bluuebunny/crossref_metadata_2025 huggingface dataset:
Relations between auditory functions for tones and speech in impaired bearing
Authors: Plomp R. , Festen J. M. , Dreschler W. A.
Published: October 2005

For two groups of hearing-impaired subjects the correlations between the individual data for different batteries of tests were investigated. The first study (22 subjects) was particularly focused on frequency resolution and temporal resolution at 1000 Hz. In the second study (25 subjects) a wide variety of tests were used, including tests filling the gap between tones and speech. One of the main results is that frequency resolution is closely related to the speech-reception threshold in noise. Further results will be discussed.
The use of construct validity to establish predictive relationships between hearing aid performance and speech understanding
Authors: Smaldino Joseph
Published: October 2005

Factor analyses were used to group 42 hearing aid electroacoustic dimensions. The resultant groups included harmonic distortion, gain, saturation sound pressure level, bandwidth, and regularity of frequency response. Representatives of these groups were entered into multiple regression analyses with listener scores obtained on a continuum of psychoacoustic materials. Results indicated that psychoacoustic scores are influenced by a hierarchy of electroacoustic dimensions and that the hierarchy may be quite different for different materials. This information can be used in a battery approach which produces a constructed validity for establishing prediction between hearing aid performance and speech understanding.
The perception of sine-wave analogs of speech
Authors: Schwab Eileen C.
Published: October 2005

Subjects identified various sets of tone stimuli which consisted of one, two, or three sine-wave components. The stimuli varied in their degree of similarity to the syllables /ba/, /ab/, /ds/, and /ad/. Half of the subjects performed an auditory labeling task in which they identified the direction and location of the pitch transition. The other half of the subjects performed a phonetic labeling task in which they identified the tones as the CV syllables upon which they were based. The results showed a strong interaction between stimulus components and labeling performance. When a low-frequency component (similar to an F1) was present, the phonetic-label subjects performed best while the auditory-label subjects performed worst. Also, various masking effects were present for the auditory-label subjects which were not present for the phonetic-label subjects. The results indicate that phonetic processing is not necessarily invoked by stimulus structure alone. However, when phonetic processing is engaged, the output of auditory analysis becomes unavailable for further processing. These results suggest that auditory and phonetic modes of processing may be mutually exclusive. Furthermore, the findings provide another demonstration of the reality of a distinct speech mode of perception. [Work supported by NIMH.]
Individual differences in the perception of isolated vowels and vowels in a consonantal context
Authors: Rakerd Brad , Verbrugge Robert R.
Published: October 2005

Previous studies comparing the perception of isolated vowels with that of vowels produced in some consonantal context have generally focused on similarities and differences in the average performance of subjects in the two conditions. In this investigation, we wanted to look carefully at individual differences in vowel perception both within and between these conditions. We did so with the aid of a nonmetric individual differences scaling procedure developed by Takane et al. [Psychometrika 42, 7–67 (1977)]. The variance common to all subjects (in the two conditions combined) was modeled in a single multidimensional space, and the individual differences were represented as weights (or saliences) that each subject attached to the dimensions of the space. The data were similarity judgments collected (with the method of triadic comparisons) for a set of isolated vowels and for a set of vowels in context recorded by the same talker. The perceptual space had three dimensions. The first of these corresponded closely to the articulatory dimension of tongue advancement, the second to tongue height, and the third to tenseness. It was consistently observed that subjects who rated vowels in context attached a substantial weight to all three perceptual dimensions. This pattern was also exhibited by several subjects who rated isolated vowels, but others in the isolated vowels condition heavily weighted one of the three dimensions to the near exclusion of the other two, and still others weighted two dimensions substantially but attached little weight to the third. Potential accounts of this condition difference will be discussed. [Work supported by NIH grants HD01994 and RR05596.]
Interactive effects of sensation level, filtering, and consonant environment on the perception of vowels
Authors: Williamson S. , Carney A. E.
Published: October 2005

This experiment assesses the interaction of three factors on vowel perception in normal listeners: filtering, sensation level, and consonant environment. These factors were chosen to provide a more comprehensive analog to vowel perception in the hearing impaired. Sixty subjects were divided into six groups, each group receiving a different experimental condition. Subjects could receive one of three filtering conditions: no filtering, low-Pass, or high-pass filtering, in combination with one of two vowel-environment conditions: isolated or pVp condition. All subjects were presented with stimuli at 10, 20, and 30 dB SL. The vowel stimuli were /i, ɪ, ɛ, æ, ɑ, ɔ, ᴜ, u, ʌ/. All stimuli were produced by a single female speaker in both isolated and pVp conditions. Articulation functions were plotted for each experimental condition. Results indicated a low error rate for subjects in all conditions, even for the lowest sensation levels. Differences between articulation functions were observed between experimental conditions. These data will be discussed with regard to the applicability of such simulations to speech perception and auditory training for the hearing impaired.
Perception of French vowels by native French and American English listeners
Authors: Gottfried Terry L.
Published: October 2005

