bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptual aspects of some voice qualities
Authors: Colton R. H. , Estill J.
Published: October 2005

The perceptual dimensions related to the identification of four common, normal and distinct voice qualities were investigated. The qualities were representative of those heard (1) in everyday speaking (speech), (2) when someone produces a low-level whimper or cry (cry), (3) in country-western twang (twang), and (4) on the operatic stage (ring). Five subjects produced examples of these qualities at different fundamental frequencies. Thirty observers listened to tapes composed of combinations of the subject's paired stimuli and rated the degree of voice quality difference between the members of the pairs. The observers' dissimilarity matricies were then the input to INDSCAL. Depending on the subject who produced the simulus, three or four dimensions accounted for 43%–55% of the observers variance. In general, the most important dimension was Pitch followed by Nasality. Other dimensions included Brightness, Space, and Texture. Observers with different experimental background tended to weight the various dimensions somewhat experimental background tended to weight the various dimensions somewhat differently. The perceptual dimensions discovered help to explain the perceptual confusions that were noted when the same observers were asked to identify the same stimuli.
Speaker identification from photographs
Authors: McGlone Robert E. , Hicks James W.
Published: October 2005

This speaker identification study attempted to determine if listeners could match an individual's photograph and a recording of their speech. Fifteen young adult females served as speakers. Each, in the opinion of the investigators, spoke with a homogeneous Southern dialect. The said the phrase “How are y'all doin' today.” and the second sentence of the “Rainbow Passage.” Recordings were made in a quiet environment and front photographs (from the waist up) were made prior to the recordings. Slides made from the photographs were paired and presented to two groups of naive listeners for their identification by a binary forced-choice procedure. Group one consisted of 32 listeners and group two of 29. The “How are y'all doin' …” phrase was played first and “The rainbow is …” was played second. Lass and Harvey, [J. Acoust. Soc. Am. 59, 1232–1236 (1976)] using a similar procedure found that listeners could make such identifications significantly better than chance. The results of the present study showed that group one made identification above chance on both phrases and group two below chance in each category. Combined scores were chance.
The influence of the period and the duty cycle of an intermittent noise on the acoustic reflex activity
Authors: Lalande Nicole , Hétu Raymond
Published: October 2005

The effect of varying the period (0.4, 4, 40, and 400 s) and the duty cycle (0.25, 0.50, and 0.75) of an intermittent pink noise on the acoustic reflex was investigated with five normal hearing adults. The intermittent signals were presented monaurally during 16 min at a RMS level of 105 dBA and the change in acoustic compliance was measured continuously in the opposite ear. The percentage of change in the on-responses (OR) was analyzed in reference to the median values obtained during the first 20 s of exposure. For all the periods selected no change could be observed in the ORs after 14 min of exposure when the duty cycle was 0.25. The OR decayed from 4.5% to 13% when the duty cycle was 0.50. Similar results were obtained with the 0.4 and the 400-s periods under the 0.75 duty cycle. But, in the latter case, the periods of 40 and 4 s induced reductions of the OR in percentages as high as 19.5 and 34, respectively, after a 14-min exposure. These results suggest that the reduction in reflex excitability under intermittent exposure depends on critical durations of both noise and quiet intervals.
Lateralization of clicks presented at a rapid rate based on interaural differences of intensity
Authors: Hafter E. R. , Dye R. H. , Wenzel E. S.
Published: October 2005

Previously we have shown [J. Acoust. Soc. Am. 64, S35–S36 (1978)] that lateralization of trains (of length n) of 4000 Hz, bandpass clicks on the basis of an interaural difference of time (IDT) is related to the interclick interval (ICI) in a way which suggests a dynamic—rather than a stationary—process description of neural refractory periods. This was indicated by a linear relation between log threshold (ΔIDT) and log n, where the slope (k) grew more shallow as the rate of presentation (I/ICI) increased. It lead to the suggestion that the number of neural events (N) evoked by the clicks could be described by the simple relation: [N = nk; 0 ⩽ k ⩽ 1; k = f(ICI)]. An exponential decline in efficiency such as this would occur, for example, if each click had a proportionately lower probability of evoking a response than the one before. In the present study, listeners lateralized trains of clicks similar to those above, only here, on the basis of an interaural difference of intensity (IDI). The results are essentially the same as with time, with the slopes of the functions relating log ΔIDI to log n decreasing for shorter ICIs. [This work was sponsored by a grant from the NIH, NS-07787.]
Melodic accent
Authors: Thomassen J.
Published: October 2005

