bluuebunny/crossref_metadata_2025 huggingface dataset:
The upper limit of temporal pitch for cochlear-implant listeners: Stimulus duration, conditioner pulses, and the number of electrodes stimulated
Authors: Carlyon Robert P. , Deeks John M. , McKay Colette M.
Published: March 2010

Three experiments studied discrimination of changes in the rate of electrical pulse trains by cochlear-implant (CI) users and investigated the effect of manipulations that would be expected to substantially affect the pattern of auditory nerve (AN) activity. Experiment 1 used single-electrode stimulation and tested discrimination at baseline rates between 100 and 500 pps. Performance was generally similar for stimulus durations of 200 and 800 ms, and, for the longer duration, for stimuli that were gated on abruptly or with 300-ms ramps. Experiment 2 used a similar procedure and found that no substantial benefit was obtained by the addition of background 5000-pps “conditioning” pulses. Experiment 3 used a pitch-ranking procedure and found that the range of rates over which pitch increased with increasing rate was not greater for multiple-electrode than for single-electrode stimulation. The results indicate that the limitation on pulse-rate discrimination by CI users, at high baseline rates, is not specific to a particular temporal pattern of the AN response.
Perception of final fricative voicing: Native and nonnative listeners’ use of vowel duration
Authors: Broersma Mirjam
Published: March 2010

Does experience with a perceptual cue for a phoneme contrast in the native language affect its use in a second language for a similar contrast in a different phonetic context? Two experiments investigated Dutch and English listeners’ use of preceding vowel duration as a perceptual cue for nonword-final fricative voicing in English. Dutch listeners have native language experience with the use of vowel duration for vowel length and intervocalic obstruent voicing contrasts, but not for final voicing contrasts, as Dutch does not have voiced obstruents word-finally. Previous research [Broersma, M. (2005). J. Acoust. Soc. Am. 117, 3890–3901; Broersma, M.(2008) J. Acoust. Soc. Am.124, 712–715] showed that Dutch listeners used vowel duration less for final /v-f/ categorization than English listeners did when vowel duration varied only between subjects, discouraging its use as a perceptual cue. The present study assessed the use of vowel duration for final /v-f/ and /z-s/ contrasts when it varied within subjects. A goodness rating and a phonetic categorization experiment showed that Dutch listeners used vowel duration, but less than English listeners did. Thus, experience with a perceptual cue for a different contrast and for a similar contrast in a different position in the native language did not lead to native-like use of this cue in the second language.
A reanalysis of McGurk data suggests that audiovisual fusion in speech perception is subject-dependent
Authors: Schwartz Jean-Luc
Published: March 2010

Audiovisual perception of conflicting stimuli displays a large level of intersubject variability, generally larger than pure auditory or visual data. However, it is not clear whether this actually reflects differences in integration per se or just the consequence of slight differences in unisensory perception. It is argued that the debate has been blurred by methodological problems in the analysis of experimental data, particularly when using the fuzzy-logical model of perception (FLMP) [Massaro, D. W. (1987). Speech Perception by Ear and Eye: A Paradigm for Psychological Inquiry (Laurence Erlbaum Associates, London)] shown to display overfitting abilities with McGurk stimuli [Schwartz, J. L. (2006). J. Acoust. Soc. Am. 120, 1795–1798]. A large corpus of McGurk data is reanalyzed, using a methodology based on (1) comparison of FLMP and a variant with subject-dependent weights of the auditory and visual inputs in the fusion process, weighted FLMP (WFLMP); (2) use of a Bayesian selection model criterion instead of a root mean square error fit in model assessment; and (3) systematic exploration of the number of useful parameters in the models to compare, attempting to discard poorly explicative parameters. It is shown that WFLMP performs significantly better than FLMP, suggesting that audiovisual fusion is indeed subject-dependent, some subjects being more “auditory,” and others more “visual.” Intersubject variability has important consequences for theoretical understanding of the fusion process, and re-education of hearing impaired people.
Resistance to learning binaurally mismatched frequency-to-place maps: Implications for bilateral stimulation with cochlear implants
Authors: Siciliano Catherine M. , Faulkner Andrew , Rosen Stuart , Mair Katharine
Published: March 2010

Simulations of monaural cochlear implants in normal hearing listeners have shown that the deleterious effects of upward spectral shifting on speech perception can be overcome with training. This study simulates bilateral stimulation with a unilateral spectral shift to investigate whether listeners can adapt to upward-shifted speech information presented together with contralateral unshifted information. A six-channel, dichotic, interleaved sine-carrier vocoder simulated a binaurally mismatched frequency-to-place map. Odd channels were presented to one ear with an upward frequency shift equivalent to 6 mm on the basilar membrane, while even channels were presented to the contralateral ear unshifted. In Experiment 1, listeners were trained for 5.3 h with either the binaurally mismatched processor or with just the shifted monaural bands. In Experiment 2, the duration of training was 10 h, and the trained condition alternated between those of Experiment 1. While listeners showed learning in both experiments, intelligibility with the binaurally mismatched processor never exceeded, intelligibility with just the three unshifted bands, suggesting that listeners did not benefit from combining the mismatched maps, even though there was clear scope to do so. Frequency-place map alignment may thus be of importance when optimizing bilateral devices of the type studied here.
Modulation of ultrasound to produce multifrequency radiation force
Authors: Urban Matthew W. , Fatemi Mostafa , Greenleaf James F.
Published: March 2010

