bluuebunny/crossref_metadata_2025 huggingface dataset:
Descriptive acoustics of music and speech
Authors: Strong William J.
Published: October 2013

A brief background will be given of ‘‘Descriptive Acoustics of Music and Speech,’’ an introductory course taught at Brigham Young University for the past 40 years. Several conceptual and physical models used in the course will be described. Some phenomena observed in music and speech will be explained in terms of the models. Diagrams, sound samples, and video clips will be used to illustrate the phenomena and their explanation.
Noise and its hot topics
Authors: Schulte-Fortkamp Brigitte
Published: October 2013

Noise is an increasing challenge; the pollution of the environment comprises a multitude of risks. Fortunately, there is also great effort for assessment and evaluation that touches and also includes socio-cultural, psychological, architectural, ecological, and health fields. To sufficiently consider local and regional conditions there is an ongoing process within TC Noise to understand soundscapes as a new tool for the measurement, analysis, and design of environmental and community noise that applies the knowledge of both science and community experts. The process for standardization is under initiative. Classroom acoustics, which achieved great success, is now on the way to enforce its widespread acceptance supported by members from TC Noise, Architectural Acoustics, Speech Communication, ASA-Committee on Standards, and others. Work on improved noise control continues and places emphasis on noise in hospitals. The importance of noise in health care suggests that the problem of hospital noise is universal, and that noise control techniques might also be expected to be applicable broadly. Taking into account the fact that the life quality of millions of people is severely impaired by noise from different sources, we will keep moving.
Vision influences judgments of acoustic duration
Authors: Schutz Michael , Kubovy Michael
Published: October 2013

We video-recorded isolated marimba notes performed by a world-renowned percussionist attempting to produce long (L) and short (S) notes. We generated audio-visual stimuli by crossing the video components of these notes. Subjects rated the duration of sounds presented in the audio-alone (A), and in the audio-visual (AV) condition (in the latter, they were to rely only on auditory information). In the A condition the S and L sounds were rated to be equal. In the AV condition, visual information affected ratings, but auditory information did not. In a second experiment, to undermine a response-bias account of these findings, we introduced a temporal offset between the auditory and visual information. When the visual information preceded the auditory, vision influenced auditory judgments, but when the visual information lagged it did not. This tolerance for visual lead may reflect an ecology in which optical information about an event precedes the acoustic information about it. Together, these studies demonstrate a novel visual influence on auditory judgments of duration through the integration of sensory information.
Quantifying speech rhythm deficits in dysarthria
Authors: Liss Julie , Spitzer Stephanie , Lansford Kaitlin , Choe Yu-kyong , Kennerley Kathryn , Mattys Sven , White Laurence , Caviness John
Published: October 2013

Disturbances in speech rhythm are common in dysarthria, and deficit patterns vary among dysarthria subtypes. Attempts to quantify differences in disordered rhythm patterns have met with limited success. Here, we attempt to differentiate various forms of dysarthria using metrics designed to quantify linguistic rhythm on a stress-timed versus syllable-timed continuum. Speakers with hypokinetic, ataxic, hyperkinetic, or mixed flaccid-spastic dysarthria read sentences. Rhythm metrics were calculated for these utterances based on vocalic and consonantal interval durations. Differences among groups were discovered for %V (percentage of utterance duration comprised of vocalic intervals), VarcoV (rate-normalized standard deviation of vocalic interval durations), and nPVI-V (normalized pairwise variability index for vocalic intervals). Differences were independent of variable speaking rates among groups. All dysarthric groups produced rhythm patterns less stress-timed than the control American English speakers, with lower VarcoV and nPVI-V and higher %V. Those with flaccid-spastic dysarthria secondary to amyotrophic lateral sclerosis exhibited a syllable-timed pattern more extreme than even control Spanish speakers, indicating minimal differentiation of stressed and unstressed syllables. These results show that the various types of rhythmic disturbance accompanying dysarthria can be effectively described and distinguished within a stress-/syllable-timed continuum and relative to healthy speech.
An improved distance metric for disordered speech evaluation
Authors: Singh Savyasachi , Harris John , Shrivastav Rahul , Sapienza Christine
Published: October 2013

Assessment of the quality of disordered speech due to dysarthria, laryngeal diseases, stroke or other impairments is important for feedback to keep track of the development of patients pathology. Methods based on perceptual evaluation of speech quality are accurate and robust but expensive and time consuming. This study focuses on the development of a distance metric for disordered speech quality assessment based on signal processing techniques which is inexpensive, fast, affordable and easy to use. Previous efforts from our group have shown this can be achieved with short-term Mel frequency cepstral coefficients (MFCC) along with dynamic time warping (DTW) and Itakura-Saito distortion measures. Disordered speech is characterized by several long time signal variations such as increase of hoarseness in voice, speaking rate variability, word closure variability, presence of high frequency noise components, large pitch period and peak amplitude variations. An improved distortion metric is developed which accounts for these characteristics by augmenting the feature set with measures such as jitter, shimmer, amplitude perturbation quotient (APQ), pitch perturbation quotient (PPQ), harmonics to noise ratio (HNR) and uses DTW for alignment. Initial results with a speech verification database are promising while the full system development is underway.
Consonant-vowel (CV) and vowel-consonant (VC) transitions in the speech of persons with dysarthria and healthy controls
Authors: Weismer Gary , Kuo Christina , Chung Yun-Ching
Published: October 2013

