bluuebunny/crossref_metadata_2025 huggingface dataset:
Pitch discrimination as a function of the inter-stimulus interval: Evidence against a simple model of perceptual memory
Authors: Demany Laurent , Montandon Gaspard , Semal Catherine
Published: October 2013

A listener’s ability to compare two sounds separated by a silent time interval T is limited by a sum of ‘‘sensory noise’’ and ‘‘memory noise.’’ The present work was intended to test a model according to which these two components of internal noise are independent and, for a given sensory continuum, the memory noise depends only on T. In three experiments using brief sounds (<80 ms), pitch discrimination performances were measured in terms of d′ as a function of T (0.1–4 s) and a physical parameter affecting the amount of sensory noise (pitch salience). As T increased, d′ first increased rapidly and then declined more slowly. According to the tested model, the relative decline of d′ beyond the optimal value of T should have been slower when pitch salience was low (large amount of sensory noise) than when pitch salience was high (small amount of sensory noise). However, this prediction was disproved in each of the three experiments. It was also found, when a ‘‘roving’’ procedure was used, that the optimal value of T was markedly shorter for very brief tone bursts (6 sine cycles) than for longer tone bursts (30 sine cycles).
F0 discrimination interference: Effects of resolved tone complexes and noise on fundamental frequency discrimination of unresolved complex tones
Authors: Gockel Hedwig , Carlyon Robert P. , Plack Christopher J.
Published: October 2013

F0 discrimination of a 400-ms complex tone with only unresolved components (‘‘target’’) was investigated in the absence and presence of a synchronously gated resolved complex tone (‘‘interferer’’). The target and the interferer were bandpass filtered from 1375–15000 Hz and 125–625 Hz, respectively. In a 2I-2AFC task, listeners indicated the interval containing the target with the higher pitch. The nominal F0 of the target was 88 Hz; that of the interferer was constant across the two intervals and was either 88 Hz or increased by various amounts. Although the target and interferer were in well-separated frequency regions, performance (percent correct) dropped by about 16% when the interferer’s F0 was 88 Hz. The impairment was halved when the interferer’s F0 was 10% higher than that of the target, and almost eliminated when it was 30% higher. Increasing the level of a 1375-Hz low-pass-filtered noise, gated synchronously with the target and the interferer (F0 equaled 88 Hz), improved performance, further demonstrating that the deterioration produced by the resolved complex was not due to peripheral masking. The results are consistent with a form of across-frequency interference at the level of pitch perception. [Work supported by EPSRC Grant GR/R65794/01.]
Effects of real and illusory glides on pure-tone frequency discrimination
Authors: Lyzenga Johannes , Carlyon Robert P. , Moore Brian C. J.
Published: October 2013

Pure-tone frequency difference limens (DLs) were measured for 500-ms, 4-, and 6-kHz pure tones, where the interval between the initial and final constant-frequency portions of the tones in each 2IFC trial consisted of either a silent gap, a frequency glide, or a noise burst. The noise was inserted to create the illusion of the tone continuing through the gap. The interval between the two constant-frequency portions was 0, 10, 50, or 200 ms; a condition with a 500-ms frequency glide without constant-frequency portions was also used. To prevent subjects from using information from the end point of the glides, a frequency rove of approximately four ERBs was used in all conditions. It was found that DLs were lower for the glide than for the gap condition, supporting the conclusion that the auditory system contains a mechanism specific for the detection of dynamic frequency changes [A. Sek and B. C. J. Moore, J. Acoust. Soc. Am. 106, 351–359 (1999)]. For a number of subjects, the DLs were smaller for the noise condition than for the gap condition, suggesting that this mechanism may be able to operate on a stage of processing at which an illusory glide has been introduced.
Comparison of behavioral discrimination, MMN, and P300 to speech and nonspeech stimuli
Authors: Webster Joanna , Harkrider Ashley , Hedrick Mark
Published: October 2013

Our objective is to examine the relation between central auditory processes and discrimination of speech (consonant–vowel) and nonspeech (frequency glide) stimuli. Behavioral responses and auditory evoked potentials (MMN and P300) of ten adults were evaluated to synthetically generated consonant–vowel (CV) speech and nonspeech contrasts. The CVs were two within-category stimuli and the nonspeech stimuli were two frequency glides whose frequencies matched the formant transitions of the CV stimuli. It was found that listeners exhibited significantly better behavioral discrimination to the nonspeech versus speech stimuli in same/different and oddball behavioral paradigms. MMN responses were present in all subjects to both stimulus contrasts, and were not significantly different with regard to stimulus type. P300’s were present in nine of ten subjects to both stimulus contrasts. However, the CV speech contrasts produced P300’s with significantly smaller amplitudes and longer latencies than those to the nonspeech stimuli. These results suggest that the stimuli were processed differently when measured behaviorally and with the P300, but not when measuring the MMN. The enhanced discrimination of the frequency glide stimuli versus the CV stimuli of analogous acoustical content supports the idea that different levels of processing mediate the auditory perception of speech versus nonspeech stimuli.
Phase effects in forward masking for normally hearing and hearing-impaired subjects
Authors: Moore Brian C. J. , Stainsby Thomas , Terasewicz Esme
Published: October 2013