Studies of American English vowel identification have found that vowels are better identified in consonantal context than in isolation. Strange, Edman, and Jenkins [J. Exp. Psych.: Hum. Percept. Perform. 5, 643–656 (1979)] attribute this finding to dynamic acoustic information carried by formant transitions and vowel duration. One might expect different results for French, because phonological constraints and phonetic characteristics of French vowels are different from those of English. Four native Parisian French speakers produced 11 stressed, oral French vowels in four syllabic contexts: /t/-vowel-/t/ (TVT), vowel-/t/ (VT), /t/-vowel (TV), and isolated vowel (♯V♯). Native French speakers identified vowels in TV and ♯V♯ contexts more accurately than vowels in VT and TVT contexts. In a categorial ABX discrimination task, non-native French speakers and nonspeakers of French also perceived isolated French vowels better than vowels in TVT context, arguing against phonological interpretations of the differences between languages. Acoustic factors accounting for differences in French and English vowel perception are discussed. [Supported by NIMH, NICHHD, NSF, and Graduate School of University of Minnesota.]
Visual speech synthesis for speech perception experiments
Authors: Brooke N. M.
Published: October 2005

Analytical investigations of speech perception in the audio-visual domain require a visual stimulus that is plausibly lifelike, controllable and well-specified. A computer package has been developed to produce real-time animated graphics which simulate the front-facial topography and articulatory movements of the lips and jaw during VCV speech utterances. It is highly modular and can simulate a wide range of facial features, shapes, and movements. It is currently driven by streams of time-varying positional data obtained from experimental measurements of human speakers enunciating VCV utterances. The measurements of a series of point coordinates are made from sequential single frames of a videotape recording using a microprocessor-linked data-logging device. Corrections are made for the effects of global head and body movements. This is the lowest level of control in a hierarchy whose higher levels could include algorithms for generating the articulatory trajectories by rule from phonetic transcriptions. Although the development of the synthesizer is still at an early stage, the acceptability of its display suggests great potential for use in analytical investigations for which the graphics will eventually by synchronized with an audio-speech synthesizer. [Work supported by MRC.]
Detection and resolution of audio-visual conflict in the perception of vowels
Authors: Summerfield Quentin , McGrath Matthew , Foster John
Published: October 2005

To determine whether optical cues can influence the identification of acoustically defined vowels, three series of /bVd/ syllables were synthesized with the medial vowel ranging from /u/ to /a/, /a/ to /i/, and /i/ back to /u/. The members of each series were synchronized with video-recordings of the face of a (natural) talker uttering the end-point syllables of that series, and were presented to adults with normal hearing and vision (a) to obtain ratings of audio-visual compatibility, and (b) for forced choice identification. Perceived compatibility decreased essentially monotonically across each series as the acoustical syllable became less like that normally appropriate for the syllable displayed optically. Nonetheless, systematic changes in patterns of identification occurred between audio-visual and audio-alone presentations, with audio-visual vowels identified as more like the vowel presented visually. These results demonstrate that analogous effects obtained previously with consonants are not restricted to a particular phonetic class, and are compatible with theoretical arguments [Summerfield, Phonetica 36, 314–331 (1979)] that perceptual integration of information in the two modalities occurs prior to phonetic categorization.
Some gas flow and acoustic pressure measurements within concentric-tube resonators
Authors: Sullivan Joseph W.
Published: October 2005

The one-dimensional model of the concentric-tube resonator [J. W. Sullivan and M. J. Crocker, J. Acoustic. Soc. Am. 64, 207–215 (1978)] assumes that (1) the impedance of the perforation is constant along the length of the flow tube and (2) spatial variations of acoustic pressure in the transverse direction of either tube or cavity are small. Some recent measurements on long resonators have indicated that when mean flow is present, net flow in the cavity, although small relative to that in the tube, affects the impedance in a bidirectional manner resulting in violation of assumption (1). Experiments using microphone probes have demonstrated the validity of assumption (2) provided the tube is perforated axisymmetrically. When asymmetric perforations are used, a circumferential cross mode is induced which invalidates the one-dimensional model.
Measurement of acoustic impedance of perforated plates in the presence of mean through flow
Authors: Sullivan Joseph W. , Doige Allan G.
Published: October 2005

Recent developments in muffler research have shown the need for realistic gas-flow models of the impedance of perforations when used in tubes of baffles. The needs and difficulties of measuring the impedance for the singular condition of flow passing through the perforation are examined. Data are presented of the impedance of several perforated plate samples obtained in a flow tube using a swept-sine excitation technique and the two-microphone, transfer function method of measurement.
Investigation into intensity probe obstacle effects and other bias errors of the cross-spectrum intensity measurements
Authors: Kiteck Paul , Tichy Jiri
Published: October 2005