Previous work has shown that speakers with dysarthria have shallower-than-normal slopes for second formant transitions in diphthongs and semivowels. Little is known, however, about transition characteristics in dysarthria for CV and VC transitions. In the present work, stop-vowel, fricative-vowel, and nasal-vowel formant transitions (and VC counterparts) were measured from words in a reading passage produced by 25 controls, 22 patients with Parkinson disease, and 15 patients with ALS. Measures were made over a 50-ms interval extending from the first glottal pulse of the vowel (in CV syllables) or back from the final glottal pulse in VC syllables. Transition extents over this interval were measured and slopes derived. Distributional analyses suggest that slope differences between control speakers and speakers with dysarthria are subtle, but show a slight tendency for greater absolute values for the control speakers. This is consistent in kind with work on diphthongs and semivowels, but the subtlety of the effect is quite different. The apparent greater resistance of the CV and VC transitions to the effects of dysarthria, compared to effects on other kinds of transitional events, is discussed within the framework of contemporary speech production theory. [Work supported by NIH Award DC 03723.]
Evaluating the effect of subthalamic deep brain stimulation on vocal function in Parkinson’s disease
Authors: Wang Emily , Jiang Jack , Verhagen Metman Leo , Bakay Roy , Bernard Bryan
Published: October 2013

The study reports the effect of subthalamic deep brain stimulation (STN DBS) on vocal function in Parkinson’s disease (PD). Specifically, the effect was evaluated in relation to the vibratory characteristics of the vocal folds during sustained vowel phonation using two different methods: one measures jitter and shimmer, while the other measures the correlation dimension D2, a nonlinear dynamic analysis. Twenty right-handed individuals with advanced PD and dysarthria underwent unilateral STN DBS. Ten were operated on the right hemisphere and ten on the left hemisphere. The side receiving STN DBS had more affected motor function. Speech was evaluated before surgery and three-to-six months after surgery with stimulator-off and with stimulator-on; all were off anti-Parkinsonian medication for 12 h before evaluation. Evaluators and subjects were blinded to the subjects stimulator status at the postsurgery evaluations. Nonspeech motor performance was assessed with UPDRS-III. Each subject produced six maximally sustained ‘‘ah’’ phonations (MSVPs) at his/her habitual loudness level. Two-second samples extracted from the MSVPs were used for both analyses. In addition, the maximum vocal intensity, duration, mean F0, and cycle-to-cycle F0 variation were also obtained. The results were discussed with regard to Chaos theory and the phonation characteristics in PD.
New features in VTAR: A Matlab-based computer program for vocal tract acoustic modeling
Authors: Espy-Wilson Carol , Zhou Xinhui , Tiede Mark , Boyce Suzanne
Published: October 2013

VTAR, a Matlab-based computer program for vocal tract acoustic response calculation [Zhou et al., J. Acoust. Soc. Am. 115(5), 2543 (2004)], has been used in both research and teaching. In its latest version, several new features are included, which are speech sound synthesis with source model options, formant sensitivity function calculation, susceptance plots calculation useful particularly for nasalized vowel analysis, and addition of a new set of area function data for liquid sounds extracted from MR (magnetic resonance) images. These new features along with the user-friendly interface significantly enhance the usability of VTAR for both teaching and research purposes. [Work supported by NIH Grant 1 R01 DC05250-01.]
Structural analysis of a three-layered vocal fold model
Authors: Cook Douglas , Nauman Eric , Mongeau Luc
Published: October 2013

Although many detailed fluid-structure interaction models of human phonation have been created, structural analysis of the vocal fold structure is uncommon. As a result, the vocal fold structure is not well understood. Structural analysis provides useful information for the creation of efficient fluid-structure interaction and reduced order models. To this end, a detailed model of the human vocal fold was created, and modal analysis was used to determine the model’s sensitivity to boundary conditions, geometric parameters, and material properties.
Intraglottal pressures in a static physical hemilarynx model
Authors: DeWitt Ken J. , Bo Yang , Thapa Pushkal , Fulcher Lewis P. , Scherer Ronald C.
Published: October 2013