The forward masking produced by harmonic complex tones depends on the phases of the masker components; phases giving ‘‘peaky’’ waveforms on the basilar membrane result in less forward masking than phases giving less peaky waveforms. This difference has been attributed to the effects of peripheral compression and suppression, which depend on the active mechanism in the cochlea. Hence, no phase effect would be expected for subjects with moderate cochlear hearing loss. Growth-of-masking functions were measured for forward maskers containing the first 40 harmonics of a 100-Hz fundamental, with components added in cosine (C) or random (R) phase. The signal frequency was 1 or 2 kHz. For three normally hearing subjects, the R masker produced considerably more masking than the C masker, at high masker levels. Of four subjects with moderate cochlear hearing loss, one showed no effect of masker phase, but for the other three there was a significant effect for at least one signal frequency. It is suggested that peripheral compression and suppression play a role in the phase effect, but other factors, possibly depending on the operation of the efferent system, are involved. [Work supported by MRC (UK).]
Role of short-term memory in loudness comparisons
Authors: Ellermeier Wolfgang , Werner Birgit
Published: October 2013

In an earlier study of the auditory discrimination of time-varying noise bursts [Ellermeier and Schrödl, J. Acoust. Soc. Am. 108, 2596 (2000)], listeners were found to place greater weight on the beginning and end of the sounds than on the middle portion. To investigate whether this outcome is due to primacy and recency effects in short-term memory which tend to be sensitive to manipulations of the inter-stimulus interval (ISI), the ISI separating the two noise bursts in a 2IFC task was varied systematically. Six participants performed loudness comparisons on 1-s samples of white noise randomly changing in level every 100 ms. In different blocks of trials, the two noise bursts to be compared were either separated by a 500-ms or a 2-s ISI. COSS analysis [Berg, J. Acoust. Soc. Am. 86, 1743–1746 (1989)] of the overall loudness judgments revealed elevated weights for the beginning and end of the noises, as in the earlier study. These weighting patterns were largely unaffected by the manipulation of ISI, suggesting that the temporal weights found characterize loudness integration in general, and are not just due to idiosyncrasies of the timing used in the 2IFC procedure.
Chaotic properties and eigenfrequency distribution of Semi-Stadium 2-D Fields
Authors: Tohyama Mikio , Fujisaka Yoh-ichi , Yoshida Kazuaki
Published: October 2013

This paper describes the eigenfrequency distribution of semi-stadium 2-D fields whose geometrical figure is formed by rectangular and hyper-circular segments. The sound ray propagation in the fields exhibits chaotic properties when order n of the hyper-circular parts defined by xn+yn=rn decreases to 2. The chaotic behavior can be estimated according to the degree of freedom of the gamma distribution that represents the eigenfrequency spacing statistics and the correlation dimensions of the chaotic structure. The experimental and simulation results of the 2-D-membrane and plate vibration analysis show that the degree of freedom of the gamma distribution changes from 1 to 2 including nonintegers as the boundary of the 2-D space changes from rectangular (n: infinity, ‘‘regular field’’) to stadium (n: 2, ‘‘irregular field’’), which corresponds to the change in the correlation dimensions from 1 to 2 for the sound ray propagation in the field. The family of gamma distributions includes the Wigner distribution, which Lyon [J. Acoust. Soc. Am. 45, 545–565 (1969)] assumed for irregularly shaped boundaries as the case where the degree of freedom is 2.
Assessment of a spectral energy formulation based on driving point structural mobilities or impedances
Authors: Kim Seungbo , Singh Raj
Published: October 2013

To determine the contributions of parallel paths or interactions between structural components at any frequency, dynamic kinetic and potential energies are needed. However, an exact method to characterize an arbitrarily damped system in kinetic and potential energy forms is currently not available. One approximate characterization method examines time-averaged dynamic energies of subsystem(s) via the driving point transfer functions [J. Sound Vib. 217, 351–386 and 247, 683–702]. This concept, based on a real-valued energy formulation, is critically examined here. Linear time-invariant (LTI) system is assumed and harmonic excitation is applied to the system. Finite continuous (bar and beam) structures along with discrete system examples are utilized to illustrate concepts. Predictions show that the energy estimates deviate from the exact values, especially at higher frequencies and with higher damping. Further, the results from the impedance formulation differ from the ones from the mobility representation. The cause of discrepancies is explained by interpreting the transfer functions involved.
Experiments and interpretation of surface waves acoustically generated on spherically endcapped cylindrical shells
Authors: Ahyi A. Claude , Cao Hui , Raju P. K. , Überall H.
Published: October 2013