The scattering of the measuring sound field by the finite size intensity probe, used for the cross-spectrum intensity method, can be expected to affect the measurement results. Therefore the effect of one microphone and the microphone holder upon the response of the other microphone was examined for various microphone distances and sizes. Also, the various methods to calibrated for phase and gain mismatch errors between the two measuring systems are compared and evaluated. Finally, intensity bias errors by noncoherent secondary sources and the reverberant environment are experimentally investigated.
Precision noise dosimeter with alarm
Authors: Owusu-Ansah K. A.
Published: October 2005

In noise dosimeters which have been developed, either the frequency weighting networks are preselected manually or only one is incorporated. This can result in loss of precision since the noise level may increase beyond or decrease below the selected range. Secondly, most noise dosimeters need visual attendance which can result in the permissible noise dose being exceded without warning. This paper describes a new design in which the A, B, C frequency weighting networks are selected automatically depending on the noise level. Moreover, an audio alarm system included in the design can be triggered whenever the noise dose limit is reached. It has also visual displays of the cumulative noise level in decibels and the noise exposure factor so that the approach to the critical level can be observed. The dosimeter is lightweight, can be battery operated and can be worn by an industrial worker.
Comparison of combustion and piston slap induced noise in small diesel engines
Authors: Lyon Richard H.
Published: October 2005

Independent studies of the transmission of combustion pressure induced casing vibration and the vibration due to piston slap have been carried out for a small four cylinder diesel engine. These studies are sufficiently analytical in nature to allow one to develop predictable relationships between the strength of combustion and piston slap induced noise for this engine as a function of operating parameters. This paper presents some results of this parameter study and draws conclusions for the design of such engines to reduce noise from these sources.
Examination of slots and cracks with a real-time synthetic aperture acoustic imaging system
Authors: Peterson D. K. , Bennett S. D. , Kino G. S.
Published: October 2005

The construction and operation of a real-time digital synthetic aperture acoustic imaging system will be reviewed. A description of the synthetic aperture reconstruction algorithm and the hardware used to execute this algorithm will be given. Images of both simulated and real flaws will be presented to demonstrate the performance of the imaging system. This system has been used to inspect flaws in solid samples with longitudinal, shear, and surface waves. Some examples of images will be presented to demonstrate the utility of the real-time imaging system in the nondestructive evaluation of structural materials. [This work is supported by the Air Force Office of Scientific Research under Contract No. F49620-79-C-0217.]
A tomographic procedure for mapping an ultrasonic field from acousto-optic data
Authors: Laflin John R. , Cook Bill D.
Published: October 2005

A procedure for mapping an ultrasonic pressure field by applying tomographic processing to acousto-optic data is presented. The procedure is directed toward sound fields with small angular spread such as those produced by NDE and medical ultrasonic transducers. This approach models an interrogating laser beam as a line transducer. The laser beam, therefore, detects only the plane waves in the angular spectrum of the sound field which are propagating normally to the light beam. Also, the relative temporal phase between these plane waves and the transducer input signal is measured. Thus the angular spectrum of the sound field is determined as a phasor field. The data acquisition technique used in this approach allows us to build the angular spectrum of the sound field in approximately a rectangular format, thus allowing the use of conventional FFT algorithms. A knowledge of the total sound field can be obtained from a single tomographic slice if we assume the sound field is described by the Helmholtz equation. Experimental results which show sound pressure distributions over cross sections of various sound fields are presented.
The use of ray theory in locating and sizing cracks
Authors: Norris A. N. , Achenbach J. D.
Published: October 2005

The problem of crack sizing is one of fundamental concern to the nondestructive testing community. In this paper, two methods based on ray theory are proposed for the mapping of cracklike flaws in elastic media. The methods require as input data the arrival times of diffracted ultrasonic signals, which can be either directly measured or computed from high-frequency amplitude spectra. The first method maps points on the crack edge by a process of triangulation with the source and receiver as given vertices of the triangle. By successively shifting the source and/or the receiver incrementally, the direction of signal propagation, which is the necessary constituent required to complete the triangle, can be computed. The inverse mapping is global in the sense that no a-priori knowledge about the location of the crack is necessary. The second method is a local edge mapping which determines planes relative to a known point close to the crack. Each plane contains a flash point. The envelope of the plane maps an approximation to the crack edge. This procedure is an extension of the inversion scheme proposed by Achenbach et al. [Wave Motion 1, 299–316 (1979)].
Controlled retuning of guitar tuned-string groups during musical performance
Authors: Martin Daniel W.
Published: October 2005

The chordal portamento effects produced by the pedal steel guitarist are now widely recognized as musical components of recordings and performances of popular music, especially in the country western category. This paper will describe the instrument, the means by which these effects are achieved, and the physical actions which occur, which are not so well known.
Temporal and spectral characteristics of Tambura tones
Authors: Houtsma Adrian J. M. , Burns Edward M.
Published: October 2005