Contrary to temporal and dynamic accentuation, melodic accentuation has received little interest in the literature. Melodic accentuation is comparatively subtle. Therefore a sensitive method is required. It turned out that the method of controlled anticipation provides good results. This method involves the embedding of the short isochronous, equal loudness, pure tone sequence to be investigated in a larger, also isochronous, sequence of tones, the sound level of which is manipulated in such a way as to control the anticipation of the observer. Coincidence of perceived and anticipated accents then leads to the experience of “regular rhythm” (tape demonstration). It was found that melodic accents are brought about mainly by the pitch contour and to a lesser extent by the magnitude of the pitch changes. A model was constructed describing accent perception in terms of relations between tones within a window proceeding along the tone sequence. A memory span of only three tones is shown to be sufficient to predict accents in four successive tones using experimental data obtained for three successive tones. The musical relevance of these findings will be discussed. [Work supported by Dutch Psychonomics Z.W.O.]
Perception of crescendos as a function of duration
Authors: Mathews M. V.
Published: October 2005

A theory is proposed that the perceived strength of a crescendo depends on its duration and that very short and very long crescendos will seem weaker than crescendos of moderate duration. Crescendos of varying durations and equal intensity change in decibels were generated with a computer and were rated by a group of listeners on a one-to-ten scale. The perceived strength of otherwise equal crescendos increased steadily as the duration increased from 0.04 to 10 s. Thus short crescendos were weak, but long crescendos were not. Crescendos with equal decibel change but with various average intensities were generated. The crescendos with greater average intensity were judged to be stronger. This interaction between average intensity and duration may explain why long crescendos do not seem weak.
Prestimulus perceptual activity in perception of tone in musical sequences
Authors: Boomsliter Paul C. , Creel Warren
Published: October 2005

Acoustical concepts of tone were formed in an age when psychologists thought of a perceiver as responding directly to a stimulus. Psychological thinking has shifted in recent decades; in many cases now, a stimulus is thought of as modifying a complex of interacting processes that were already in progress before the stimulus arrived. Short tone experiments show that an unprepared listener requires observable time to achieve tonal sensation, and yet more time to achieve appropriate pitch sensation. Abnormal cases throw light on the normal; findings before and after surgery to improve brain stem function on 55 patients are presented. Within musical sequences we experience tone and proper pitch without any such delay, indicating that each stimulus has been preceded by prestimulus perceptual activity. The fact that composers of tonal music tend to use only limited combinations, and the fact that variation from desired pitch is experienced as change in tone quality rather than in pitch, support this interpretation. [Supported in part by Public Health Service Grants HE-08179 and 5M01FR0094 from the National Institutes of Health and by the Danforth Foundation.]
On increasing the intelligibility of sung vowels
Authors: Smith Lloyd A. , Scott Brian L.
Published: October 2005

The intelligibility of the front vowels (/i/, /l/,/ε/, and /æ/) was investigated as sung in four different ways: (1) operatic, (2) in CVC context, (3) with a raised larynx, and (4) with both raised larynx and in CVC context. All syllables were sung by a trained soprano at F4, A4 C♯5, F5, A5, and C♯6. Ten subjects listened and identified randomized sets of ten tokens of each vowel per condition (method of articulation) at each pitch. Results showed that, from C♯5 (554.4 Hz) to F5 (698.5 Hz), the intelligibility of operatic vowels (condition 1) fell from 56% to 16%. The mean intelligibility of the vowels at the three highest pitch values (F5, A5, C♯6) was 10% for condition 1, 64% for condition 2, 62% for condition 3, and 83% for condition 4. Probable reasons for increased intelligibility across conditions will be discussed. The results indicate that the generally accepted notion that vowel sounds are largely unintelligible at higher pitch values pertains only to a restricted manner of production.
Why is the typical noise dose of humans important?
Authors: Johnson Daniel L.
Published: October 2005