The impact of an acoustic pulse on a submerged elastic shell (which we shall assume evacuated) generates three types of circumferentially propagating surface waves: those that are analogous to plate waves of type A0(A1,A2,...) and S0(S1,S2,...), and a Scholte–Stoneley wave of type A that propagates in the surrounding fluid. A computer program devised by Hui Cao et al. renders visualizations of the generation and propagation of circumferential pulses on spherically endcapped shells, visualized by the re-radiation into the surrounding fluid of A, A0, and S0 waves in sequential pictures. These surface waves are generated experimentally by us in the laboratory from an ultrashort-pulse source, at axial incidence on a hemispherically endcapped glass tube. Sequential visualizations of the re-radiated pulses are obtained by using the Schardin–Cranz Schlieren method. These observations lead to an experimental measure of the group velocity dispersion curves of the surface waves.
Production and perception of clear speech
Authors: Bradlow Ann R.
Published: October 2013

When a talker believes that the listener is likely to have speech perception difficulties due to a hearing loss, background noise, or a different native language, she or he will typically adopt a clear speaking style. Previous research has established that, with a simple set of instructions to the talker, ‘‘clear speech’’ can be produced by most talkers under laboratory recording conditions. Furthermore, there is reliable evidence that adult listeners with either impaired or normal hearing typically find clear speech more intelligible than conversational speech. Since clear speech production involves listener-oriented articulatory adjustments, a careful examination of the acoustic-phonetic and perceptual consequences of the conversational-to-clear speech transformation can serve as an effective window into talker- and listener-related forces in speech communication. Furthermore, clear speech research has considerable potential for the development of speech enhancement techniques. After reviewing previous and current work on the acoustic properties of clear versus conversational speech, this talk will present recent data from a cross-linguistic study of vowel production in clear speech and a cross-population study of clear speech perception. Findings from these studies contribute to an evolving view of clear speech production and perception as reflecting both universal, auditory and language-specific, phonological contrast enhancement features.
Elderspeak
Authors: Kemper Susan
Published: October 2013

Elderspeak has been assumed to be an accommodation to the perceived communication needs of older adults as it involves a slow rate of speaking, simplified syntax, vocabulary restrictions, and exaggerated prosody. It also is judged to be patronizing and disrespectful in that its use presumes that the older adult is cognitively impaired. Using a controlled referential communication task, my colleagues and I have investigated elderspeak addressed by young adults to older adults. Our studies suggest that the speech register is composed of two sets of parameters. One set of parameters is linked to the perception that the older listener is cognitively impaired; these parameters affect how much information is conveyed and include semantic elaborations such as expansions and repetitions of previous map directions. The other set of parameters includes fluency, prosody, and grammar. The modifications to fluency and prosody do not appear to benefit older listeners. In these studies, the young adults’ use of elderspeak did improve the performance of the older listeners on the referential communication task. The use of elderspeak by the young partners appeared to trigger older adults’ perceptions of themselves as cognitively impaired, consistent with the ‘‘communicative predicament of aging’’ model of Ryan et al. (1986).
Predicting children’s hyperarticulate speech during human-computer error resolution
Authors: Oviatt Sharon , Coulston Rachel , Darves Courtney
Published: October 2013

When speaking to interactive systems, people sometimes hyperarticulate—or adopt a clarified form of speech that has been associated with increased recognition errors. The goal of the present study was to provide a comprehensive assessment of the type and magnitude of linguistic adaptations in children’s speech during human-computer error resolution, and to compare these adaptations with those typical of adult hyperarticulation. A study was conducted in which twenty-four 7- to- 10-year-old children interacted with a simulated conversational system, which permitted a comparison of their verbatim repetitions immediately before and after system recognition errors. Matched original-repeat utterance pairs then were analyzed for acoustic, prosodic, and phonological adaptations. Like adult speech, the primary hyperarticulate changes in children’s speech included durational phenomena such as lengthening of pauses and the speech segment, and a more deliberate, hyper-clear articulatory style. However, children’s speech also displayed large increases in amplitude that are not typical of adult hyperarticulation, as well as substantially larger magnitude adaptations than those observed in adult speech. These results corroborate and generalize the Computer-elicited Hyperarticulate Adaptation Model, and have implications for improved error handling in next-generation spoken language and multimodal systems. [Work supported by NSF Grant No. IIS-0117868.]
Acoustic characteristics of listener-constrained speech
Authors: Ashby Simone , Cummins Fred
Published: October 2013

Relatively little is known about the acoustical modifications speakers employ to meet the various constraints—auditory, linguistic and otherwise—of their listeners. Similarly, the manner by which perceived listener constraints interact with speakers’ adoption of specialized speech registers is poorly Hypo (H&H) theory offers a framework for examining the relationship between speech production and output-oriented goals for communication, suggesting that under certain circumstances speakers may attempt to minimize phonetic ambiguity by employing a ‘‘hyperarticulated’’ speaking style (Lindblom, 1990). It remains unclear, however, what the acoustic correlates of hyperarticulated speech are, and how, if at all, we might expect phonetic properties to change respective to different listener-constrained conditions. This paper is part of a preliminary investigation concerned with comparing the prosodic characteristics of speech produced across a range of listener constraints. Analyses are drawn from a corpus of read hyperarticulated speech data comprising eight adult, female speakers of English. Specialized registers include speech to foreigners, infant-directed speech, speech produced under noisy conditions, and human-machine interaction. The authors gratefully acknowledge financial support of the Irish Higher Education Authority, allocated to Fred Cummins for collaborative work with Media Lab Europe.
Characterization of the left/right bearing ambiguities for passive line arrays
Authors: Boyle Frank A. , Grant David E.
Published: October 2013