Intraglottal air pressures during oscillation of a single vocal fold against an immobile opposing structure are of interest to surgery after unilateral vocal fold removal and the validity of pressure data in hemi-laryngeal bench studies. Intraglottal pressures and flows within a static hemilarynx were studied using Plexiglas model M5 with removable vocal folds and FLUENT, a commercial code using the control-volume technique. For a minimal diameter of 0.04 cm, an axial glottal length of 0.3 cm, and a vertical static opposing wall, data were collected for converging and diverging angles of 5, 10, and 20 (and 0) deg. Pressure distributions were obtained for transglottal pressures of 3 to 40 cm water. For divergent, zero, and smaller converging angles within the physical model, greater intraglottal velocities could be coaxed to favor one side or the other and were typically stable. The side of faster flow for divergent angles had lower pressure in the downstream third of the glottis ranging from approximately 5% to 20% of the transglottal pressure, which would produce asymmetrical forces acting on the opposing vocal folds. FLUENT results are in good agreement with the measured pressures. [Work supported by NIH R01DC03577.]
Aerodynamics at glottal exit using particle image velocimetry method in a canine larynx
Authors: Khosla Sid , Murugappan Shanmugam , Lacham Raju R. R. , Gutmark Ephraim J.
Published: October 2013

There are several excellent computational and mechanical models that describe the flow fields exiting the glottis during phonation. However, these models need to be validated and possibly refined in the canine larynx. Experimental characterization of flow at the glottal exit has been limited to hot-wire anemometry measurements made no closer to the glottal exit than 1 cm; these measurements have also been limited to magnitude and have not included flow direction. Using the particle image velocimetry method, velocity fields have successfully been measured in the excised canine larynx during phonation within the first cm above the glottal exit. Previous papers have discussed the methodology and qualitatively described the spatial and temporal location of the vortices. In this paper, quantitative characteristics of the velocity field in the first centimeter above the glottal exit in an excised canine larynx model without a vocal tract will be shown; these characteristics elucidate how the jet transforms as a function of space and phase. Comparisons to physical and computational models will also be described and further work will be discussed. [Work supported by NIH Grants K08DCC005421 and R01DC003577.]
The use of directional and binaural microphones for troubleshooting room acoustic problems
Authors: Mapp Peter
Published: October 2013

A common problem encountered when troubleshooting room acoustic issues (apart from the room exhibiting an overly long reverberation time or inadequate sound insulation) is the generation of late arriving reflections and echoes. The paper describes a number of techniques using both directional and binaural microphones as well as microphone array techniques for determining the direction, timing, and relative strength of such reflections. It is shown that in many situations, apparently highly directional microphones such as hypercardioid or rifle types, do not offer sufficient directional discrimination to be of much practical use. It is also shown that the inconsistent off axis frequency response of many such microphones can also lead to misleading analyses. Parabolic dish reflector microphones are shown to offer superior performance as do some microphone array techniques. It is shown that binaural measurements can also be a useful approach particularly with regard to assessing the subjective affect of reflections. The results of some early research into a novel extension to the Speech Transmission Index (STI) for assisting with acoustic trouble shooting will also be presented.
Lessons learned from room acoustics design and investigation (especially from using EASE room acoustics software) in our consulting practice
Authors: Bridger Joseph , Stewart Noral , Farbo Aaron
Published: October 2013

Experiences troubleshooting during the design of new buildings and investigation of existing acoustical problems in existing buildings, including churches, dining spaces auditoria, public meeting spaces, offices, and rehearsal spaces. Lessons learned and experiences with tools, such as EASE room acoustics software. Theoretical concepts to consider in designing box shaped rooms, cafeterias, rehearsal spaces, and churches. Tools and methods to consider in acoustical investigations.
Case studies of troubleshooting room acoustics problems using critical listening, field measurements, and computer models
Authors: Siebein Gary W. , Lilkendey Robert M. , Paek Hyun , Skorski Edwin S.
Published: October 2013

Combinations of critical listening, field measurements of impulse responses and their associated metrics, and computer model studies were used in four projects to troubleshoot acoustical problems perceived by users and to study potential design solutions. Case study 1 is a 56-person firing range at a law enforcement training center nicknamed the Thunder Dome because of the excessive build-up of reflected and focused sound in the room. Case study 2 involved the diagnosis and correction of excessive loudness in a band practice room where instructors were threatening legal actions for hearing compensation claims against the school board. Case study 3 is a large multi-purpose performing arts center that suffered from many architectural acoustics and sound system design defects. Case study 4 involved the diagnosis and correction of sound focusing in an exclusive restaurant at a major resort that resulted from very subtle wall and ceiling shapes. The case studies illustrate the range of issues that can be studied with computer models and field measurements, as well as understanding the limitations of the techniques at the present time.
Coded excitation and subband processing for blood velocity estmation in medical ultrasound
Authors: Gran Fredrik , Jensen Jorgen Arendt , Udesen Jesper , Nielsen Michael Bachmann
Published: October 2013