Dynamic radiation force has been used in several types of applications, and is performed by modulating ultrasound with different methods. By modulating ultrasound, energy can be transmitted to tissue, in this case a dynamic force to elicit a low frequency cyclic displacement to inspect the material properties of the tissue. In this paper, different types of modulation are explored including amplitude modulation (AM), double sideband suppressed carrier amplitude modulation AM, linear frequency modulation, and frequency-shift keying. Generalized theory is presented for computing the radiation force through the short-term time average of the energy density for these various types of modulation. Examples of modulation with different types of signals including sine waves, square waves, and triangle waves are shown. Using different modulating signals, multifrequency radiation force with different numbers of frequency components can be created, and can be used to characterize tissue mimicking materials and soft tissue. Results for characterization of gelatin phantoms using a method of vibrating an embedded sphere are presented. Different degrees of accuracy were achieved using different modulation techniques and modulating signals. Modulating ultrasound is a very flexible technique to produce radiation force with multiple frequency components that can be used for various applications.
Probing slow dynamics of consolidated granular multicomposite materials by diffuse acoustic wave spectroscopy
Authors: Tremblay Nicolas , Larose Eric , Rossetto Vincent
Published: March 2010

The stiffness of a consolidated granular medium experiences a drop immediately after a moderate mechanical solicitation. Then the stiffness rises back toward its initial value, following a logarithmic time evolution called slow dynamics. In the literature, slow dynamics has been probed by macroscopic quantities averaged over the sample volume, for instance, by the resonant frequency of vibrational eigenmodes. This article presents a different approach based on diffuse acoustic wave spectroscopy, a technique that is directly sensitive to the details of the sample structure. The parameters of the dynamics are found to depend on the damage of the medium. Results confirm that slow dynamics is, at least in part, due to tiny structural rearrangements at the microscopic scale, such as inter-grain contacts.
The acoustical bright spot and mislocalization of tones by human listeners
Authors: Macaulay Eric J. , Hartmann William M. , Rakerd Brad
Published: March 2010

Listeners attempted to localize 1500-Hz sine tones presented in free field from a loudspeaker array, spanning azimuths from 0° (straight ahead) to 90° (extreme right). During this task, the tone levels and phases were measured in the listeners’ ear canals. Because of the acoustical bright spot, measured interaural level differences (ILD) were non-monotonic functions of azimuth with a maximum near 55°. In a source-identification task, listeners’ localization decisions closely tracked the non-monotonic ILD, and thus became inaccurate at large azimuths. When listeners received training and feedback, their accuracy improved only slightly. In an azimuth-discrimination task, listeners decided whether a first sound was to the left or to the right of a second. The discrimination results also reflected the confusion caused by the non-monotonic ILD, and they could be predicted approximately by a listener’s identification results. When the sine tones were amplitude modulated or replaced by narrow bands of noise, interaural time difference (ITD) cues greatly reduced the confusion for most listeners, but not for all. Recognizing the important role of the bright spot requires a reevaluation of the transition between the low-frequency region for localization (mainly ITD) and the high-frequency region (mainly ILD).
Two-microphone separation of speech mixtures based on interclass variance maximization
Authors: Cobos Maximo , Lopez Jose J.
Published: March 2010

Sparse methods for speech separation have become a discussed issue in acoustic signal processing. These sparse methods provide a powerful approach to the separation of several signals in the underdetermined case, i.e., when there are more sources than sensors. In this paper, a two-microphone separation method is presented. The proposed algorithm is based on grouping time-frequency points with similar direction-of-arrival (DOA) using a multi-level thresholding approach. The thresholds are calculated via the maximization of the interclass variance between DOA estimates and allow to identify angular sections, wherein the speakers are located with a strong likelihood. These sections define a set of time-frequency masks that are able to separate several sound sources in realistic scenarios and with little computational cost. Several experiments carried out under different mixing situations are discussed, showing the validity of the proposed approach.
Active control of one-dimension impulsive reflection based on a prediction method
Authors: Han Ning , Feng Shengzhen , Qiu Xiaojun
Published: March 2010