A short overview on the rationale for organizing this session is provided. The state of the art of dosimetry is briefly summarized and predictions as to what will be needed in the future are made. The use of dosimetry for assessing nonoccupational noise exposure is discussed. A summary of what current noise dosimetry can and cannot accomplish is made.
Basic problems caused by depth and size constraints in low-frequency underwater transducers
Authors: Woollett R. S.
Published: October 2005

Scaling of a conventional transducer design to very low frequencies usually leads to greater power than needed and greater size than is considered tolerable. Normally, therefore, scaling guidelines are abandoned, and very low-frequency transducers are miniaturized, that is, made with dimensions much smaller than the sound wavelength. The resulting low-radiation resistance leads to high mechanical Q, poor power-to-weight ratio, and poorly behaved driving point impedance. By employing electrical equalizers and acoustoelectrical feedback, the designer can achieve broad bandwidth in spite of the high Q, but an oversized driving amplifier is required. Transducers that operate at full ocean depths are usually liquid filled. The stiffness of the interior liquid increases the transducer size and tends to raise its Q and lower its coupling factor. A Helmholtz resonator configuration is often advantageous in this situation. For more moderate depths, compliant tubes or compressed gas may be used to reduce the stiffness of the interior. However, depth capability is always obtained at the expense of acoustic performance. [Work supported by NAVMAT, R. R. Smith program manager.]
Bender bar transducers for low-frequency underwater sound sources
Authors: Sheridan C. A. , Akervold O. L.
Published: October 2005

During the past 16 years. Bender bar transducers have been used extensively for low-frequency sound source applications, exhibiting high repeatability and reliability. The high impedance of the piezoelectric ceramic is effectively matched to the lower acoustic impedance of water through the large deflection and surface areas of flexural mode transducers. This paper presents a discussion of the method of Bender bar operation and implementation and performance capabilities and limitations. Performance and physical descriptions of selected Bender bar transducers and transducer systems are shown. Design and performance considerations for using Bender bar transducers in broadband noise systems and driver amplifier considerations are included. Modifications to Bender bar transducer design configurations to meet projected low-frequency sound source applications requiring lighter-weight broadband operation are discussed.
The air gun impulsive underwater transducer
Authors: Burger James E.
Published: October 2005

Air guns are effective transducers of impulsive low-frequency underwater sound. They are commonly arrayed to be the sound source in marine geophysical seismic exploration systems. Individual guns from these arrays radiate up to 180 kJ per shot in about a 5-Hz frequency band centered at about 10 Hz. The bandwidth and fundamental frequency can both be increased by increasing the detonation depth. It is necessary to modify the seismic air guns, however, if their radiated energy is to be as large at frequencies above about 50 Hz as it is at lower frequencies. Three different air guns are described, each one having good acoustical efficiency over the range of fundamental frequencies extending from 10 to 120 Hz. A summary for each air gun describes its power requirements, and its fundamental frequency and energy source level as functions of depth. It is observed that air guns that make cylindrical bubbles operate at higher fundamental frequencies than do air guns that make spherical bubbles having the same bubble energy.
Resonating fields inside elastic scattering objects
Authors: Flax Lawrence , George Jacob , Überall Herbert
Published: October 2005

