterious case of the singing toilets and other nerve wracking tales of unwanted sound
Authors: Woolworth David S.
Published: October 2014

Lightweight construction nightmares, devilish designs that never see acoustic review, improper purposing of spaces, and other stories involving the relentless torture of building occupants. Will they survive?
Sound effects with AUditory syntaX—A high-level scripting language for sound processing
Authors: Kwon Bomjun J.
Published: October 2014

AUditory syntaX (AUX) is a high-level scripting programming language specifically crafted for the generation and processing of auditory signals (Kwon, 2012; Behav Rev 44, 361–373). AUX does not require knowledge or prior experience in computer programming. Rather, AUX provides an intuitive and descriptive environment where users focus on perceptual components of the sound, without tedious tasks unrelated to the perception such as memory management or array handling often required in other computer languages such as C + + or MATLAB that are popularly used in auditory science. This presentation provides a demonstration of AUX for the generation and processing of various sound effects, particularly “fun” or “spooky” sounds. Processing methods for sound effects widely used in arts, films and other media, such as reverberation, echoes, modulation, pitch shift, and flanger/phaser, will be reviewed and coding in AUX to generate those effects and the generated sounds will be demonstrated.
Eerie voices: Odd combinations, extremes, and irregularities
Authors: Story Brad H.
Published: October 2014

The human voice can project an eerie quality when certain characteristics are present in a particular context. Some types of eerie voices may be derived from physiological scaling of the speech production system that is either humanly impossible or nearly so. By combining previous work on adult speech, and current research on speech development, the purpose of this study was to simulate vocalizations and speech based on unusual configurations of the vocal tract and vocal folds, and by imposing irregularities on movement and vibration. The resulting sound contains qualities that are human-like, but not typical, and hence may give the perceptual impression of eeriness. [Supported in part by NIH R01-DC011275.]
Are you hearing voices in the high frequencies of human speech and voice?
Authors: Monson Brian B.
Published: October 2014

The human voice produces acoustic energy at frequencies above 6 kHz. Energy in this high-frequency region has long been known to affect perception of speech and voice quality, but also provides non-qualitative information about a speech signal. This presentation will demonstrate how much useful information can be gleaned from the high frequencies with a report on studies where listeners were presented with only high-frequency energy extracted from speech and singing. Come to test your own abilities and decide if you can hear strange voices or just chirps and whistles in the high frequencies of human speech and voice.
Measuring the impact of room acoustics on emotional responses to music using functional neuroimaging: A pilot study
Authors: Lawless Martin S. , Vigeant Michelle C.
Published: October 2014

Past cognitive neuroscience studies have established links between music and an individual’s emotional response. Specifically, music can induce activations in brain regions most commonly associated with reward and pleasure (Blood/Zatorre PNAS 2001). To further develop concert hall design criteria, functional magnetic resonance imaging (fMRI) techniques can be used to investigate the emotional preferences of room acoustics stimuli. Auralizations were created under various settings ranging from anechoic to extremely reverberant. These stimuli were presented to five participants in an MRI machine, and the subjects were prompted to rate the stimuli in terms of preference. Noise stimuli that matched the acoustic stimuli temporally and spectrally were also presented to the participants for the analysis of main contrasts of interest. In addition, the participants were first tested in a mock scanner to acclimatize the subjects to the environment and later validate the results of the study. Voxel-wise region of interest analysis was used to locate the emotion and reward epicenters of the brain that were activated when the subjects enjoyed a hall’s acoustics. The activation levels of these regions, which are associated with positive-valence emotions, were examined to determine if the activations correlate with preference ratings.
Development of speech perception under adverse listening conditions
Authors: Bent Tessa
Published: October 2014

Speech communication success is dependent on interactions among the talker, listener, and listening environment. One such important interaction is between the listener’s age and the noise and reverberation in the environment. Previous work has demonstrated that children have greater difficulty than adults in noisy and highly reverberant environments, such as those frequently found in classrooms. I will review research that considers how a talker’s production patterns also contribute to speech comprehension, focusing on nonnative talkers. Studies from my lab have demonstrated that children have more difficulty than adults perceiving speech that deviates from native language norms, even in quiet listening conditions in which adults are highly accurate. When a nonnative talker’s voice was combined with noise, children’s word recognition was particularly poor. Therefore, similar to the developmental trajectory for speech perception in noise or reverberation, the ability to accurately perceive speech produced by nonnative talkers continues to develop well into childhood. Metrics to quantify speech intelligibility in specific rooms must consider both listener characteristics, talker characteristics, and their interaction. Future research should investigate how children’s speech comprehension is influenced by the interaction between specific types of background noise and reverberation and talker production characteristics. [Work supported by NIH-R21DC010027.]
Speech comprehension in realistic classrooms: Effects of room acoustics and foreign accent
Authors: Peng Zhao , Boyd Brenna N. , Hanna Kristin E. , Wang Lily M.
Published: October 2014