An approach for predicting the reflected sound pressure is proposed in one-dimensional sound field. For a duct ended with a rigid reflective surface, only one microphone is required to measure the total sound pressure on the surface, which is further used as the error sensing strategy in an active noise control (ANC) system to reduce the in-duct reflection. Experiments are carried out to validate the prediction method, and a broadband feedforward ANC system is implemented to suppress the impulsive reflection. It is found that the ANC system based on the reflected sound prediction is effective, and 12.2 dB attenuation of the one-dimension impulsive reflection is obtained after the active control.
Perceptual assessment of quality of urban soundscapes with combined noise sources and water sounds
Authors: Jeon Jin Yong , Lee Pyoung Jik , You Jin , Kang Jian
Published: March 2010

In this study, urban soundscapes containing combined noise sources were evaluated through field surveys and laboratory experiments. The effect of water sounds on masking urban noises was then examined in order to enhance the soundscape perception. Field surveys in 16 urban spaces were conducted through soundwalking to evaluate the annoyance of combined noise sources. Synthesis curves were derived for the relationships between noise levels and the percentage of highly annoyed (%HA) and the percentage of annoyed (%A) for the combined noise sources. Qualitative analysis was also made using semantic scales for evaluating the quality of the soundscape, and it was shown that the perception of acoustic comfort and loudness was strongly related to the annoyance. A laboratory auditory experiment was then conducted in order to quantify the total annoyance caused by road traffic noise and four types of construction noise. It was shown that the annoyance ratings were related to the types of construction noise in combination with road traffic noise and the level of the road traffic noise. Finally, water sounds were determined to be the best sounds to use for enhancing the urban soundscape. The level of the water sounds should be similar to or not less than 3 dB below the level of the urban noises.
On the subtraction method for in-situ reflection and diffusion coefficient measurements
Authors: Robinson Philip , Xiang Ning
Published: March 2010

The subtraction method is a technique critical to several important acoustic measurements. It involves subtracting a reference measurement including only direct sound from one with direct sound and a reflection, to isolate the reflection. The process is very sensitive to environmental conditions, such as changes in temperature, air movement, and microphone positioning. These variations cause small time differences between the reference and reflection measurements, which prevent complete subtraction of the direct sound; the residual direct sound then pollutes analysis of the isolated reflection. This work evaluates methods to compensate for differences to achieve minimal interference from the residual direct sound.
Influence of the ventricular folds on a voice source with specified vocal fold motion
Authors: McGowan Richard S. , Howe Michael S.
Published: March 2010

The unsteady drag on the vocal folds is the major source of sound during voiced speech. The drag force is caused by vortex shedding from the vocal folds. The influence of the ventricular folds (i.e., the “false” vocal folds that protrude into the vocal tract a short distance downstream of the glottis) on the drag and the voice source are examined in this paper by means of a theoretical model involving vortex sheets in a two-dimensional geometry. The effect of the ventricular folds on the output acoustic pressure is found to be small when the movement of the vocal folds is prescribed. It is argued that the effect remains small when fluid-structure interactions account for vocal fold movement. These conclusions can be justified mathematically when the characteristic time scale for change in the velocity of the glottal jet is large compared to the time it takes for a vortex disturbance to be convected through the vocal fold and ventricular fold region.
Three-dimensional nature of the glottal jet
Authors: Triep Michael , Brücker Christoph
Published: March 2010

The factors contributing to human voice production are not yet fully understood. Even normal human phonation with a symmetric glottal opening area is still the subject of extensive investigation. Among others, it has already been shown that fluid dynamics has a strong influence on the vocal process. The full characterization of the glottal jet has not been accomplished yet. Time-resolved measurement and visualization of the three-dimensional (3D) flow downstream the human vocal folds are difficult if not impossible to perform in vivo. Therefore, it is common to use mechanical and numerical models with a simplified shape and motion profile of the vocal folds. In this article, further results regarding the 3D flow structure obtained in a 3:1 up-scaled dynamic glottis model (cam model) in a water circuit are given, extending earlier work [M. Triep et al. (2005). Exp. Fluids 39, 232–245]. The model mimics the temporal variation in the 3D contour of the glottal gap while water flow reduces the characteristic frequencies by the order of 1/140. The unsteady flow processes downstream of the vocal folds are visualized in slow motion and analyzed in detail via particle imaging techniques. The visualization results show complex 3D flow behavior of lengthwise jet contraction and axis switching. In addition, the time-dependent flow rate during the phonatory oscillation cycle is measured in detail. It is shown that the pressure loss is decreased in the presence of a second constriction downstream of the glottis in form of ventricular folds and it is observed that for this case the jet is stabilized in the divergent phase of the cycle.
Unintended consequences: Acoustical outcomes in LEED (Leadership in Energy and Environmental Design) certified offices.
Authors: Powell Kevin
Published: March 2010