The resonance theory of acoustic scattering from elastic objects [L. Flax, L. R. Dragonette, and H. Überall, J. Acoust. Soc. Am. 63, 723 (1978)] predicts the field exterior to the scattering object to consist of resonance terms, superimposed on a nonresonant background which corresponds to the scattering amplitude for an impenetrable object. in contrast, the interior field is predicted to consist of resonant amplitudes only, so that a substantial amount of penetration of the incident field into the scatterer occurs only at and near the resonance frequencies of the body. We have made quantitative numerical studies of the interior fields in glass cylinders imbedded in water, and subject to incident acoustic fields from far-distant or nearby line sources. The results are compared to, and agree with, experimentally measured fields inside glass cylinders as visualized by the method of optic-elastic birefringence [E. K. Sitting and G. A. Coquin, J. Acoust. Soc. Am. 48, 1150 (1970)]. [J. G. and H. U. were supported by the Office of Naval Research, Code 421.]
Mode conversion and resonance scattering of elastic waves from a cylindrical fluid-filled cavity
Authors: Solomon S. G. , Überall H.
Published: October 2005

Mode conversion and scattering of compressional and shear waves from cylindrical cavities are studied by performing partial wave expansions of the incident and scattered fields. Our analysis, supported by extensive numerical calculations, shows that each partial wave spectrum consists of a smooth background identical to that of an empty cavity and a series of resonance terms associated with the eigenvibrations of the cavity's fluid interior. The scattering matrix for the cavity is defined and its unitary and symmetry properties are discussed. Argand diagrams of the trajectories of the S-matrix elements in the complex plane are shown to have certain easily recognized features which are associated with the cavity resonances. [H. Überall was supported by the Office of Naval Research, Code 421.]
Creeping waves, shadow zones, and acoustic energy conservation
Authors: Pierce Allan D.
Published: October 2005

Creeping waves can propagate along a solid surface or a surface within the fluid if the geometrical acoustic rays initially tangential to the surface eventually diverge from the surface. The creeping wave is characterized for a given propagation direction by an effective relative curvature radius R. For a creeping wave propagating along a flat rigid surface above which the sound speed decreases with height, R is c/|dc/dz|. For a wave propagating along a spherical surface in a homogeneous medium, R is the radius of the sphere. As the wave propagates along the surface, it continually sheds geometrical acoustic rays that transport energy into the shadow zone. Paper derives fundamental expression for the acoustic energy shed per unit area of surface. Conservation of energy considerations then yield an expression for the energy per unit area intrinsically associated with the creeping wave. At points somewhat removed from the surface, the mean-squared pressure decreases exponentially with distance from the shadow zone boundary, the decay constant being proportional to f1/3 and to the reciprocal of the distance along the shadow zone boundary from the point at which the creeping wave was launched. The analysis reproduces Pridmore-Brown's and Ingard's classic result for the decay constant, but gives it a simpler physical interpretation that is applicable to a wider variety of circumstances.
Acoustically evoked neurophysiological responses in guinea pigs' central nervous system after complete amikacin destruction of the organs of Corti
Authors: Aran J.-M. , Cazals Y.
Published: October 2005

In guinea pigs treated with large doses of the aminoglycoside antibiotic amikacin (14 × 450 mg/kg, IM) and presenting with total loss of outer and inner hair cells, except for very few outer hair cells at the apex, a very short-latency (0.3 ms), well-synchronized, neural-like response to acoustic click stimulation can be recorded from the cochlea (Aran et al., Acta Oto-Laryngol. 1979, in press). This response, which is sensitive to anoxia and masking, appears as soon as the normal compound auditory nerve action potential has disappeared, before the end of the treatment and then remains absolutely constant in time (over a 10 months follow up period). This response is followed by various activities in the central nervous system which are recorded and compared to that observed in similar conditions in normal guinea pigs. [Work supported by INSERM grant No. 8-ASR-6.]
Permeability of the cochlear partition assessed by electrochemical potential changes during anoxia
Authors: Konishi T. , Salt A. N.
Published: October 2005