The tambura is a stringed instrument of the lute type that is used as a drone accompaniment in Indian concert music [V. L. Janakiram and B. Yegnanarayana, J. Acoust. Soc. Am. Suppl. 1 62, S43 (1977)]. A distinctive feature of this instrument is its bridge, which terminates the four strings on a slightly rounded surface rather than on a sharp edge. The instrument is typically played with a silken thread (“Jivali” or “life giver”) wedged between strings and bridge surface, so that the strings “buzz” against the bridge. If the instrument is played without this thread, the curved bridge creates a nonlinear modulation effect by periodically changing the effective string length. Partials up to order 30 are found to be very nearly harmonic. Temporal, short-term spectral and perceptual characteristics of tambura tones played with and without the “jivali” are discussed.
An algorithm for propagating the mutual coherence function
Authors: Perkins John S. , Baer Ralph N. , Wright Evan B. , McCoy John J.
Published: October 2005

We have developed an underwater acoustic propagation model, formulated in terms of the mutual coherence, which can include the effects of random volume scattering. Using a locally quadratic assumption on the index of refraction, a range-stepping algorithm is derived from the parabolic wave equation. Although multipath interference effects (which are apparent when the mutual coherence function is calculated directly from an acoustic pressure field generated by a split-step parabolic-equation model) may be lost due to the locally quadratic assumption, estimates for the output of a vertical array of hydrophones are not seriously affected. Also, when the scattering term of McCoy and Beran [J. Acoust. Soc. Am. 66, 1468–1481 (1979)] is included, the distribution of arriving energy is effectively smoothed over vertical arrival angles.
Investigation of level-crossing statistics as a detection method
Authors: Kenton Arthur Craig , Moritz Elan
Published: October 2005

The statistics of level crossings, including the distribution of time intervals between level crossings, and Palm distributions, are studied for several discretized analytic functions or formatted signals. The effect of noise changing these distributions is analyzed. The presence of a signal embedded in noise may be detected by analyzing shifts of the distributions and, hence, the techniques form a potentially useful and practical signal detection method. Level-crossing statistics augment information obtained from a power spectrum or Fourier analysis. These applications generalize previous studies that were restricted to first-order zero-crossing statistics. Implications for use in the analysis of reverberation are also discussed.
Performance model for square law detectors followed by accumulators and an O-ring device
Authors: Struzinski William A.
Published: October 2005

A mathematical model is presented to determine the performance of square law detectors followed by accumulators and an O-ring device. The performance of a deterministic signal in Gaussian noise is determined for a specified number of channels O red. The performance (threshold reduction) is computed as a function of the number of samples in the accumulator preceding the O-ring device for various fixed input signal-to-noise ratios to the square law detector. In addition, the number of samples required in the accumulator for a 0-dB performance loss is also presented. Finally, a comparison is made to results presented in a previous paper [W. A. Struzinski, J. Acoust. Soc. Am. Suppl. 1 70, S16 (1981)] where the O-ring device preceded the accumulator. It is concluded that O ring after integration yields a much lower signal-to-noise ratio loss than O ring before integration. [This work is sponsored by the Naval Sea Systems Command.]
Results from rail synthetic aperture experiments
Authors: Loggins C. D. , Christoff J. T. , Pipkin E. L.
Published: October 2005

A specially designed sonar rail facility was used to collect synthetic-aperture sonar data in the frequency range from 20 to 100 kHz. A target field laid out at the rail site containing simulated point objects was used to measure the beamforming performance of synthetic-aperture sonar at these frequencies. The synthetic-aperture beam patterns obtained in these tests show excellent compression in azimuth and have side-lobe levels of about-17 dB. The mechanical and electronic features of the sonar rail facility are described, and the experimental procedures outlined. A passive auto-focus technique used to correct rail nonlinearities is described, as well as measurements made to determine the temporal coherence of the medium at the rail site.
Detectability of interaural phase shift as a function of frequency
Authors: Kunov Hans , Abel Sharon M.
Published: October 2005

Previous research [S. M. Abel and H. Kunov, J. Acoust. Soc. Am. Suppl. 1 69, S63 (1981)] indicated that the envelope cue contributed by rise/decay (R/D) of sinusoidal signals had little effect above 1500 Hz but affected lateralization below 1250 Hz. The relationship between R/D and frequency was studied in detail. Binaural signals were presented 180° out of phase, and the entire signal was delayed randomly to the left or right ear. Plots of P(C) versus the reciprocal of R/D on normal probability paper indicate a linear relationship between 20 and 700 ms. The slopes show that the use of the envelope cue peaks at approximately 1000 Hz, falling to near 0 before 2000 Hz. In a subsequent experiment, using R/D sufficiently long (700 ms) to eliminate the envelope cue, the effect of frequency on phase detection was examined, especially between 1200 and 1700 Hz. Psychometric functions were determined for interaural phase shifts (θ) close to 0° and 180°. At 1000 Hz, their slopes were approximately 8 %/deg and −2 %/deg, respectively, both falling linearly to 0 around 1600 Hz. The data from these two experiments provide quantification of the use of envelope and phase cues with frequency.
Interaural intensity discrimination of noise as a function of center frequency, duration, and interaural correlation
Authors: Grantham D. Wesley , Ahlstrom Jayne B.
Published: October 2005