Recent research conducted by the US General Services Administration and the Center for the Built Environment at UC Berkeley disclosed an anomaly about “green building” interiors that is an unintended consequence of the current LEED rating system. The anomaly is this: occupants of offices that have been upgraded to achieve LEED certification express high levels of satisfaction with the “indoor environmental quality” of almost all attributes of these spaces; but there is one exception where occupant scores are lower than before. Their increased dissatisfaction has to do with acoustics and privacy. What is it about LEED-rated offices that cause increased dissatisfaction? Why are occupants uncomfortable with the “acoustical comfort” of the new LEED-certified offices? Is it because there are more reflective, hard surfaces—such as exposed ceilings—causing noise to reverberate? Or because HVAC systems have become quieter? Or because partition heights have been lowered to allow better airflow and more natural light, resulting in less privacy? Since increased occupant dissatisfaction may result in reduced productivity or increased absenteeism, the GSA’s Office of Research has been examining this issue and report on its findings and conclusions.
Acoustical materials for a green world: The sustainable design transformation of the architectural acoustics industry.
Authors: Kachur Mandy , Bruck Daniel , Hesedahl Jeanette
Published: March 2010

The focus on sustainable and healthy building materials has intensified over the last few years. This is true particularly in healthcare, educational, and environmentally friendly or “green,” facilities, where an increasing awareness of acoustics has resulted in a higher demand for innovative products. As the healthcare industry pushes for greater patient comfort, increased speech privacy, and green design, new acoustical products must satisfy multiple requirements. In educational facilities, the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) for Schools rating system promotes the use of green products, which extends to acoustical materials. Additionally, some educational facility owners are hesitant to allow traditional types of sound absorbers such as fiberglass duct liner for fear of health issues. Consequently, acoustical materials manufacturers have responded with new and repurposed materials to suit these needs. Because many of these materials have been recently introduced, a significant amount of project time can be expended on research to select an appropriate material to suit the new requirements. In an attempt to streamline the selection process, this overview will identify a number of these new and repurposed materials and provide feedback on their use from architects, engineers, and owners.
Green classroom acoustics: Sound or noise?
Authors: Sweitzer Glenn E.
Published: March 2010

Architectural acoustics is underrepresented in current green building rating systems. While acoustics factors are embodied in green building issues, their scoring potentials remain untapped. An alternative, individual user-oriented basis is tested for scoring architectural acoustics factors. Key architectural acoustics factors embodied in the currently prevailing LEED Green Building Rating System are identified. Selected acoustics factors, and relevant criteria, are studied in the context of four similar school classrooms in one K-5 school. To assess the relative values of these factors, four K-5 teachers are surveyed and then interviewed regarding sound and noise control strategies used in their respective classrooms by academic subject, visual and aural media, and teacher-student and student-student configurations. Reported outcomes are compared with measured sound transmission index (STI) values for selected activity configurations in each classroom. Results suggest that passive sound and noise control in individual classrooms can be used to improve STI by academic subject, presentation media, and teacher and student configurations. Accordingly, scoring for an individual classroom will vary by the passive as well as active noise control means used. Examples are discussed.
Acoustic compensation to shipping and airgun noise by Mediterranean fin whales (Balaenoptera physalus).
Authors: Castellote Manuel , Clark Cristopher W. , Lammers Marc O.
Published: March 2010

Seafloor recorders were deployed in the western Mediterranean Sea and adjacent Atlantic waters during 2006–2009 to monitor noise levels and fin whale presence. Acoustic parameters of 20-Hz pulses (pulse duration, bandwidth and intervals, and center and peak frequencies) were compared for areas with different shipping noise levels, different shipping intensities in the Strait of Gibraltar and during seismic airgun events. Statistically significant differences were detected between noise contexts. In general, acoustic parameter values decreased with increased noise levels. In high-noise conditions, 20-Hz pulse duration shortened, bandwidth decreased, and center and peak frequencies decreased. Similar results were obtained in the presence of airgun events, and bearings to singing whales indicated that whales moved away from the airgun source and out of our detection area for a time period that extended well beyond the duration of the airgun activity. This study provides evidence that fin whales modify their acoustic behavior to compensate for increased ambient noise and shows that under some conditions they will leave an area for an extended period. Sensitization and habituation processes may play a role in these behaviors and are discussed in the context of these results.
Anthropogenic noise and sound production by beluga whales (Delphinapterus leucas) in Cook Inlet, Alaska during early August 2007.
Authors: Hotchkin Cara F. , Parks Susan E. , Mahoney Barbara A.
Published: March 2010