This paper investigates the use of broadband coded excitation and subband processing for blood velocity estimation in medical ultrasound. In conventional blood velocity estimation a long (narrow-band) pulse is emitted and the blood velocity is estimated using an auto-correlation based approach. However, the axial resolution of the narrow-band pulse is too poor for brightness-mode (B-mode) imaging. Therefore, a separate transmission sequence is used for updating the B-mode image, which lowers the overall frame-rate of the system. By using broad-band excitation signals, the backscattered received signal can be divided into a number of narrow frequency bands. The blood velocity can be estimated in each of the bands and the velocity estimates can be averaged to form an improved estimate. Furthermore, since the excitation signal is broadband, no secondary B-mode sequence is required, and the frame rate can be increased. To increase the SNR for the broad-band excitation waveforms, coding is proposed. Three different coding methods are investigated: nonlinear frequency modulation, complementary (Golay) codes, and Barker codes. Code design is described for the three different methods as well as different ways of pulse compression for restoring axial resolution. The different methods were studied using an experimental ultrasound scanner and a circulating flow rig.
Improved scatterer size estimation from ultrasound backscatter using coded excitation and pulse compression
Authors: Oelze Michael L. , Kanzler Steven
Published: October 2013

Scatterer size estimation from ultrasound backscatter has been used to improve the detection and classification of cancer. Estimates of scatterer size from tissues come from ultrasound backscattered signals that often have low signal-to-noise ratio (SNR). Coded excitation was explored as a means to increase the SNR of signals used in scatterer size estimation. The normalized backscatter coefficient was measured from tissue mimicking phantoms containing glass beads. The diameters of the glass beads were estimated by fitting the normalized backscatter coefficient to models for scattering from spheres [J. Acoust. Soc. Am. 23, 405–418 (1951)]. Two weakly-focused, single-element transducers (f0=5 MHz, −6 dB BW=4.2 MHz, f/3, and f0=10 MHz, −6 dB BW=9.1 MHz, f/4) were used in the measurements. For coded excitation, a linear FM chirp with a time bandwidth product of 40 was used. Three phantoms with average glass bead diameters of 30, 45, and 82 μm were scanned. Preliminary results indicated that estimate bias was reduced versus penetration depth for the coded excitation compared to conventional pulsing. In addition, estimate variance using the coded excitation technique was reduced because the SNR was increased. [Work supported by start-up funds from the University of Illinois at Urbana-Champaign.]
An ultrasonic imaging speckle suppression technique by means of frequency compounding and coded excitation
Authors: Sanchez Jose R. , Oelze Michael L.
Published: October 2013

A method for improving the contrast resolution of an ultrasonic B-mode image is proposed by combining the speckle reduction technique of frequency compounding and the pulse compression technique of resolution enhancement compression (REC). Frequency compounding is known to suppress speckle in B-mode images to provide improvements in image quality and contrast resolution, but at the expense of deteriorating the axial resolution. The REC technique is used to enhance the bandwidth of the ultrasonic imaging system by using convolution equivalence. This enhanced bandwidth translates into improvements in axial resolution of the ultrasonic imaging system. Therefore, these improvements in axial resolution are exploited to improve contrast resolution. Improvements are quantified by using contrast-to-noise ratio (CNR) metric in simulations and experiments. In simulations, a phantom with a hyperechoic target was imaged by utilizing a single element transducer with a center frequency of 2.25 MHz. In experimental measurements, a single-element transducer (f/3) with a center frequency of 2.25 MHz was used to image ±3- and ±6-dB cysts in an ATS 539 multipurpose tissue-mimicking phantom. Preliminary simulation and experimental results indicated that the CNR could be improved by up to 25% and 60%, respectively, without sacrificing axial resolution compared to conventional pulsing methods.
An integrated optical microphone test-bed for acoustic measurements
Authors: Garcia Caesar T. , Hall Neal A. , Degertekin F. Levent , Bicen Baris , Jeelani Kamran , Qureshi M. Shakeel
Published: October 2013

A diffraction-based optical detection method for microphone applications has been demonstrated previously [Hall et al., J. Acoust. Soc. Am. 118, 3000–3009 (2005)]. This method, coupled with proper integration techniques can produce precision measurement microphones with 24 dBA noise levels and suitable bandwidths. Thus far, these characterization studies have been performed using experimental setups, which would disturb the acoustic field due to size and non-symmetric features. In these regards, previous optical microphone test beds have been inadequate experimental platforms. This has motivated the development of a more robust integrated instrumentation microphone package for future testing and characterization. In order to meet the size restrictions for such an optical microphone platform, vertical cavity surface emitting lasers are used as light sources and small photodiode arrays are used to detect intensity variations in refracted orders of the optical detection method. The overall dimensions and shape of the package are comparable to commercially available half-inch calibration microphones and impose minimal sound field disturbance. The design is adapted to allow simple replacement and remounting for multiple microphone testing including biomimetic directional microphones [Miles et al., J. Acoust. Soc. Am. 98, 3059–3070 (1995)]. [Work partially supported by NIH Grant 5R01DC005762-03 and the Catalyst Foundation.]
Effectiveness of Physlet computer animations for enhancing student learning of acoustic principles in a course for non-science majors
Authors: Piacsek Andrew A. , Wright Ian
Published: October 2013