The symmetry of a straight line underwater acoustic array produces a left/right bearing ambiguity that makes it impossible to determine which side of the array a source is located on. A simple technique for resolving left/right ambiguities is to break the symmetry by curving the array. Under certain common conditions, however, significantly curved arrays still possess left/right ambiguities that depend on the source’s range and the beamformer’s focal length. These ambiguities can be modeled, given a source and array configuration, to produce a prediction of source localization capability. A map can be generated that indicates the spatial regions where a source is likely to be localized on the incorrect side of the array. The presentation will include a description of how the ambiguities are modeled, and simulated results. Considerations on how curved arrays can be configured to minimize ambiguities will be discussed.
Beamforming for a microphone array embedded in asymmetrically shaped objects
Authors: Moquin Philippe , Dedieu Stéphane , Goubran Rafik
Published: October 2013

Broadband frequency invariant beamforming for circular arrays or linear arrays are quite common but not when they are embedded in a diffracting structure. Meyer [J. Acoust. Soc. Am. 109, 185–193 (2001)] describes arrays embedded in a diffracting sphere, and provides an analytical solution for the wave equation in acoustics. For arrays of simple shape like circular rings embedded in a more complex shape one must make use of numerical methods (e.g., boundary element methods). Microphone arrays in shapes that are not symmetric or axisymmetric can also be solved this way but result in very asymmetrical beams. One example of such an obstacle is a telephone incorporating a microphone array. This presentation will show results from simulations and measurements of a six-microphone array. A design approach to obtain reasonably well behaved beams relies on constrained optimization, with a constraint build using a set of vectors containing the sensor signal for acoustic waves with specific directions of arrival. [Work supported in part by Carleton University.]
Underwater sand acoustics: A perspective derived from the sediment acoustics experiment (SAX99)
Authors: Williams Kevin L. , Thorsos Eric I. , Jackson Darrell R. , Tang Dajun , Kargl Steve G.
Published: October 2013

The sediment acoustics experiment (SAX99) included investigations of the following three questions. What are the dominant mechanisms responsible for backscattering from sand sediment? What are the dominant mechanisms responsible for subcritical penetration into sand? What are the appropriate constitutive equations for sand? In this paper a summary is presented of APL-UW SAX99 experiments and data/model comparisons relevant to each question. Perspectives are also given on some of the issues that remain or arose during SAX99 and the associated analyses. In general, these issues are tied to the frequency dependencies seen in the data but not fully captured by present models. For backscattering the issue is that as the frequency increases the measured backscattering strength does not follow predictions based on surface roughness scattering models. In the case of penetration it is a frequency cutoff effect seen in SAX99 buried array data but seemingly violated in the detection of buried objects near the SAX99 site. Regarding the constitutive equations, it is the frequency dependence of the attenuation above 50 kHz. Recent experiments will be described that have been motivated by these issues. Finally, research proposed as part of a follow-on sediment acoustics experiment (SAX04) will be outlined. [Work supported by ONR.]
Time domain modeling of seafloor scatter at low grazing angle using the small slope approximation
Authors: Pouliquen Eric , Pautet Lucie , Canepa Gaetano
Published: October 2013

Sea surface and bottom scattering components are usually quantified only in terms of scattering strength (SS). The SS corresponds to an ensemble averaged plane wave intensity scattered from a unit surface at a unit distance. However for non-steady-state cases when the acoustic footprint approaches the size of the acoustic wavelength, higher moment statistics and probability distribution functions (PDF) provide additional and essential information for detection and classification purposes. As a step toward higher moment scattering prediction the time domain model BORIS [Pouliquen et al., J. Acoust. Soc. Am. 105 (1999)] has been extended to low grazing angles. It uses the fourth-order small slope approximation (SSA-4) and the small perturbation theory for interface and volume scattering, respectively. This bistatic 3-D model accounts for the full sensing geometry and sonar properties. It uses stochastic realizations of the boundaries and volumes with controlled statistics. BORIS-SSA offers numerous possibilities for practical applications. In particular it provides an objective assessment of detection and classification performances for most current sonar systems (conventional and synthetic aperture sonars) operating in realistic and complicated environments (cluttered or patchy). The model principles and simulation results will be presented and illustrated with real sonar data.
Tempo and scale of biogenic effects on high-frequency acoustic propagation near the marine sediment–water interface in shallow water
Authors: Jumars Peter
Published: October 2013