The beluga whale population in Cook Inlet, Ak, has a limited range centered near the Port of Anchorage and was declared endangered in 2008. One potential threat to the belugas recovery is anthropogenic noise, which may disrupt communication and normal behaviors. This project used a boat-based single hydrophone system to evaluate noise levels at several locations in Cook Inlet on 6 days from 2–14 August, 2007. Belugas were encountered twice, at the Port of Anchorage and near the Little Susitna River. Recorded vocalizations were analyzed to develop a provisional description of the whales’ repertoire. Call frequencies ranged from 381 Hz to 24 kHz (the limit of the recording system), with most energy at frequencies above 2 kHz. Most vocalizations were similar to call types of other beluga populations. Broadband and 1/3-octave band levels were evaluated for noise from tidal flow and ships at the Port of Anchorage. Vessel noise levels were highest below 0.5 kHz, but frequencies ranged to greater than 8 kHz (distance to source < 200 m). Based on the overlap in frequency between beluga vocalizations and ship noise, anthropogenic sound may mask beluga communication near vessels in Cook Inlet.
Cook Inlet beluga whale echolocations at the Port of Anchorage expansion.
Authors: Širović Ana , Kendall Lindsey S.
Published: March 2010

Ocean noise levels increase as a result of human activities. As a result, the effects of anthropogenic noise on marine mammals are a growing concern. A genetically distinct population of beluga whales in Cook Inlet was listed as endangered under the Endangered Species Act in 2008. NOAA has identified many potential threats to the Cook Inlet beluga whale population, including coastal development and anthropogenic noise. The Port of Anchorage Marine Terminal Redevelopment Project, currently underway in Upper Cook Inlet, involves several types of water construction activities, including pile driving. However, the effect of pile driving noise on beluga whales is unknown. A passive acoustic array of sonobuoys was deployed during 20 days in August and September 2009 to acoustically detect the presence of beluga whales in the vicinity of in-water pile driving at the Port project site. Beluga whale echolocation clicks were detected on days when the whales were also visually sighted by the on-site visual observers. Whistles and burst pulses were not commonly detected from beluga whales in this area.
The accessible Arctic Ocean.
Authors: Farrell John W.
Published: March 2010

Scientific evidence indicates that global climate changes, and the most rapid changes are in the Arctic. Northern temperatures have increased twice as fast as elsewhere, the areal extent and thickness of Arctic sea ice have decreased dramatically, sea level rises as oceans warm and as glaciers and icesheets melt, and the ocean becomes more acidic as it absorbs atmospheric carbon dioxide. Changes in climate, as well as advances in technology, and the demand for resources have resulted in a newly accessible Arctic Ocean that invites to commercial fishing, shipping, tourism, mineral, and energy extraction interests and catches the attention of the US Coast Guard and the US Navy, among others. Many activities associated with these interests have implications for sound in the sea, and this presentation will present some of these at an overarching level. The United States has barely begun the baseline oceanographic research necessary to support national and international goals for ecosystem-based management and marine spatial planning in the Arctic Ocean. The US Arctic Research Commission, an independent federal agency, that advises Congress and the Executive Branch calls for Arctic Ocean research that would help policy makers address these issues.
Feasibility study of superharmonic imaging using chirps.
Authors: van Neer Paul L. M. J. , Danilouchkine Mike G. , Matte Guillaume M. , Verweij Martin D. , de Jong Nico
Published: March 2010

Superharmonic imaging (SHI) targets a combination of the third to fifth harmonics. It was proven to have certain advantages in comparison with the established imaging standards in medical ultrasound. SHI enhances the spatial resolution and improves the quality of echographic images, mainly by eliminating reverberation artifacts at the chest wall. However, SHI suffers from ripple artifacts, originating from the spectral gaps in between harmonics, and degrading the temporal resolution. To solve this a chirp-based SHI protocol was employed and its characteristics investigated, i.e., point spread function (PSF). The protocol was implemented for an interleaved phased array probe (44+44 elements tuned at 1.0+3.7 MHz), connected to a fully programmable ultrasound system. A linear chirp (center frequency 1 MHz; bandwidth 40%) was used for excitation. To obtain the PSF, the rf traces were recorded at focus along the lateral axis and convolved with the decoding signal. This was computed using KZK simulations. A PSF comparison between a superharmonic chirp and the third harmonic of a 2.5-cycle Gaussian apodized sinus burst at 1 MHz showed a decrease in axial pulse length of 46% at −6 dB and 32% at the −20 dB level in favor of SHI. Chirp based SHI is virtually free of ripple artifacts and therefore feasible.
Inter-comparison of ultrasonic backscatter coefficient measurements of live rat fibroadenomas across multiple imaging platforms.
Authors: Wirtzfeld Lauren A. , Ghoshal Goutam , Hafez Zachary T. , Nam Kibo , Labyed Yassin , Anderson Janelle A. , Herd M-Teresa , Miller Rita J. , Sawarte Sandhya , Zagzebski James A. , Bigelow Timothy A. , Hall Timothy J. , Oelze Michael L. , O'Brien William D.
Published: March 2010