A set of interactive computer animations of acoustic phenomena was created using the Java-based PHYSics appLETS (or physlets) developed at Davidson College [Christian and Belloni, 2001]. These animations allow the user to adjust certain parameters of a modeled system and view—in real time—the corresponding change in the physical behavior of the system. Because the animations are accessed via the web and can run on any computer (using Java), students can work with them in many different settings. The goal is to help students with limited math skills who enroll in PHYS103 ‘‘Physics of Musical Sound’’ at Central Washington University develop an intuitive understanding of basic acoustic phenomena and to assist them in applying quantitative reasoning to predict the behavior of musical systems. These newly-created acoustics and vibration physlets will be used for the first time during the Spring term, 2007, in the PHYS103 course taught by the author. Students will be given a quiz before and after working with the physlets on various topics to assess the effectiveness of this pedagogical tool.
Using technology to enable people of all abilities to explore music
Authors: Disley Alastair C. , Howard David M. , Hunt Andrew D.
Published: October 2013

MIDI Creator is a commercially available programable device that converts sensor inputs to MIDI data, which can then directly trigger sound or be used as controls for more complex environments. A variety of sensors are available, including pressure-sensitive floor pads and ultrasonic beam controllers. The authors present two applications of this technology, which illustrate the system’s ability to be used in music education and music therapy environments. In the first instance, two rows of floor pads were used as controls for a game projected onto the floor. The default game was a co-operative ping-pong variant, in which users were encouraged to work together to achieve the highest number of volleys. Other options included musical games, where users could co-operate to produce harmonies. All ages and abilities, including wheelchair users, were able to take part on an equal basis. In the second instance, a simple potentiometer was explored as an input device. School children rotating the potentiometer caused the MIDI Creator to play a scale and light lamps corresponding to the notes being played. The children then decided which notes lit which lamps. Other uses of MIDI Creator in the areas of music education and music therapy are summarized.
Turbulence flow modeling using combined compressable Euler and molecular dynamic simulation (MDS) methods
Authors: Bader Rolf
Published: October 2013

Typical flows found with musical instruments as well as turbulent behavior are modeled. Here the problem of using many elements to model the system precisely resulting in very long simulation time is avoided using molecular dynamic simulation techniques, where the flow is represented by moving particles that can be at any position in space and so act as an alternative to small grid lengths. On the other hand, the coupling between the flow and the acoustic wave caused by oscillations of that flow is modeled using the compressable Euler model. Here, the equation of continuation is used for modeling a time dependency of the pressure and is thus capable of combining the models. Both models are presented on their own and also in several possible combinations. The flow and pressure distribution behavior of possible couplings between these methods is then discussed in terms of comparison with experimental data, modeling stability, and modeling speed.
Acoustic monitoring and resource management in national parks
Authors: Fristrup Kurt
Published: October 2013

The Organic Act of 1917 and other legal mandates and authorities require the NPS to protect and restore park resources. Acoustic monitoring has been conducted in 43 park units. These studies have documented sound levels (in 1/3 octave bands) and identified sources of noise. Analyses show that backcountry sites can be extraordinarily quiet, but noise events occur at all locations. It is clear that noise presents two threats to park resources: chronic degradation of listening opportunities as well as acute effects from prominent events. The NPS is developing metrics that assess the extent to which noise degrades the opportunities for visitors to experience the sounds intrinsic to the park unit. These metrics also apply to the degradation of aural awareness for wildlife, which can affect foraging success, predator avoidance, and acoustic communication.
Modeling noise and visitor use in national parks
Authors: Plotkin Kenneth J. , Lawson Steven R. , Fristrup Kurt M.
Published: October 2013

The natural soundscape in National Parks is degraded by the intrusion of human-made noises. One usually thinks of the intrusive sounds as those from mechanical devices: aircraft, snowmobiles, off-highway vehicles, tour buses, generators, etc. Noise Model Simulation (NMSim) developed for the Park Service was designed to address those sources. There is, however, often a significant nonmechanical human noise source: the humans themselves. Visitors traveling in groups tend to talk to each other, and that speech can be an intrusive noise source. Newman et al. conducted a listening exercise in Muir Woods National Monument in 2005 to assess the nature of these human sounds. In the fall of 2006 Lawson et al. conducted noise and trail use monitoring in the Great Smoky Mountains National Park, which quantified visitor-generated sound levels and provided input to trail use modeling. Those data provide inputs to NMSim, so that the exposure of visitors to visitor noise and the impact of visitor noise on the soundscape can be quantified. The Smokies study will lead to a general merger of noise and trail use modeling, so there will be tools for this aspect of soundscape modeling and preservation in National Parks.
Protecting natural soundscapes with an adequate margin of safety
Authors: Horonjeff Richard , Anderson Grant
Published: October 2013