Interaural intensity difference thresholds were determined for three bands of Gaussian noise: a wideband noise (100–5000 Hz) and two 0.4-octave narrow bands (48 dB/octave skirts) centered at 500 and 4000 Hz. Thresholds were estimated from psychometric functions generated employing a two-interval forced-choice blocked procedure, in which the nominal interaural intensity difference on each trial was divided between the two ears. Reference intensity was 70 dB SPL (overall). StimUlus duration (30 or 500 ms) and interaural correlation of the noise (0.0 or 1.0) were parametrically varied. For the 500-ms stimulus durations thresholds were near 1 dB (12-dB change in either ear alone) for all types of noise and for the two values of interaural correlation employed. For the briefer (30 ms) stimuli thresholds varied from about 1.3 dB (for wideband, interaurally correlated noise) to about 3 dB (for narrow noise centered at 500 Hz, interaurally uncorrelated). The results will be discussed in terms of the tradability of bandwidth, duration, and interaurally redundant information available in noisy stimuli. [Supported by NSF.]
Sphere-cylinder discrimination by human observers using broadband sonar pulses
Authors: Martin Douglas W. , Au Whitlow W. L.
Published: October 2005

Human listeners were presented with target echoes and were asked to indicate which of two target classes, spheres or cylinders, generated the echoes on each trial. Sessions were conducted using either one or two targets from each class. Stimuli were obtained using broadband, ultrasonic, dolphinlike pulses, which were digitally recorded and presented to subjects at 1/50 of the original sample rate. Stimuli thus presented had center frequencies of approximately 2.4 kHz and durations of approximately 50 ms. Targets included spheres and cylinders of various sizes made of solid foam, solid aluminum, and hollow steel. After training, the average probability of correct discrimination with the foam targets varied between 85% and 96% depending on which targets were included in a session. Discrimination between the metal spheres and cylinders always exceeded 90% in both two- and four-target sessions. For both foam and metal targets, subjects reported using two discrimination cues: a higher pitch associated with the cylinder echoes, and more low-frequency reverberation in the sphere echoes. While the target strength of cylinders increases with frequency, and that of spheres does not, the targets could not be separated into classes based only on observing their spectra.
Directionality of sound pressure transformation at the cat's pinna
Authors: Phillips Dennis P. , Calford Michael B. , Pettigrew John D. , Aitkin Lindsay M. , Semple Malcolm N.
Published: October 2005

In anesthetized cats, pinna directionality was examined using the amplitude of the round window-recorded cochlear microphonic as a quantitative indicator of tympanic sound pressure level (SPL) associated with free field tonal stimuli in anechoic space. For high frequencies (above 3.5 kHz), there was a circumscribed optimal area for tympanic SPL in the frontal ipsilateral sound field, confirming that the pinna has an acoustical axis. The directionality of the pinna, determined from the solid angle enclosed by the 5-dB optimal area, increased with tonal frequency. Few low frequencies, no circumscribed optimal areas could be discerned. Excision of the pinna abolished the circumscribed optimal area for tympanic SPL and revealed that the pinna may produce up to 30-dB amplification of tonal stimuli delivered “on-axis.” This selective directional amplification is compatible with the view [J. C. Middlebrooks and J. D. Pettigrew, J. Neurosci. 1, 107–120 (1981)] that apart from a role in sound localization, active pinna movements could be used by the cat for the scrutiny of sound sources of interest at the expense of others.
Use of elastomeric isolation for attenuation
Authors: Andrew Frank
Published: October 2005

The use of elastomeric isolation to provide structureborne noise attenuation frequently results in less attenuation than would be predicted using the classical transmissibility equation. Some of the factors which make the attenuation less than predicted include: insufficient impedance mismatch between the isolator and mounting structure, strain sensitivity of elastomers, wave effects, rocking modes, and structural resonance. This paper discusses these factors and presents data to show their significance.
Wire rope resilient mounts
Authors: Lekuch Herb
Published: October 2005

Constructed of cres wire rope and aluminum retainer bars, helical isolators combine a very wide load range with multi-axis compliance that permits their use in any attitude. Their large dynamic displacement attenuates severe shock while inherent 15%–20% of critical damping, resulting from wire rope interaction, also makes them effective in vibration control. In compression, they exhibit a softening load-deflection charcteristic. In tension, bilinear stiffening is evident. Other applied force attitudes show strongly nonlinear characteristics which may be softening or stiffening, depending on the range of interest, and direction of applied load. Due to the materials of construction, performance is unaffected by temperature extremes. Successfully used in several of the Navy's gyro containers, shock response averaged 15's in any direction from 21-in. drop height for 1- to 10-lb payload, and from 18-in. drop for 8- to 35-lb payload. Test results and a description of isolation system design is given. Test technique and data analysis are discussed, and guidelines for mount selection is presented. Also given, will be a description of isolator construction loop profile, wire rope selection and the influence of these parameters on nonlinear restoring forces.
Acoustic emission measurements of a shape-memory alloy
Authors: Geng R. S. , Britton W. G. B. , Stephens R. W. B.
Published: October 2005