We reported that ionic permeability changes in the endolymph-perilymph barrier contribute a significant factor in the physiological mechanisms underlying the noise-induced hearing loss (J. Acoust. Soc. Am. 64, S132 (1978)]. An indirect method of estimating permeability changes is to measure alterations of electrochemical potentials during anoxia, from which the contribution of passive ion movement can be calculated. This allows differences of permeability of the endolymph-perilymph barrier between normal and noise exposed guinea pigs to be indirectly assessed. The endocochlear potential (EP) and K+ concentrations of endolymph and perilymph were simultaneously measured in the basal turn of the guinea pig cochlea with a pair of double barreled K+ selective electrodes. When anoxia was induced in guinea pigs treated with dihydrostreptomycin, the rate of decline of both EP and chemical potential for K+ was reduced compared with normal animals. In guinea pig exposed to broad band noise at 115 dBA for periods ranging from 3 to 17 days, initial results indicate that the decline of the electrochemical potential is reduced but not to the extent found in dihydrostreptomycin treated animals. Results of analysis on electrochemical potential changes in noise exposed guinea pig cochlea during anoxia will be presented.
Optimal stimuli for cochlear outer dendrites
Authors: Winslow J. L. , Outerbridge J. S.
Published: October 2005

To distinguish the functional difference of the two types of cochlear dendrites, simulation studies were done to discern the AP generating site response for different sound input signals. An outer dendrite receives synaptic input from hair cells that cover 200 microns on the cochlear partition, which is associated with optimal sound input frequency per location on the partition. The synaptic boundary condition is V(0,t) = g(t) * (V(0,t) + K) with synaptic conductance g(t), intra-extracellular equilibrium potential difference K, and V(x,t) denotes dendrite response potential at location x, time t. The nonlinear boundary condition and nonsimple geometry rule out closed form solutions for the dendrite partial differential equation. Simulations were done to examine AP generating site responses. Preserving the geometry,compartmentalization yielded a set of ordinary differential equations with rate constants differing by several orders of magnitude, which have instabilities when solved by usual numerical integration techniques. The set becomes integrable when using methods for stiff differential equations. In descending order of response effectiveness, best inputs are: all synapses active (frequency band sound input), basal to apical synapses active (frequency downsweeps), and apical to basal synapses active (upsweeps).
Appropriateness of different rule types in speech synthesis
Authors: Hertz Sue
Published: October 2005

The Cornell Speech Research System has been augmented to support a third kind of rule. In addition to feature and parameter rules, the user can now express letter-to-sound rules. Feature rules modify the feature composition of an utterance, and parameter rules transform the output of the feature rules into a file of synthesizer parameters. Letter-to-sound rules convert standard orthography into a phonetic transcription. A powerful notation has been developed for expressing these rules. By using the system, we have found that the three kinds of rules can be written to interact in linguistically meaningful ways to yield speech.
A statistical vowel labeling technique
Authors: Tai Wallace
Published: October 2005

A vowel normalization technique based on the statistics of interrepetition variation by a single speaker has been implemented as part of the acoustic-phonetic analysis component of an SDC speech analysis/synthesis system. Since the statistics of interrepetition variation are represented by normal distribution [D. Broad, Phonetica 33, (1976)], a frequency-domain vowel normalization table can be constructed over each of the first three formant frequencies for the same speaker. The frequency range within which a vowel has the highest probability can be defined by calculating the intersections of the normal probability density functions of this vowel and its “adjacent” vowels. The probability for the vowel with the formant frequency falling outside the most probable range but within the normal distribution boundaries can then be obtained. Therefore, for each frequency interval, three or four vowel choices and their probabilities are included in the frequency-domain vowel table. For labeling an unknown vowel segment with steady-state formant frequencies, the candidate with the highest probability in the related formant interval is considered to be the best choice. Although more training sessions are required, an advantage of this labeling method over the traditional nearest-neighbor method where the linear distance between the formant frequencies of the unknown and the prestored targets are calculated, is its faster speed in a real-time environment because the number of computations is less. The study is also useful in testing the sensitivity to interrepetition variation of an analyzer which uses the nearest-neighbor method. Labeling results based on the statistical method and the nearest-neighbor method are compared for five male speakers. [Work supported by RADC.]
Trainable grammars for speech recognition
Authors: Baker J. K.
Published: October 2005