Organisms have natural scales, such as lifetimes, body sizes, frequencies of movement to new locations, and residence times of material in digestive systems, and each scale has potential implications for acoustic effects. The effects of groups of organisms, like organisms themselves, aggregate in space and time. This review, including an assortment of unpublished information, examines examples of such aggregations, many of them documented acoustically. Light synchronizes many activities. Macroscopic animals forage primarily under cover of darkness. This phasing applies both to animals that extend appendages above the sediment–water interface and to animals that leave the seabed at night. Whereas their bottom-modifying activities are concentrated in nocturnal or crepuscular fashion, the bottom-modifying activities of the visual feeders follow a different phasing and often dominate the rate of change in acoustic backscatter from the interface. Light also acts through its effects on primary production, often concentrated in a very thin surficial layer atop the seabed. The supersaturation of oxygen does, and microbubble nucleation may, result. Where tidal velocities are large, light-set patterns are often tidally modulated. Activities of animals living below the seabed, however, remain a mystery, whose primary hope for solution is acoustic. [Work supported by ONR and DEPSCoR.]
Time and space scales of bedform evolution in sandy nearshore and inner shelf environments
Authors: Hay Alex E.
Published: October 2013

Recent experiments in wave-forced nearshore and inner shelf environments have demonstrated through acoustic and optical imaging techniques a remarkable range of bedform patterns in mobile sandy sediments at sub-10 m horizontal scales. The observed bedstates differ both in the level of complexity of their spatial patterns, and in the time scales of their response to changes in hydrodynamic forcing conditions. Yet, the (re)occurrence of these different bed states at a given location can be quite repeatable and, once formed, the migration of the bedforms characterizing a particular state can in some instances be predicted reasonably well from the local hydrodynamics. These results provide a basis against which the present capability for predicting bedstate evolution in wave-forced mobile bed environments can be assessed. It is argued that, with the possible exception of a few simple cases, current models are able to predict neither the level of complexity in the observed characteristic patterns, nor the time evolution of the bed given the prior history of the forcing. Nevertheless, the repeatability of bedstate occurrence, and the reasonably good predictions of migration velocity and shear stress at the bed, together suggest that such a predictive capability may be achievable in the not-too-distant future.
Exploiting sediment acoustics properties for subcritical buried target detection using a synthetic aperture sonar aboard the AUV Reliant
Authors: Commander Kerry W. , Fernandez Jose E. , Piper John E. , Stroud John S.
Published: October 2013

The Coastal Systems Station High Frequency/ Low Frequency Synthetic Aperture Sonar (HF/LFSAS) was recently integrated into a Bluefin Robotics, Inc. Odyssey III Family autonomous underwater vehicle (AUV). This vehicle, designated Reliant, has been used in several at-sea experiments to determine the feasibility of using bottom roughness to enhance detection of buried targets at subcritical grazing angles. Previously, the HF/LFSAS was deployed on a towed 21-in. vehicle and made some remarkable buried target detections at subcritical angles. However, due to the complexities associated with using a towed platform, only a limited amount of data was obtained during these exercises. This sparse data set made it difficult to quantify the enhancing effects of bottom roughness on buried target detection. An extensive run matrix for buried target detection was completed this year using the Reliant AUV. The primary variables in the experiments were ripple orientation, standoff range, and grazing angle. Results from these sea tests are presented and compared to theoretical models.
Variation of sea-bed backscattering strength due to Bragg scattering
Authors: Commander K. W. , Lopes J. L. , Lim R.
Published: October 2013

Bragg scattering from a rippled sea-bed may lead to reduced SNRs from proud targets, which adversely affects sonar performance. To quantify this effect, acoustic backscatter from a rippled bottom is investigated in the frequency range of 2–10 kHz by conducting a laboratory-type experiment to measure the reverberation levels from a bottom with a rippled interface. The experiment was performed in a 13.7-m deep, 110-m long, 80-m wide test pool that has 1.5 m of sand covering the bottom. In this experiment a calibrated parametric sonar was attached to a tower that was fitted with horizontal pan and vertical tilt motors. The rippled bottom was artificially formed with the aid of a sand scraper that consists of a frame and a rake that glides along the frame [Lopes et al., ‘‘Shallow Grazing Angle Sonar Detection of Targets Buried Under a Rippled Sand Interface,’’ Oceans 2002 MTS/IEEE, pp. 461–467]. The bottom backscatter measurements are compared to predictions of a model in which the interface roughness is represented by a Gaussian spectrum centered on the imposed ripple frequency band.
Teaching room acoustics as a product sound quality issue
Authors: Kleiner Mendel , Vastfjall Daniel
Published: October 2013

The department of Applied Acoustics teaches engineering and architect students at Chalmers University of Technology. The teaching of room acoustics to architectural students has been under constant development under several years and is now based on the study of room acoustics as a product sound quality issue. Various listening sessions using binaural sound recording and reproduction is used to focus students’ learning on simple, easy to remember concepts. Computer modeling using ray tracing software and auralization is also used extensively as a tool to demonstrate concepts in addition to other software for simple sound generation and manipulation. Sound in general is the focus of an interdisciplinary course for students from Chalmers as well as from a school of art, a school of design, and a school of music which offers particular challenges and which is almost all listening based.
Acoustics class at Berklee College of Music
Authors: Hoover Anthony K.
Published: October 2013