The backscatter coefficient (BSC) as a function of frequency is a system and operator independent parameter. It is the basis for some quantitative ultrasound (QUS) based on spectral analysis being translated into clinical use. This study aims to extend previous work in well-characterized physical phantoms to live animals where tissue properties are unknown. Six Sprague Dawley rats with spontaneous mammary tumors (five fibroadenomas and one carcinoma) were imaged with three clinical systems (Zonare Z.one, Ultrasonix RP, and Siemens S2000) and one single element laboratory system. Data were acquired from approximately the same region of the tumor with each scanner using independent setups. Scans of a reference phantom and Plexiglas plate were acquired for the clinical and laboratory systems, respectively. The data were analyzed using methods developed by the respective research group. BSC versus frequency plots show agreement in magnitude and trend among the different systems. The BSC estimates overlap each other, showing no more variability between systems than between consecutive imaging planes demonstrating agreement across multiple platforms and varied processing techniques between laboratories. Results support the potential to base diagnoses on QUS parameters. [Work was supported by NIH Grant R01CA111289.]
Contemporary approaches to modeling violin tone, dynamics, and response.
Authors: Denaro F. J.
Published: March 2010

Long-time-average spectral graphs of violin tone reveal some important characteristics of excellent instruments. Included are good dynamic range and frequency response. Significantly there is a marked response in the 194–649 Hz range (high sonority), a lower response for 649–1296 Hz (nasal), good response for 1830–4342 Hz (brilliance), and low response in the 4340–6300 Hz (harsh) [H. Dunnwald, Catgut. Acoust. Soc. J. 1, 1–5 (1991)]. In this talk a working protocol on how to modify the frequency response in each of these areas is explained. Important insights obtained from the burnish/hydrate (B/H) method will be used to illustrate how this can be done in a systematic fashion. The B/H method produces reversible stiffness changes in the plate area of choice. As a result it is possible to evaluate the change in tone and response by listening or by acoustical measurements. If the change is a desired one, it can be made permanent by removing the wood. While the frequency ranges noted above display a degree of interdependence, addressing them independently has led to a general pattern on where the needed plate and corpus modifications should be placed for an excellent violin.
Toward the modeling of harpsichord plucking.
Authors: Perng Chao-Yu J. , Rossing Thomas D. , Brown Marshall J. , Ioup Juliette W.
Published: March 2010

The harpsichord’s plucking action is much less studied than the piano’s hammer striking action. A theoretical model was first proposed [D. H. Griffel, J. Sound Vib. 175, 289–297 (1994)] treating the plectrum as a rigid body or two rigid bodies connected with a torsional spring. This was later investigated experimentally [N. Giordano and J. P. Winans II, J. Sound Vib. 224, 455–473 (1999)] using a capacitive sensor, resulting in a more refined model based on simple one-dimensional beam dynamics. In our work, we employ various string position sensors, and a more detailed plucked string trajectory is captured and analyzed. Also aided by high-speed camera images, studies on the detailed plectrum’s shape of deflection are done. By a more rigorous treatment of elastic beam theory and looking into interactions of the plectrum and string after the initial release, we present a revised model on the plucking mechanism of the harpsichord string that contributes to its characteristic tone quality.
Sonic boom: From bang to puff.
Authors: Plotkin Kenneth J.
Published: March 2010

For almost 40 years commercial supersonic flight over land has been prohibited because of the negative impact of sonic booms. During that time, technology advances have raised the possibility of a muted sonic boom—a sonic “puff”—that could be acceptable over populated areas. This paper reviews the physics of sonic boom generation and propagation, and why booms from conventional aircraft are usually N-waves with unacceptably large shock waves. The low-boom shaping technology that can minimize shocks, thus reducing sonic boom loudness to acceptable levels, is presented. The success of the DARPA/NASA Shaped Sonic Boom Demonstrator in validating shaping theory is discussed. Concepts for attaining practical aircraft configurations, versus ideal optimal shapes, are described.
Low-mass–high-transmission loss portable speech isolation room for very important person protection.
Authors: Rubino Mark
Published: March 2010

This case study examines the design, construction, and testing of a lightweight, easily transportable speech isolation room capable of providing substantial anti-eavesdropping countermeasures for use by high-level government and intelligence agencies as a secure meeting and communications center that can be readily deployed worldwide. The performance criteria requiring a minimum field STC-35 utilizing a modular, scalable mechanical design capable of repeated assembly without the use of tools, a maximum component weight of 2.65 lb/ft2 a 2 in. maximum wall thickness, and the incorporation of active and passive ventilation required the development of a robust, multi-layered composite panel and joining system as well as ancillary components. Using a combination of non-metallic limp mass and rigid metallic barriers separated by decouplers of varying properties in an aluminum shell brake-formed to distort natural resonance, we were able to achieve significant transmission loss (up to 45 dB) in the speech range of frequencies equaling the performance of commercially available products of nearly twice the weight and bulk. Interior room acoustical characteristics were optimized by using modular demountable sound absorptive units.
Pearl Palms concert theater.
Authors: Udolph Steven , Aurther Tera
Published: March 2010