Algorithms which are based on modeling speech as a finite-state, hidden Markov process have been very successful in recent years. This paper presents a generalization of these algorithms to certain denumerable-state, hidden Markov processes. This algorithm permits automatic training of the stochastic analog of an arbitrary context free grammar. In particular, in contrast to many grammatical inference methods, the new algorithm allows the grammar to have an arbitrary degree of ambiguity. Since natural language is often syntactically ambiguous, it is necessary for the grammatical inference algorithm to allow for this ambiguity. Furthermore, allowing ambiguity in the grammar allows errors in the recognition process to be explicitly modeled in the grammar rather than added as an extra component.
Talker-independent speech recognition in commercial environments
Authors: Moshier S.
Published: October 2005

A machine which performs long distance voice telephone dialing and charge account verification for 4000 civil service employees of the State of Illinois was installed in April 1978. This and similar installations now perform routine daily services for thousands of users. An overview of the development of this system is presented, including discussion of human factors studies, computer engineering, voice data base development, software operating systems, and the speech recognition method per se.
Temporal resolution in normal and hearing-impaired listeners
Authors: Fitzgibbons Peter J. , Wightman Frederic L.
Published: October 2005

Temporal resolution, defined as the minimum detectable temporal gap (Δt ms) separating equal intensity noise bursts, was investigated with normal-hearing and cochlear-impaired listeners. In separate conditions, octave-band noise signals of 400–800 Hz, 800–1600 Hz, and 2000–4000 Hz were presented against a background of band-reject broad spectrum noise designed to eliminate the influence of spectral artifact in threshold measures. Gap resolution for both listener groups showed systematic improvement with increased signal frequency, though performance of hearing-impaired subjects was significantly poorer than normal at each octave-band region. These findings were evident for listener group comparisons made on the basis of both equivalent sound-pressure-level and sensation-level signal intensities. Results are compared to previous gap resolution estimates reported for wide-band stimuli, and are discussed in terms of peripheral filter mechanisms thought to influence resolution performance. Implications for temporal processing in the presence of cochlear damage are also considered. [Work supported by NIH Grant No. NS12045.]
Short and long term effects of commissurotomy on selected tests of central auditory function
Authors: Musiek Frank E. , Wilson Donald
Published: October 2005

A 19-year-old male, with normal peripheral hearing, was administered various central auditory tests prior to a complete commissurotomy. Testing was also done in one and one half weeks and one year after the commissurotomy. The test battery included speech in noise (+5 S/N), dichotic digits, the SSW (staggered spondaic word) test, and intensity and frequency pattern perception tests. Initial postoperative testing showed little change in performance on the speech in noise task. However, results for the dichotic tests (SSW and digits) showed a dramatic left ear decrease. Results from the two pattern perception tests showed a marked decrease in performance for both ears [e.g., Musiek, Pinheiro and Wilson, J. Acoust. Soc. Am. 63, S31(A) (1978)]. Assessment approximately one year after surgery showed results consistent with initial postoperative testing for speech in noise and both pattern perception tests. However, both dichotic tests showed an improvement for left ear performance. The underlying reasons for this change at this time are speculative. However, the development of certain perceptual strategies and/or the improvement of neurological function over a certain period of time are considerations.
Speaking clearly for the hard of hearing
Authors: Picheny M. A. , Durlach N. I.
Published: October 2005

It is obvious that the intelligibility of a given speech message depends strongly on how the message is spoken. Not only does intelligibility vary with the identity of the speaker, but also, for a given speaker, with the effort to speak clearly. Assuming that the variations in intelligibility associated with such factors are substantial, detailed knowledge of these factors could prove useful in the development of improved signal-processing schemes for hearing aids. Our initial goal is to estimate the magnitude of the intelligibility changes associated with a given speaker's attempt to speak clearly. Among the variables to be considered are presentation level of material, frequency-gain characteristic of amplification system, severity of hearing loss, identity of speaker, and degree of familiarity with speaker's voice. Preliminary results obtained using sentence material for a number of hearing-impaired listeners will be presented. [Work supported by NIH.]
Perception of amplitude-compressed speech by impaired listeners
Authors: Peterson P. M.
Published: October 2005