Berklee College of Music (in Boston) was developing its outstanding Music Technologies Division, and understood the need for a comprehensive class on acoustics. The result was a three-credit-hour class, offered twice per year, covering the fundamentals, architectural acoustics (outdoors, indoors, and transmission), vibration isolation, hearing and psychoacoustics, and more. One outgrowth was the Acoustical Society at Berklee, with presentations by local and visiting ASA members, yearly visits to an anechoic chamber, special studio sessions, tours, and joint meetings with professional societies. Over 2000 students have completed and performed well in the class. The author’s favorite measure of success is the growing number of students who have chosen a career in acoustics. This paper will summarize and discuss this class.
Studio-based courses in architectural acoustics
Authors: Siebein Gary W.
Published: October 2013

Examples of 4 nontraditional, elective courses offered to students in the Master of Architecture, Master of Science and Doctor of Philosophy degree programs in architecture are presented. Listening to Buildings involves experiential exercises in architectural acoustics for undergraduate students in a required large lecture course to form links between what people hear in a room and the architectural shapes and materials of the room that affects what is heard. The Applied Acoustics Design Lab takes students through each of the major components of an actual consulting project. Student work includes room acoustic design, sound isolation design, sound system design and HVAC noise control design for an actual building project. An Acoustical History of Theaters and Concert Halls teaches fundamentals of computer-based acoustic modeling and has students compare the physical design and aural simulations of a historic and a contemporary performance space. Graduate design studio in acoustics examines sound and silence as potential form-givers in architecture and as generative ideas for the basis of architectural interventions in complex sites and programs. Interior and exterior soundscapes and phenomenological philosophy form the background research for the studio.
Teaching noise control to architectural engineers
Authors: Muehleisen Ralph T.
Published: October 2013

Architectural engineers have to deal with acoustics in a variety of situations. HVAC engineers, structural engineers, safety engineers, lighting engineers, and construction engineers all need to be aware of noise, vibration, sound transmission, and general room acoustics. In this talk, the teaching of acoustics to architectural engineers is presented. In particular, the talk will focus on how to teach useful building noise control and architectural acoustics to architectural engineers with no previous background in acoustics and who may be less mathematically adept than other engineers or physicists.
A real challenge: Teaching acoustics to architecture students
Authors: Raichel Daniel R.
Published: October 2013

The key to instilling the fundamentals of acoustics in architecture students is to arouse their interest. Because so many of the students are interested in music and high-fidelity equipment, it does not take much to ignite their interest in acoustics, particularly when they come to realize that perfectly good equipment can be undermined by poor room acoustics. Because they generally are not comfortable with mathematics, having had received perhaps no more than one or two semesters of introductory calculus; they need to be spoon-fed mathematics, even to the point of reviewing logarithmic manipulations, which are normally taught in secondary schools. The purpose of teaching acoustics to architects is not to make them acoustic experts, per se, but to make them appreciative of the effect of room acoustics and to understand that they must work hand-in-hand with acousticians when they design listening spaces that range in size from small classrooms to lecture halls to large concert halls. A regular acoustics text, such as that by Beranek, or Kinsler and Frey, or Raichel would be beyond the scope of an architectural course, but a text written especially for nonscience majors (such as that by Apfel) should and did serve admirably.
The use of lattice gas method in explaining architectural acoustics principles
Authors: Yoon Sung Y. , Smith Dana M.
Published: October 2013

Many concepts in architectural acoustics are based on physical phenomena, such as sound propagation, reflection, etc. In explaining those phenomena, it is necessary to employ the principles of physical acoustics. Unfortunately, the methods of physical acoustics are not easily approachable unless one is familiar with mathematical physics techniques, partial differential equations, for example. The lattice gas method, based on the cellular automata concept, can be an alternative to avoid the use of complicated mathematical equations. A relatively simple code can be used to generate computer simulations. The existing models for sound propagation by Sudo and Sparrow, are examined. Models for other phenomena involving architectural acoustics are suggested.
Nonlinear phenomena in northern mockingbird (Mimus polyglottos) vocalizations: Acoustics and physiology
Authors: Zollinger Sue Anne , Riede Tobias , Suthers Roderick A.
Published: October 2013

The bird sound source (syrinx), like the mammalian larynx, has been discovered to behave as a nonlinear system of coupled oscillators. Modeling approaches as well as excised syrinx experiments show that the syrinx can be considered a nonlinear sound source. Until now, only few acoustic data were available showing to what extent a birdsong species’ vocal repertoire actually contains nonlinear phenomena, like subharmonics, frequency jumps, biphonation and deterministic chaos. The passerine syrinx, in contrast to the mammalian larynx, consists of two sound sources, one situated in each of the bronchi that are independently controlled. Bronchial airflow measurements showed that individual mockingbirds use each side of the syrinx independently. However, there are interactions of both sound sources, which have not yet been investigated acoustically/spectrographically. The present study shows how many of the spectrographically observed nonlinear phenomena are attributed to the interaction of the two sound sources, i.e., nonlinear phenomena, while both sound sources show positive airflow values, compared to single sound source utterances, i.e., positive flow through one sound source only. Nonlinear phenomena could be attributed to the interaction of the two sound sources (earlier referred to as ‘‘two-voice-phenomenon’’) but were also found to be produced by a single sound source.
Intensity discrimination as a function of level and frequency in three species of birds
Authors: Lauer Amanda M. , Poling Kirsten , Dooling Robert J.
Published: October 2013