A description is given of a systematic study of the acoustic emission (A.E.) characteristics of a specific shape-memory alloy, a copper-based Betalloy. Using a narrow-band A.E. measuring system, a considerable change in A.E. signals was observed in the different phase states of the Betalloy, the changes being particularly significant in the slope changes of the amplitude-distribution curves. By careful correlation of A.E. signals with the stress-induced martensitic transformation it was found, in repetition cycles, that a reversible A.E. energy release accompanied the austenite-martensite transition process, which is in direct conflict with the “Kaiser effect.” This observation implies that caution is necessary in applying the A.E. technique for evaluating failure in shape-memory alloys. The values derived from the A.E. data for the stress required to induce martensitic transformation and for the temperature at which the transformation is initiated are in goad agreement with those obtained from stress-strain measurements.
Simple model for low-frequency guitar function
Authors: Christensen Ove , Vistisen Bo B.
Published: October 2005

The frequency response of sound pressure and top plate mobility was measured around the two first resonances of the guitar. These resonances are shown to result from a coupling between the fundamental top plate resonance and the Helmholtz resonance of the cavity. The Helmholtz resonance is found as an antiresonance in the mobility response but it is not seen directly in the sound-pressure response. A simple two-oscillator model is presented for guitar function at low frequencies. All parameters of this model are determined from experimental measurements of the frequencies of the two first resonances and of the Helmholtz cavity resonance. The model reproduces quantitatively the experimental frequency response of sound pressure and of top plate mobility. The influence of the back plate of the guitar is investigated from a similar three-oscillator model. [Work supported by SHF.]
Passive resonance frequencies of flute structures
Authors: Strong William J. , Fletcher Neville H. , Silk Ron K.
Published: October 2005

Numerically calculated impedances for flute structures may be useful for exploring how changes in design parameters affect resonance frequencies. Any numerical method should be validated by comparing its results with experimental data. A successive impedance method was used to numerically calculate passive resonance frequencies from the dimensions of a Powell flute. Calculations were made for a given embouchure condition with different fingerings and for the middle and foot joints with different fingerings. The numerical results are compared to experimental results obtained for the same flute [John W. Coltman, J. Acoust. Soc. Am. 40, 99–107 (1966)]. The numerical results typically differ from the experimental data by a few cents, although some differ by as much as 20 cents. Similar comparisons are made for octave stretching with discrepancies of as much as 10 cents. [Work supported in part by Australian-American Educational Foundation.]
Second-harmonic sound generation at woodwind tone holes
Authors: Richards W. B. , Benade A. H.
Published: October 2005

Keefe has observed the importance of nonlinear processes in the tone-hole lattice of a woodwind instrument. Using a probe microphone, we have investigated second-harmonic generation in the neighborhood of the first open tone hole of two cylindrical air columns driven at 200 Hz. The two lattices have tone holes with identical input impedance, but one has tone holes whose chimney height is small compared to the hole diameter, while the other has chimney height nearly the same as the hole diameter. When the SPL in the center of the bore opposite the tone hole is 107 dB, the sound waves in the two tone-hole lattices have similar second-harmonic content, −26 dB relative to the level of the fundamental. (The second harmonic contributed by the driver is 36 dB below the level of the fundamental.) When the mid-bore SPL is 122 dB, the second-harmonic level within and immediately outside the short-chimney hole rises to −11 dB relative to the fundamental, while the tall-chimney tone hole is at −17 dB. (At this level, the second harmonic at the driver is still negligible.) Streaming from the tone hole is present in all measurements, but the 3-dB width of the second-harmonic spectral component is less than 0.08 Hz at all SPL. The large second-harmonic component does not propagate away from the region of the tone hole: it drains energy from the fundamental mode of oscillation, but does not contribute to the sound field in the room nor to the operation of the flow-control valve at the top of the instrument. [Work supported by NSF.]
Flexible fiberoptics for evaluation of the larynges of horn and woodwind players in performance. An audiovisual concert
Authors: Selkin Stuart G.
Published: October 2005

Viewing the larynx has been revolutionized by the advent of flexible fiberoptic scopes. A subject may inspire, expire, cough, swallow, and phonate as examination precedes. The stunningly clear images may be adapted for production of color transparencies, prints, and color and sound videotapes. Using techniques he has devised, the author presents color and sound videotapes of the larynges of musicians as they play woodwind and brass instruments. Performers vary in age and experience from college freshmen to university faculty members.
A pole sorting approach to separate the source and vocal tract spectra
Authors: Milenkovic P. , Olive J. P.
Published: October 2005