The current classroom acoustics standard (ANSI S12.60) recommends that core learning spaces shall not exceed reverberation time (RT) of 0.6 second and background noise level (BNL) of 35 dBA, based on speech intelligibility performance mainly by the native English-speaking population. This paper presents two studies on the effects of RT and BNL on more realistic classroom learning experiences. How do native and non-native English-speaking listeners perform on speech comprehension tasks under adverse acoustic conditions, if the English speech is produced by talkers whose native language is English (Study 1) versus Mandarin Chinese (Study 2)? Speech comprehension materials were played back in a listening chamber to individual listeners: native and non-native English-speaking in Study 1; native English, native Mandarin Chinese, and other non-native English-speaking in Study 2. Each listener was screened for baseline English proficiency for use as a covariate in the statistical analysis. Participants completed dual tasks simultaneously (speech comprehension and adaptive dot-tracing) under 15 different acoustic conditions, comprised of three BNL conditions (RC-30, 40, and 50) and five RT scenarios (0.4–1.2 s). Results do show distinct differences between the listening groups. [Work supported by a UNL Durham School Seed Grant and the Paul S. Veneklasen Research Foundation.]
Quantifying a measure and exploring the effect of varying reflection densities from realistic room impulse responses
Authors: Hong Hyun , Wang Lily M.
Published: October 2014

Perceptual studies using objective acoustic metrics calculated from room impulse responses, such as reverberation time and clarity index, are common. Less work has been conducted looking explicitly at the reflection density, or the number of reflections per second. The reflection density, though, may well have its own perceptual influence when reverberation time and source-receiver distances are controlled, particularly in relation to room size perception. This paper presents first an investigation into quantifying the reflection density from realistic room impulse responses that may be measured or simulated. The resolution of the sampling frequency, time window applied, and cut-off level for including a reflection in the count are considered. The quantification method is subsequently applied to select a range of realistic RIRs for use in a perceptual study on determining the maximum audible reflection density by humans, using both speech and clapping signals. Results from this study are compared to those from similar previous work by the authors which used artificially simulated impulse responses with constant reflection densities over time.
A generalized random encounter model for estimating animal density with remote sensor data
Authors: Moorcroft Elizabeth , Lucas Tim C. D. , Freeman Robin , Rowcliffe Marcus J. , Jones Kate E.
Published: October 2014

Acoustic detectors are commonly being used to monitor wildlife. Current estimators of abundance or density require recognition of individuals or the distance of the animal from the sensor, which is often difficult. The random encounter model (REM) has been successfully applied to count data without these requirements. However, count data from acoustic detectors do not fit the assumptions of the REM due to the directionality of animal signals. We developed a generalized REM (gREM), to estimate animal density from count data, derived for different combinations of sensor detection widths and animal signal widths. We tested the accuracy and precision of this model using simulations for different combinations of sensor detection and animal signal widths, number of captures, and animal movement models. The gREM produces accurate estimates of absolute animal density. However, larger sensor detection and animal signal widths, and larger number of captures give more precise estimates. Different animal movement models had no effect on the gREM. We conclude that the gREM provides an effective method to estimate animal densities in both marine and terrestrial environments. As acoustic detectors become more ubiquitous, the gREM will be increasingly useful for monitoring animal populations across broad spatial, temporal, and taxonomic scales.
Using sound propagation modeling to estimate the number of calling fish in an aggregation from single-hydrophone sound recordings
Authors: Sprague Mark W. , Luczkovich Joseph J.
Published: October 2014