The natural ambient sound environment in park-like settings not only provides a masker for inappropriate sounds, but also affords different acoustic experiences to the park visitor due to its dynamic nature. At a single location, for example, the absence of wind and water movement may offer periodic opportunities to experience an environment completely devoid of audible sound. At the same location wind blowing gently through nearby conifers may offer a feeling of tranquility. In late spring the sound of water in a nearby stream may provide yet another experience. Each circumstance generates a different ambient sound environment, both for soundscape enjoyment as well as masking inappropriate sources (usually human activity). This dual role creates challenges in soundscape management and planning and makes difficult the use of a single ambient descriptor to protect a sites multiple non-concurrent soundscape resources. This paper examines soundscape impairment from a damage risk perspective by assuming independent, quasi-random arrivals of various soundscapes and human activity. Actual data from three western U.S. parks are used to establish reasonable parameter values for the analysis. The paper develops impairment risk with an adequate margin of safety in line with philosophies of the EPA Levels Document of 1974.
Cleaning up 20th century acoustical trash from national parks: 10 ways to quiet our parks
Authors: Blomberg Leslie D.
Published: October 2013

The history of noise in the 20th Century follows a consistent pattern, first the invention of new noise sources, then the growth in use of those sources, and finally the spread of those noises into previously quiet areas. Our National Parks have experienced that same pattern of invention, growth, and spread. Moreover, those previously quiet areas that succumbed to 20th Century noises often included our Parks and wildlands. Since most of the noises degrading National Parks are 20th Century inventions, this paper will examine the historical context of todays park noise, with an emphasis on developing policy options to quiet our National Parks.
A low-complexity environmental noise monitoring system for unattended operation in remote locations
Authors: Collier Robert D. , Kaliski Kenneth
Published: October 2013

There is a need to measure environmental noise in remote locations such as national parks over extended periods of time with a simple, readily deployed, robust, unattended data acquisition system. The original Dartmouth College prototype system was demonstrated in 2001 [Kaliski et al., Proceedings NOISE-CON 2001, October 2001]. The improved Dartmouth system is described in a patent awarded to Dartmouth College in August 2006. The system conforms to ANSI/IEC Type I and Type II standards. It samples, processes, and stores 1-s A- and C-weighted equivalent sound level (Leq) values over a period of about 2 weeks. In addition, maximum, minimum, and statistical percentile values are stored in nonvolatile memory. The instrument is powered by a rechargeable battery backed up by a solar power converter. A communication interface provides for remote control. Separate software is provided to display statistical information and detection and classification clues based on user-selected time period events. The capabilities of the improved Dartmouth system are demonstrated in a selected measurement program.
Characterizing natural soundscapes and understanding human response to human-caused noise in a Hong Kong country park
Authors: Lam Kin-che , Chau Kwai-cheong , Marafa Lawal M.
Published: October 2013

A study was undertaken in a country park of Hong Kong to characterize the natural soundscapes and determine the affective response of visitors to natural and human-caused sounds. Located on the eastern extremity of Hong Kong, the country park is easily accessible and characterized by sandy beaches, rocky shores, rugged slopes, and wooded ravines nested among silent hills and mountains. The country park is exposed to varying levels of transportation noise (motor vehicle, aircraft) and visitor-caused noise. The soundscapes of a variety of natural landscapes were characterized by sound walks and acoustical and psycho-acoustical analysis of 15-min and 24-h sound recordings. Interviews with the country park visitors revealed that they preferred soundscapes with natural and joyful attributes. A questionnaire survey was undertaken in several landscape-soundscape settings with different exposure levels of human-caused noise. The results show that while the visitors were slightly bothered by extraneous noise, the degree of annoyance was significantly determined by the natural setting, the background soundscape, and the type of activities engaged in. The findings provide an empirical basis to formulate management strategies of natural soundscapes and contribute to a growing body of research on the potential impacts of human-caused sound in country parks.
Recent developments in the use of structural actuators for decentralized active control
Authors: Elliott Stephen , Gardonio Paolo , Baumann Oliver , Aoki Yoko
Published: October 2013

With an array of ideal, dual, collocated actuators and sensors, decentralized feedback controllers can not only be unconditionally stable, but their performance in reducing vibration and, hence, radiated sound, can approach that of a centralized LQG controller [W. P. Engles et al., JASA 119, 1487–1495 (2005)]. They also have a modular architecture that scales well, even for very large structures. This paper discusses some of the problems that arise in practice when proof-mass or piezoelectric transducers are used instead of ideal force or moment-pair actuators in such decentralized controllers. Proof-mass actuators are attractive when generating significant forces, but their natural frequency must be well below the first structural resonance frequency for stable operation. Even when this is achieved, impulsive forces due to the actuators hitting their end-stops have recently been shown to potentially be an additional source of instability. Piezoceramic actuators can give significant control in thinner structures, but as well as controlling out-of-plane vibration, they also create in-plane motion in the structure that can couple into closely located strain sensors causing instability in feedback controllers. Novel arrangements of such transducers will be described in which the effect of in-plane coupling is minimized, thus significantly improving their performance.
Active noise control for double glazing
Authors: Carme Christian
Published: October 2013