A speech spectrum is a product of the source spectrum and the vocal tract shape spectrum. Most analysis techniqus do not differentiate between the source and the vocal tract spectrum. The poles derived from an LPC analysis of the speech signal describe the influence of both source and vocal tract functions. This paper will describe a method to separate the LPC derived poles into two groups describing the source and vocal tract spectrum. The major criterion used in the algorithm was the spectral flatness of the source. In order to evaluate this method, the vocal tract poles were used to control a series formant synthesizer driven by a fixed source.
Piano touch, hammer action, and string motion
Authors: Askenfelt Anders G. , Jansson Erik V.
Published: October 2005

Simultaneous recordings have been made of key velocity, hammer acceleration, and string velocity of two grand pianos. In the experiments it was found that the course of the key velocity varies depending on whether the finger motion is initiated from a position above the key or in contact with the key. The course of the hammer velocity varies somewhat with the key velocity; high key velocity shortens the hammer-key contact time, and low key velocity increases this time. The hammer hits the string approximately at the same moment as the key hits its bottom position. Recordings of string displacement show that in the very low register the starting pulse is considerably shorter than half a period of the string fundamental, in the middle range it is approximately half a period, and in the high register it is considerably longer than half a period and also its amplitude is considerably larger than that of the following half-period.
A kinetic model approach to Rayleigh's treatment of the effect of gravity on sound velocity
Authors: Agrawal D. C. , Menon V. J.
Published: October 2005

About a century ago Rayleigh [The Theory of Sound (Dover, New York), Vol. 2, p. 288] had evaluated the effect of gravity on the velocity of sound by assuming an adiabatic atmosphere in hydrostatic equilibrium under gravitational stress. He showed that the sound velocity c(z) at altitude z is c(z) = [c2 (0) − (γ − 1) gz]1/2, where γ is the ratio of the specific heats at constant pressure to constant volume. This paper is aimed at deriving a result analogous to Rayleigh's by applying a classical kinetic model of a gas in thermal equilibrium placed under gravity. The elastic properties, together with the propagation of sound in this medium, are discussed and WKB solutions to the wave equations are derived explicitly. The velocity of sound in the normal region is shown to be c(z) = [c2 (0) − γ (γ − 1) gz]1/2. Because of energy equipartitioned the velocity of sound traveling within a layer parallel to the ground at altitude z has a constant magnitude given by the same formula. Further theoretical and experimental implications of it are underway.
Fiber coating optimization for interferometric acoustic sensors
Authors: Lagakos N. , Cole J. H. , Bucaro J. A.
Published: October 2005

The pressure sensitivity of the induced phase modulation in fiber optic acoustic sensors is studied both analytically and experimentally. The elastic parameters of commonly used coatings (thermoset plastics and acrylate based U. V. curable coatings), which govern the sensitivity, have been studied in bulk samples as a function of frequency (102–104 Hz) and temperature (0°–35 °C). The analysis, which takes into account the exact composition and geometry of multilayer fibers, is utilized to identify coatings which optimize the fiber acoustic sensitivity. The analytically predicted frequency dependence of the acoustic sensitivity is found to be in agreement with that obtained experimentally using fibers with various coatings.
Compressibility of polymer colloids. I. Ultrasonic study of aqueous solutions of polymers and their adsorbed state on polystyrene latex
Authors: Gültepe M. A. Barrett , Gültepe M. E. , Yeager E. B.
Published: October 2005

In earlier work [M. A. Barrett Gültepe, D. H. Everett, and M. E. Gültepe, A.C.S. Publications, Polymer Colloids, Vol. 2 (Plenum Press, New York, 1980)] it was shown that ultrasonic absorption in dispersions of colloidal particles are strongly influenced by the nature of the electrolyte particle interface, and that an adsorbed layer of a block copolymer on the particle surface considerably alters the acoustic properties of the interface. In the present study the influence of the interface on the compressibility of the dispersion has been studied. A 2-MHz interferometer was used to determine the adiabatic compressibilities of aqueous dispersions of polystyrene latex as a function of volume concentration (up to 42%) and temperature (approaching the glass transition temperature). Velocity measurements were also made in solutions of 72% and 78% hydrolyzed polyvinyl alcohol-polyvinyl acetate block polymers (PVA) as a function of temperature above and below their cloud points. The measurements were extended to the latex covered with the PVA in a manner known to give a 30-nm layer consisting of 13% PVA. The dispersion gives a resultant compressibility lower than expected from the simple additive effect of the separate components at low temperatures, while the reverse is true at high temperatures. The decrease in compressibility is possibly due to the hydrophobic interaction between the acetate groups and the polymer backbone of the polystyrene latex. [Work supported by ONR.]
A small pressurized chamber for low-frequency characterization of acoustic materials
Authors: Hagelberg M. Paul , Corsaro R. D. , Jarzynski J. , Edwards P. L.
Published: October 2005