Many fishes make sounds during spawning events that can be used to estimate abundance. Spawning stock size is a measure of fish population size that is used by fishery biologists to manage harvests levels. It is desirable that such an estimate be assessed easily and remotely using passive acoustics. Passive acoustics techniques (hydrophones) can be used to identify sound-producing species, but it is difficult to count individual sound sources in the sea, where it is dark, background noise levels can be high, but species can be identified by their sounds. We have developed a method that can estimate the density of calling fish in an aggregation from single-hydrophone recordings. Our method requires a sound propagation model for the area in which the aggregation is located. We generate a library of modeled sounds of virtual Monte-Carlo generated distributions of fish to determine the range of fish population densities that match the characteristics of single-hydrophone sound recording. Such a model could be used from a fixed station (e.g., an observatory) to estimate the population size of the sound producers. In this presentation, we will present some calculations made using this method and will examine the benefits and limitations of the technique.
Spatial variation of the underwater soundscape over coral reefs in the Northwestern Hawaiian Islands
Authors: Freeman Simon E. , Freeman Lauren A. , Lammers Marc O. , Buckingham Michael J.
Published: October 2014

Coral reefs create a complex acoustic environment, dominated by sounds produced by benthic creatures such as crustaceans and echinoderms. While there is growing interest in the use of ambient underwater biological sound as a gauge of ecological state, extracting meaningful information from recordings is a challenging task. Single hydrophone (omnidirectional) recorders can provide summary time and frequency information, but as the spatial distribution of reef creatures is heterogeneous, the properties of reef sound arriving at the receiver vary with position and arrival angle. Consequently, the locations and acoustic characteristics of individual sound producers remain unknown. An L-shaped hydrophone array, providing direction-and-range sensing capability, can be used to reveal the spatial variability of reef sounds. Comparisons can then be made between sound sources and other spatially referenced information such as photographic data. During the summer of 2012, such an array was deployed near four different benthic ecosystems in the Northwestern Hawaiian Islands, ranging from high-latitude coral reefs to communities dominated by algal turf. Using conventional and adaptive acoustic focusing (equivalent to curved-wavefront beamforming), time-varying maps of sound production from benthic organisms were created. Comparisons with the distribution of nearby sea floor features, and the makeup of benthic communities, will be discussed.
Density estimates of odontocetes in an active military base using passive acoustic monitoring
Authors: Roberts Bethany L. , Swaim Zach , Read Andrew J.
Published: October 2014

We deployed passive acoustic monitoring devices in Camp Lejeune, North Carolina, USA, to estimate density of odontocete populations. Four C-PODs (echolocation click detectors) were deployed in water depths ranging from 13 to 21 meters from 30 November 2012 to 13 November 2013. Two species of odontocetes are known to inhabit the survey area: bottlenose dolphins and Atlantic spotted dolphins. These methods incorporate (i) the rate at which the animals produce echolocation cues, (ii) the probability of detecting cues, and (iii) the false positive rate of detections. To determine the cue rate of bottlenose dolphins, we attached DTAGs to 14 bottlenose dolphins during 2012 and 2013 in Sarasota, Florida. To determine cue rate of spotted dolphins, we used six recordings of focal follows from 2001-2003 in an area adjacent to C-POD deployment locations. Echolocation playbacks to C-PODs were used to obtain false positive rate and detection radius of each C-POD. Furthermore, we obtained proportions of bottlenose and spotted dolphins in the survey area from concurrent line transect surveys. Preliminary results indicate that dolphins were detected on all four C-PODs during every month of the survey period. Future studies in areas where multiple species are present could potentially use methods described here.
Toward acoustically derived population estimates in marine conservation: An application of the spatially-explicit capture-recapture methodology for North Atlantic right whales
Authors: Cholewiak Danielle , Brady Steven , Corkeron Peter , Davis Genevieve , Van Parijs Sofie
Published: October 2014

Passive acoustics provide a flexible tool for developing understanding of the ecology and behavior of vocalizing marine animals. Yet despite a robust capacity for detecting species presence, our ability to estimate population abundance from acoustics still remains poor. Critically, abundance estimates are precisely what conservation practitioners and policymakers often require. In the current study, we explored the application of acoustic data in the spatially-explicit capture-recapture (SECR) methodology, to evaluate whether acoustics can be used to infer abundance in the endangered North Atlantic right whale. We sub-sampled a year-long acoustic dataset from archival recorders deployed in Massachusetts Bay. Multichannel data were reviewed for the presence of up-calls. A total of 1659 unique up-calls were detected. Estimates of up-call density ranged from zero to 608 (± 70 SE) up-calls/hour. Estimates of daily abundance, when corrected for average calling rate, ranged from 0—69 (± 21 SE) individuals per day. These results qualitatively compare well with patterns in right whale occurrence reported from aerial-based visual surveys. Since acoustic abundance calculations are affected by variation in calling behavior, estimates should be interpreted cautiously; however, these results indicate that passive acoustics has the potential to directly inform conservation and management strategies.