Many studies have examined frequency discrimination in birds, but there has not been as complete a description of avian intensity discrimination abilities. Birds appear to be slightly less sensitive to changes in intensity than humans and other mammals; however, few studies have systematically looked at the effects of both frequency and presentation level on intensity discrimination in birds. Here we describe intensity discrimination as a function of frequency and sensation level in two small songbird species, the canary (Serinus canarius), the zebra finch (Taeniopygia guttata), and a nonsongbird species, the budgerigar (Melopsittacus undulatus). Intensity difference limens (DLIs) for pure tones were obtained from birds using standard operant conditioning procedures and the Method of Constant Stimuli. DLIs ranged from approximately 2–6 dB, which are slightly larger than the DLIs reported in mammals. For all three species, DLIs become smaller with increasing presentation level, but show little effect across frequency for a given level. These results are consistent with previous reports in other species. [Work supported by NIH DC01372 to RJD and DC05450 to AML.]
Sound localization of aerial broadband noise in pinnipeds
Authors: Holt Marla M. , Schusterman Ronald J. , Kastak David , Southall Brandon L.
Published: October 2013

Pinnipeds (seals, sea lions, and walruses) emit broadband calls on land as part of their communication system in order to coordinate their reproductive activities. How well do they localize these types of signals? In this study, the aerial sound localization acuities of a harbor seal (Phoca vitulina), a California sea lion (Zalophus californianus), and a northern elephant seal (Mirounga angustirostris) were measured in the horizontal plane with a broadband white noise stimulus. Testing was conducted in a hemi-anechoic chamber using a left/right forced choice procedure to measure the minimum audible angle (MAA) for each subject. MAAs were defined as half the angular separation of two sound sources relative to a subject’s midline that corresponded to 75% correct discrimination. MAAs were 3.6, 4.2, and 4.7 deg for the harbor seal, California sea lion, and northern elephant seal, respectively. These results demonstrate that these pinniped species had sound localization abilities comparable to the domestic cat and rhesus macaques. The acuity differences between our subjects were small, were not predicted by head size, and therefore likely reflect the relatively acute abilities of other pinniped species to localize aerial broadband signals.
Automated detection of sperm whale sounds as a function of abrupt changes in sound intensity
Authors: Walker Christopher D. , Rayborn Grayson H. , Brack Benjamin A. , Kuczaj Stan A. , Paulos Robin L.
Published: October 2013

An algorithm designed to detect abrupt changes in sound intensity was developed and used to identify and count sperm whale vocalizations and to measure boat noise. The algorithm is a Matlab routine that counts the number of occurrences for which the change in intensity level exceeds a threshold. The algorithm also permits the setting of a ‘‘dead time’’ interval to prevent the counting of multiple pulses within a single sperm whale click. This algorithm was used to analyze digitally sampled recordings of ambient noise obtained from the Gulf of Mexico using near bottom mounted EARS buoys deployed as part of the Littoral Acoustic Demonstration Center experiment. Because the background in these data varied slowly, the result of the application of the algorithm was automated detection of sperm whale clicks and creaks with results that agreed well with those obtained by trained human listeners. [Research supported by ONR.]
Behavior of dusky dolphins foraging on the deep-scattering layer in Kaikoura Canyon, New Zealand
Authors: Benoit-Bird Kelly , Wursig Bernd , McFadden Cynthia
Published: October 2013

Little is known of foraging habits of sound-scattering layer consumers. A 200-kHz echosounder was used to survey dusky dolphins and the sound-scattering layer in winter 2002, in Kaikoura Canyon, New Zealand. Visual observations of dolphin surfacings occurred 84% of the time that dolphins were acoustically detected, confirming identifications from the acoustic data. Dusky dolphins were within the layer at 2000 h (about 1.5 h after dusk), within 125 m of the surface. As the layer rose to within 30 m of the surface at 0100 h, the observed depth of dolphins decreased presumably as the dolphins followed the vertical migration of their prey. The mean depth of dolphins was within the scattering layer except when the top of the layer was deeper than 125 m. Dusky dolphins often forage within large groups. Acoustically identified subgroups of coordinated animals ranged from 1 to 5 dolphins. Subgroup size varied with time of night, minimum depth of the scattering layer, and the variance of the food resource. The largest subgroups occurred when the scattering layer was closest to the surface, and when the layer was most heterogeneous. Time, depth of layer, and layer variance contributed significantly to predicting foraging dusky dolphin subgroup size.
Head sinuses, melon, and jaws of bottlenose dolphins, Tursiops truncatus, observed with computed tomography structural and single photon emission computed tomography functional imaging
Authors: Ridgway Sam , Houser Dorian , Finneran James J. , Carder Don , Van Bonn William , Smith Cynthia , Hoh Carl , Corbeil Jacqueline , Mattrey Robert
Published: October 2013