A system will be described for measuring the acoustic properties of material in water under free field conditions. The system makes use of digital data acquisition and analysis techniques and transducer arrays to cover the frequency range down to about 10 kHz and at pressure to above 100 psi in a compact vessel. Physical and eletronic features of the system will be presented together with the procedures by which the sound speed and attenuation and related characteristics of the sample may be determined. Results will be presented for a silicone rubber, a filled silicone rubber, and the commercial product Sorbothane. [M. P. Hagelberg was involved in this research as a participant in the NAVY-ASEE Faculty Research Participate Program.]
The effects of different speech stimuli on the measurement of speech intelligibility under conditions of high frequency range and frequency response irregularity
Authors: Bornstein Steven P. , Randolph Kenneth J. , Maxon Antonia , Giolas Thomas
Published: October 2005

The effects of the electroacoustic parameters of frequency response smoothness and high frequency range have been demonstrated to have significant effects on speech intelligibility in noise [S. P. Bornstein et al., J. Acoust. Soc. Am. Suppl. 1 70, S105 (1981)]. However these effects were dependent on the type of speech material used, the Tri-Word Test of Intelligibility [L. Sergeant et al., J. Acoust. Soc. Am. 65, 218–223 (1979)] or the Nonsense Syllable Test [H. Levitt et al., Communication Sciences Laboratory Research Report ♯11, City University of New York (1978)]. Further analysis revealed that the Nonsense Syllable Test was more sensitive to detecting differences in performance as a function of high frequency range, while the Tri-Word Test was more sensitive to frequency response parameters. These findings will be discussed in terms of the specific effects these electroacoustic parameters have on speech perception, and the validity of intelligibility tests for research and clinical purposes, particularly regarding applicability to persons with impaired hearing. Also, the variability associated with each test will be discussed.
Evaluating voice communication systems using naive talkers or experienced communicators
Authors: Schmidt-Nielsen A.
Published: October 2005

Two groups of subjects were used to obtain conversational test evaluations of digital voice processors with data rates from 800 to 32 000 bits/s. One group consisted of paid subjects with no previous experience, and the second group, of radio amateurs with hundreds of hours of communication experience. Each group was tested using two conversational measures, the Free Conversation Test, which has an open vocabulary, and the NRL Communicability Test [A. Schmidt-Nielsen and S. S. Everett, J. Acoust. Soc. Am. Suppl. 1 70, S108 (1981)], which uses a closed vocabulary. Experienced and inexperienced talkers gave very similar rankings to the voice systems. Any differences fell within categories where the systems were not significantly different from one another. The experienced communicators were more tolerant of degradation than were the inexperienced subjects and gave better ratings to low quality systems. Better discrimination among voice systems was achieved when inexperienced talkers were used in the tests. Reasons for these results will be discussed in terms of different coping strategies for the two groups of subjects.
On the distinction between prosodic and semantic factors in word identification
Authors: Miller Joanne L. , Green Kerry , Schermer Trude
Published: October 2005

Two factors contributing to the identification of a word are the prosody of the sentence in which the word occurs and the semantic relation between the word and its context sentence. To investigate further these two factors, we created a series of target words that ranged from “bath” to “path” by systematically varying word-initial voice-onset-time, placed these words in a number of different sentence frames, and asked listeners to identify each word as “bath” or “path.” Both the speaking rate of the sentence and the semantic congruity between the target word and the sentence affected the way in which acoustically ambiguous words were identified. However, the effects were quite different in nature. Whereas a change in speaking rate influenced word identification even when the listener was not required by task demands to attend to the context sentence, a change in semantic congruity altered identification only when attention to the context sentence was required. This suggests that in the course of identifying a word the processing system automatically takes into account the prosodic structure of the utterance, but not its semantic content. The implication of these findings for models of word recognition will be discussed.
Priming the phonemic restoration illusion
Authors: Nusbaum Howard C. , Walley Amanda C. , Carrell Thomas D.
Published: October 2005

When a portion of a spoken word is replaced by noise, listeners tend to perceptually restore the missing information. Recently, it has been shown that this phonemic restoration illusion is facilitated by the presentation of an intact version of a word prior to the same word with noise replacement [A. G. Samuel, J. Exptl. Psychol.: General 110, 474–494 (1981)]. The effects of this intact word prime on phonemic restoration may be attributed to either or both of two perceptual processes. One possible locus of this priming effect is phonemic encoding. The second possibility is the top-down flow of information produced by lexical access. To dissociate the potential effects of phonological and lexical priming, the relationship between prime and test word was systematically varied. Subjects participated in: (1) a no prime condition, (2) a dissimilar word prime condition, (3) an identical word prime condition, and (4) a pseudoword prime condition in which the primes were phonologically matched to the test words. The interval between prime and test word was also varied. Signal-detection analyses of the data provided separate measures of changes in discriminability and response bias across these conditions. The results have implications for theories of word recognition, lexical access, and the interaction of knowledge sources in spoken language understanding. [Work supported by grants from NIMH and NINCDS.]