The Pearl Theater was designed and built to meet the demands of both the sophisticated local market and the demanding high-end tourist market in Las Vegas, NV. These markets will quickly dismiss any venue that does not deliver a superior performance, as will the performers that a venue like this must attract in the highly competitive environment, that is, Las Vegas. The Pearl delivers for the audience, the performers, and the owners. Studio X at the Palms is the largest and best-equipped recording facility ever built in Las Vegas. The Pearl Concert Theater is hard wired to the studio to allow artists to conveniently and cost effectively create albums of their live performances in the theater. For the owners to realize a return on their investment in these facilities, the acoustics in the 3294 sq.ft theater had to be impeccable. But the need for a sophisticated sound environment was just the beginning. The aesthetics of the 2400-seat theater were also a major priority. To address both concerns, Dean Roofing & Insulation installed 25000 sq. ft of Tectum 1 in. panels in all of the traffic ways and throughout the theater. The Tectum panels and the seats are the only sound absorbing materials used in this project.
Active noise control of multiple cooling fans.
Authors: Rust Ryan , Blotter Jonathan , Sommerfeldt Scott , Gee Kent
Published: March 2010

Fans are used to dissipate heat from electronic devices to keep the components working properly but create noise as a byproduct. Multiple fans are often needed in computer servers and other types of electronic equipment to adequately cool them. The fan array increases the cooling rate but also increases the noise produced. In addition to the added noise, differences between fans due to manufacturing cause the fans to rotate at different speeds, creating an annoying beat frequency. Feed forward active noise control was studied for an exhaust mounted two fan array using near field error sensors and control speakers. The tonal noise content of the blade passage frequency and the first harmonic was controlled at the error sensors for each fan. The tonal noise content was also reduced in the far field and the beat frequency reduced.
Three-dimensional audio interface: A user’s survey.
Authors: Abouchacra Kim , Sinno Solara , Letowski Tomasz
Published: March 2010

Increasing complexity of military vehicles, high noise levels, and the command and control demands of modern warfare put high physical and mental load on crews operating the vehicles. The need for indirect driving and simultaneous control of various robotic systems demands multisensory interfaces between the crew and the operated systems. One of the promising types of new interfaces is a three-dimensional (3-D) audio interface that presents warning signals and tactical messages at spatial locations associated with the content of the emitted signals or messages. However, not all the information can be displayed through a 3-D interface with needed resolution and sound quality and either too little or too much information can be equally detrimental to the user. This paper is the summary of data obtained through a user’s survey administered to 105 tankers regarding expected functionality of 3-D interfaces in armored vehicles. The results of the survey strongly support the value of the 3-D audio interface for most of the vehicle’s systems and for most operational conditions. The general results and the specific details of the survey will be discussed.
Classroom noise at the Applied Research Laboratory, Penn State.
Authors: Long Marshall
Published: March 2010

Session 3.8: Building Design and Construction for Effective Acoustic Performance Classroom Noise at ARL Penn State by Marshall Long The Applied Research Laboratory at Penn State is a well known center of acoustics education in the United States. When Marshall Long Acoustics was selected to be the acoustical engineer on the new ARL building, we were particularly careful to check every noise source. When we went out on the final inspection, the question arose, “Why is the background noise level NC 42 in a classroom when it should be under 30?” The answer was not so elementary my dear Watson.
Small deviations and big failures in vibration and noise isolation.
Authors: Davis Byron , Bayat Ahmad
Published: March 2010

The difference between design intent and actual implementation is frequently a problem in real constructions. For vibration and noise isolation hardware, seemingly innocuous deviations can result in major deficiencies in performance. From hardware selection to installation and adjustment, vibration isolation systems present significant challenges. In this paper, we offer insight into a broad spectrum of problematic rotating mechanical systems. Numerous categories of vibration-isolation failure are identified, and detailed photographs highlight subtle errors in isolator selection, installation, and adjustment that can lead to poor vibration and noise performance. Before-and-after vibration data are presented to illustrate the effect of poorly isolated rotating machinery. A spectacular example of comprehensive facility-wide failures is given, with ground vibration data from a brownfield site adjacent to an outdated textile plant.
Case study: Computer modeling of exterior mechanical noise from an existing building to develop mitigation for code compliance.
Authors: Wowk Roman , Papadimos Chris
Published: March 2010

This paper presents a case study of how computer modeling was used to develop exterior noise treatments for an existing building. Sound pressure measurements were used to first establish existing ambient noise levels and characterize building noise sources. Following that, a computer model of the building and surrounding area was constructed using commercially available environmental noise modeling software. Noise sources were modeled using sound power spectra from equipment manufacturers or approximated from measured sound pressure levels. The predicted ambient noise levels compared favorably to the measured data, thus validating the accuracy of the model. Once this baseline condition was established, a new building proposed between the existing building and the residences was added in the model to predict how it would function as a barrier to reduced noise at the residences. To develop additional noise treatments necessary for code compliance, the model was then used to determine the contribution of each piece of equipment at key receiver locations. Specific equipment could be targeted when considering noise treatments and noise exposure maps could quickly be produced for a combination of scenarios to aid in finding the most cost-effective solution.
Determining sound quality judgments for metric development.
Authors: Fiebig André , Genuit Klaus
Published: March 2010