The head sinuses, melon, and lower jaws of dolphins have been studied extensively with various methods including radiography, chemical analysis, and imaging of dead specimens. Here we report the first structural and functional imaging of live dolphins. Two animals were imaged, one male and one female. Computed tomography (CT) revealed extensive air cavities posterior and medial to the ear as well as between the ear and sound-producing nasal structures. Single photon emission computed tomography (SPECT) employing 50 mCi of the intravenously injected ligand technetium [Tc-99m] biscisate (Neurolite) revealed extensive and uptake in the core of the melon as well as near the pan bone area of the lower jaw. Count density on SPECT images was four times greater in melon as in the surrounding tissue and blubber layer suggesting that the melon is an active rather than a passive tissue. Since the dolphin temporal bone is not attached to the skull except by fibrous suspensions, the air cavities medial and posterior to the ear as well as the abutment of the temporal bone, to the acoustic fat bodies of each lower jaw, should be considered in modeling the mechanism of sound transmission from the environment to the dolphin ear.
Concentric scheme of monkey auditory cortex
Authors: Kosaki Hiroko , Saunders Richard C. , Mishkin Mortimer
Published: October 2013

The cytoarchitecture of the rhesus monkey’s auditory cortex was examined using immunocytochemical staining with parvalbumin, calbindin-D28K, and SMI32, as well as staining for cytochrome oxidase (CO). The results suggest that Kaas and Hackett’s scheme of the auditory cortices can be extended to include five concentric rings surrounding an inner core. The inner core, containing areas A1 and R, is the most densely stained with parvalbumin and CO and can be separated on the basis of laminar patterns of SMI32 staining into lateral and medial subdivisions. From the inner core to the fifth (outermost) ring, parvalbumin staining gradually decreases and calbindin staining gradually increases. The first ring corresponds to Kaas and Hackett’s auditory belt, and the second, to their parabelt. SMI32 staining revealed a clear border between these two. Rings 2 through 5 extend laterally into the dorsal bank of the superior temporal sulcus. The results also suggest that the rostral tip of the outermost ring adjoins the rostroventral part of the insula (area Pro) and the temporal pole, while the caudal tip adjoins the ventral part of area 7a.
Detection theory applied to high intensity focused ultrasound (HIFU) treatment evaluation
Authors: Sanghvi Narendra , Wunderlich Adam , Seip Ralf , Tavakkoli Jahangir , Dines Kris , Baily Michael , Crum Lawrence
Published: October 2013

The aim of this work is to develop a HIFU treatment evaluation algorithm based on 1-D pulse/echo (P/E) ultrasound data taken during HIFU exposures. The algorithm is applicable to large treatment volumes resulting from several overlapping elementary exposures. Treatments consisted of multiple HIFU exposures with an on-time of 3 seconds each, spaced 3 mm apart, and an off-time of 6 seconds in between HIFU exposures. The HIFU was paused for approximately 70 milliseconds every 0.5 seconds, while P/E data was acquired along the beam axis, using a confocal imaging transducer. Data was collected from multiple in vitro and in vivo tissue treatments, including shams. The cumulative energy change in the P/E data was found for every HIFU exposure, as a function of depth. Subsequently, a likelihood ratio test with a fixed false alarm rate was used to derive a positive or negative lesion creation decision for that position. For false alarm rates less than 5%, positive treatment outcomes were consistently detected for better than 90% of the HIFU exposures. In addition, the algorithm outcome correlated to the applied HIFU intensity level. Lesion formation was therefore successfully detected as a function of dosage. [Work supported by NIH SBIR Grant 2 R 44 CA 83244-02.]
Study of a scanning HIFU therapy protocol, Part II: Experiment and results
Authors: Andrew Marilee A. , Kaczkowski Peter , Cunitz Bryan W. , Brayman Andrew A. , Kargl Steven G.
Published: October 2013

Instrumentation and protocols for creating scanned HIFU lesions in freshly excised bovine liver were developed in order to study the in vitro HIFU dose response and validate models. Computer-control of the HIFU transducer and 3-axis positioning system provided precise spatial placement of the thermal lesions. Scan speeds were selected in the range of 1 to 8 mm/s, and the applied electrical power was varied from 20 to 60 W. These parameters were chosen to hold the thermal dose constant. A total of six valid scans of 15 mm length were created in each sample; a 3.5 MHz single-element, spherically focused transducer was used. Treated samples were frozen, then sliced in 1.27 mm increments. Digital photographs of slices were downloaded to computer for image processing and analysis. Lesion characteristics, including the depth within the tissue, axial length, and radial width, were computed. Results were compared with those generated from modified KZK and BHTE models, and include a comparison of the statistical variation in the across-scan lesion radial width. [Work supported by USAMRMC.]