Implementation of ANC on double glazing windows has been investigated through controlling the volume of the air gap between the two window panes. In past work, the major problem was the location (generally in the middle of the glass plane) and/or efficiency of the transducer generating the counter noise. A new transducer (called strip-transducer) overcomes this problem by locating the loudspeaker system in the window frame. The transducer consists of a beam like rigid membrane (less than 20 mm width and 500 mm length) attached to a longitudinal voice coil suspended in the magnetic field generated by a set of magnets located in a metallic U-shaped profile. These strip-transducers are driven by a local ANC control loop, the reference sensor being either a microphone or an accelerometer located in the emitting side and the error microphone being located on the receiving side. The control loop algorithm is based on TechnoFirsts patented cloverleaf filter, allowing a faster response than traditional X-LMS algorithms. The transducer design uses the concept of tuned membrane resonator (TMR) to reduce the drive energy needed. A prototype using this new concept is under experimentation and has shown very encouraging results.
Angle of incidence seismic/acoustic ratios during wet and dry ground conditions
Authors: McNeill Chris A. , Sabatier James M.
Published: October 2013

Modeling the out-of-plane seismic-to-acoustic (S/A) transfer function shows frequency and angular dependences. The amplitude, frequency, and angle of incidence analysis shows rapid shifts in the frequency locations of the transfer function maxima as the angle of incidence of the sound source becomes greater than critical angles for the deeper soil layers. Outdoor measurements of the transfer function were conducted to verify this critical angle effect. These measurements used a suspended loudspeaker as a source and vertical and horizontal component geophones as receivers to measure the angular dependence of the in- and out-plane S/A coupling ratio during wet ground conditions. The calculated S/A ratio using sound speeds and layer depth collected during dry conditions revealed critical angle effects at the test site that are similar to those in the literature. However, the S/A ratio measurements during wet conditions did not exhibit such effects. Modeling the ground as a low speed wet soil layer over a fast bottom with water table sound speeds agrees with the measured wet ground transfer function data. The wet ground condition properties will be verified and S/A ratio measurements will be made during the dry ground conditions to verify these hypotheses.
Perceptual and acoustic correlates of perceptual structures of environmental sounds
Authors: Bonebright Terri , Nees Michael
Published: October 2013

The present study was designed to provide insight into the perceptual structure of everyday sounds and how that structure relates to the external acoustic signal. Two large stimulus sets of 74 sounds each were used to gather sorting data, attribute ratings, and basic acoustic measurements for analysis using multidimensional scaling solutions (MDS). Correlations between and among the acoustic measurements and attribute ratings were as expected. The resulting MDS solutions with regressed vectors for attribute ratings and acoustic measurements revealed a well-defined three-dimensional perceptual structure for both stimulus sets. Similarities and differences in the scaling solutions will be discussed. Information about perceptual structure from such studies can be used by researchers to increase basic knowledge about how people perceive the relationships among everyday sounds as well as by designers of virtual reality environments to assist in developing algorithms for realistic synthesized sounds.
Changes in acoustic characteristics of /r/ following production training using electropalatography (EPG)
Authors: Schmidt Anna
Published: October 2013

Visual feedback using electropalatography (EPG) is an effective method for changing production of speech sounds in children. Differences in tongue placement and general acceptability of production have been demonstrated with EPG training for tongue to palate contact. Little is known, however, about changes in the spectral characteristics of speech sounds following training. The current study examined pre and post EPG patterns for /r/ in prevocalic, intervocalic, and postvocalic positions in sentences with five weeks of intensive EPG training. In particular, spectral characteristics of /r/ were examined for differences pre and post treatment. Subjects were four children (aged 9–10). These children exhibited distorted /r/ despite several years of traditional speech therapy but learned to produce perceptually acceptable /r/ with EPG. Spectral characteristics for /r/ productions in the same sentences by four typically developing children were used for comparison. Differences will be discussed in terms of acoustic characteristics as well as changes in tongue position.
Rate normalization of closure duration influences on an assimilation context effect
Authors: Gow David , Winchell-Manning Claire
Published: October 2013