The sound quality of various technical products has become important for manufacturers. It is interpreted as among the most relevant factors regarding perceived product quality and is important in gaining market advantage. Usually, the purpose of sound quality studies is to derive a relationship between the subjective attributes and physical properties of sound. But how can valuable and meaningful subjective data be obtained? Identifying the most important psycho-physical quantities reflecting human responses to specific evaluation criteria depends on the applied method and the test design. Weighting factors for individual parameters in a combined metric depend strongly on the sounds used, the test environment, and the evaluation task. This paper will contrast the strengths and weaknesses of different methods, and discuss their level of inaccuracy in the intended application. The possibility of combining methods could be a step forward to achieve more grounded results and to enhance the explanatory power of developed metrics. Results of a few case studies will be presented, and options for combining different methods will be discussed.
Effect of damping on noise and vibration response of tubes.
Authors: Patil Avinash
Published: March 2010

Noise and vibration response of cylindrical tubes is critical in many applications such as automotive intake and exhaust manifolds, appliance tubes, and fluid flow pipes. One of the approaches of controlling noise and vibration response is to introduce damping in the tube. An investigation of tubes with dimensions similar to that of intake manifold tube of a large truck is presented in this paper. Two tubes were investigated, viz., monolithic steel tube and laminated steel tube. Dispersion relation for the tube was analyzed. Effects of structural waves propagating in axial and circumferential directions were studied for their coupling with acoustic space. Effects of ring frequency of the cylinder and critical frequency of the material were analyzed. An experimental investigation was conducted for the tubes. Experimental results are explained with the help of theoretical analysis of the tube.
Rail and wheel vibration absorber performance testing.
Authors: Nelson James Tuman
Published: March 2010

Rail and wheel dynamic vibration absorbers have been proposed as noise reduction measures for rail transit systems in Europe and the United States. These absorbers are essentially tuned spring-mass systems that add damping to the rail or wheel, and can effectively control wheel squeal. Their noise reduction effectiveness for rolling noise and rail corrugation noise is less clear. The extensive test results of under-car and wayside noise reductions are presented and discussed for wheel vibration absorbers at the San Francisco Bay Area Rapid Transit (BART) system for operations on resilient direct fixation fasteners. These results are compared with test results obtained under TCRP Project C3 at the Portland Tri-Met light rail system for both rail and wheel vibration absorbers. The reduction in pinned-pinned mode rail vibration by application of rail vibration absorbers on ballast-and-tie track at Tri-Met is discussed.
Predictability of field airborne noise isolation from laboratory testing.
Authors: LoVerde John , Dong Wayland
Published: March 2010

The relationship between laboratory and field noise isolation tests of nominally identical assemblies is a longstanding question in acoustics [LoVerde and Dong, J. Acoust. Soc Am. 122, 2955 (2007)]. Many building codes allow field airborne noise isolation ratings (ASTC, NIC, or NNIC) to be five points lower than the corresponding laboratory rating (STC), but the origin of this relationship is not documented thoroughly in the literature. Different wood framed floor/ceiling systems were tested multiple times in the laboratory to determine performance prior to implementation in the field. Field testing was performed in a variety of completed buildings to determine the actual acoustical performance of the assemblies that were installed. The results of this testing for airborne sound isolation is presented. The authors will present analysis of the predictability of field test results based on laboratory test and the apparent translation from laboratory to field testing.
Liftoff acoustic environment of the sounding rocket ATK Launch Vehicle (ALV-X1): Prediction versus measurement.
Authors: Houston J. , Counter Douglas , Kenny R. Jeremy , Murphy John
Published: March 2010

Launched from the Mid-Atlantic Regional Spaceport (MARS) Pad 01B on August 22, 2008, the ATK Launch Vehicle (ALV-X1) provided an opportunity to measure liftoff acoustic noise data. Predicted liftoff acoustic environments were developed by both NASA MSFC and ATK engineers. ATK engineers developed predictions for use in determining vibro-acoustic loads using the method described in the monograph NASA SP-8072. The MSFC ALV-X1 liftoff acoustic prediction was made with the Vehicle Acoustic Environment Prediction Program (VAEPP). The VAEPP and SP-8072 methods predict acoustic pressures of rocket systems generally scaled to existing rocket motor data based upon designed motor or engine characteristics. The predicted acoustic pressures are sound-pressure spectra at specific positions on the vehicle. This paper presents the measured liftoff acoustics on the vehicle and tower. Additionally, the ALV-X1 liftoff data can be scaled to define liftoff environments for the NASA Constellation program Ares vehicles.