Variation in speech rate influences the structure and distribution of phonetic cues in a variety of ways. For example, a large body of work demonstrates that the rate of speech and nonspeech precursors influences the interpretation of temporal cues associated with phoneme categorization. Changes in speaking rate also influence the absolute size of the temporal window over which multiple cues to the identity of a segment may be distributed. This has potentially significant implications for the perception of assimilated speech in which feature cues from adjacent segments interact to produce bidirectional context effects. These implications were explored in a series of mousetracking experiments involving a non-native gradient regressive voice assimilation process that is sensitive to the duration of a silent interval between the offset of a partially voiced word-final fricative and the onset of a following voiced or unvoiced stop. Manipulations of precursor rate interacted with assimilation context effects in the interpretation of an /ais/-/aiz/ continuum. These results are discussed in the context of competing interpretations of assimilation context effects and rate normalization. [Work supported by NIH R01DC3108.]
Exploiting waveguide invariant reverberation striations for improved active sonar detection and classification
Authors: Goldhahn Ryan , Rogers Jeff , Hickman Granger , Krolik Jeffrey
Published: October 2013

Active sonar reverberation level (RL) uncertainty is exacerbated in shallow water by multipath propagation and multiple interactions with the bottom. This affects, for example, the statistics of split-window RL estimates used for cell-averaging constant false alarm rate (CA-CFAR) normalization of A-scan returns. For larger signal bandwidths, target detection is impacted by more incoherent reverberation components causing higher background variance while, alternatively, using smaller bandwidth signals results in higher range variability of the mean due to coherent multipath modal interference. In this paper, we present an alternative to CA-CFAR normalization that accounts for the frequency-selective fading characteristics of the multipath channel. The idea is to use the waveguide invariant property to estimate the frequency-dependent reverberation level at the range cell of interest using neighboring range cells at frequencies along striations in the time-frequency distribution of the sonar return. An approximate generalized likelihood ratio test (GLRT) detector is derived and demonstrated on acoustic tank data as well as Mediterranean active sonar data collected during the SCARAB-98 experiment [C. W. Holland, J. Acoust. Soc. Am. (2006)]. Detection and classification results indicate the considerable potential of a waveguide invariant-based approach. [Work supported by ONR321US.]
Sonar target tracking incorporating uncertain estimates of signal to noise ratio
Authors: Fox Warren L. J. , Pitton James W. , Rust Eric A.
Published: October 2013

In the standard approach to sequential estimation for target tracking, tracks are formed on contacts that exceed some predefined detection threshold, set to achieve desired PD and PFA based on an expected SNR and a priori data probability PDFs. If the expected SNR is erroneous, degradation will be observed as either excessive false contacts or missed detections for weak targets. A method known as the Probabilistic Data Association Filter with Amplitude Information (PDAFAI) estimates SNR from the target and interference statistics, and uses the amplitude of the contacts together with the estimated SNR in the track association stage of the tracker. This method requires the PDF for the observed signal. In active sonar, this PDF is dependent on the expected SNR, which is a spatially and temporally varying quantity. Previous work has extended the PDAFAI method by adapting the tracker to the acoustic propagation environment via the measured contact amplitude together with the expected SNR derived from an acoustic propagation model, and by incorporating target strength estimates for contacts in developing tracks. Here, the method is extended further to include probabilistic descriptions of SNR, derived both from uncertainties in estimated environmental (e.g., bottom geoacoustic) and target properties.
Technical Committee on Architectural Acoustics short course presentation material
Authors: Hoover Anthony K.
Published: October 2013

The Technical Committee on Architectural Acoustics (TCAA) is a Registered Provider in the American Institute of Architects (AIA) Continuing Education System (CES). The TCAA has developed a standardized introductory short course for architects, called Architectural Acoustics. An architect can earn one continuing education unit by attending this short course, if it is presented by a qualified member of TCAA. The course covers topics in sound isolation, mechanical system noise control, and finish treatments. This paper will cover the course material in order to prepare and qualify potential presenters. There will be time at the end of the paper for questions and answers on the course material. In order to qualify as an authorized presenter for this AIA/CES short course, attendance at this workshop and membership in TCAA are required.
Chaotic state in an electrodynamic loudspeaker controlled by gas pressure
Authors: Djurek Ivan , Petosic Antonio , Djurek Danijel
Published: October 2013

An electrodynamic loudspeaker with resonant frequency f0=47.1 Hz has been driven in the far nonlinear regime, and f0 increases with increasing driving ac current I0. Landau cutoff of the vibration amplitude appears at frequency fc>f0, which is followed by the doubling of driving period 1/f and appearance of harmonic sequences at 1/2nf, 1/4nf, 3/4nf,.... By further increase of current the white noise spectrum appears, which is characteristic of the chaotic state. Electrodynamic loudspeaker is represented by an ordinary differential equation of motion describing an anharmonic forced oscillator, and it is possible to achieve an independent control of chaotic state by the gas pressure, since real RS and imaginary part XS of the gas acoustic impedance affect, respectively, friction and inertial terms in the equation. The used gas atmospheres (0.01<p<1 bar) were H2, D2, He4, Ne, Ar, CO2, SF6, and air. The cutoff frequency fc depends on the gas pressure and it was plotted against (p,I0), which in turn defines the surface in three-dimensional diagram. Values of parameters (p,I0) triggering chaotic state were chosen above this surface, and universality of some laws describing such state was tested against the gas density.