CV syllable identification by practiced hearing-impaired listeners was compared for amplitude-compressed and linearly amplified speech. The amplitude-compression system (a 16-channel syllabic compressor) and the linear-amplification system were configured according to previously determined procedures [R. P. Lippmann, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 62, S90(A) (1977)]. Subjects were trained for about 30 hours to identify syllables presented at random from a set of 576 stimuli representing 24 consonants, three vowels, four speakers, and two utterances. Performance after training indicated no advantage in compression for moderate hearing loss, consistent with Lippmann's results. In the case of a severe flat loss, however, a small advantage was observed for compressed speech. Some confusions in identification were specific to the type of processing, although general patterns of confusion were roughly similar for compressed and linear speech. All confusions were further analyzed in terms of articulatory features and prominent confusions were examined more closely using a discrimination paradigm. [Work supported by NIH and NSE.]
Perceptual confusions of vowels and consonants through Tadoma
Authors: Reed C. M. , Rubin S. I. , Durlach N. I. , Braida L. C.
Published: October 2005

A study of the identification of vowels and consonants through the Tadoma method of speechreading was conducted for a deaf-blind user of Tadoma and for two normal subjects. Fifteen vowels and diphthongs, presented medially in a CVC context, and 24 consonants, presented in CVC syllables, were studied. The two normal subjects, who were blindfolded and exposed to masking noise, received approximately 75 h of training on vowels and 100 h of training on consonants prior to testing. An average score of roughly 60% was obtained for both vowels and consonants by the experienced Tadoma user, while scores for the normal subjects averaged roughly 80% for both types of stimuli. Feature analyses of the confusion matrices for vowels indicate that among the important perceptual features are those related to diphthongization, rounding, and tenseness. For consonants, the salient features include voicing, rounding, and frication. Results will be compared to those obtained in studies of lipreading. [Work supported by the Edith E. Sturgis Foundation and by NIH.]
Signal and noise sensitivities of fiber optic transducers
Authors: Africk S. A. , Jameson P. W. , Rudd M. J.
Published: October 2005

Fiber optic hydrophones offer potentially significant improvements in sensitivity, versatility, ruggedness, and reliability over conventional transducers. Calculations based on the assumption that a fiber optic hydrophone is quantum noise limited show promise for an excellent signal to noise ratio. However, in practice other noise sources, arising from the inherent sensitivity of a fiber to vibration and nonacoustic pressures, may dominate and prevent a fiber optic sensor system from operating at its quantum limit. Estimates of vibration sensitivity for a raw fiber indicate an equivalent self-noise about 100 dB above this limit at 1 g. Transduction of nonacoustic pressures within structures containing optical elements will take place. Because this will occur over an extended aperture, this contribution to self-noise will be smaller than that of a point sensor. Noise mechanisms due to undesirable mechanical interactions between the fibers and the nonacoustic pressure fields (e.g., the generation of free waves within the fiber) may be important. Similarly, the acoustic sensitivity of a fiber optic transducer may depend on the details of its construction and incorporation into a structure. Certain well designed configurations are expected to yield enhanced signal sensitivity and signal to noise ratio.
Discrete amplitude shading for sidelobe suppression of sources
Authors: Martin G. E.
Published: October 2005

Amplitude shading techniques are used in arrays to achieve reduced sidelobe levels with reasonably small major lobe width. Most papers on shading consider arrays without restriction of amplitude and location of the shading function to discrete choices. For some arrays such as resonant sonar arrays, it is desirable to achieve the amplitude shading by series-parallel combinations of discrete elements of the array. Such an arrangement forces a relationship between the width and amplitude of discrete zones. This problem is illustrated in the design of a linear array of 24 elements for which the sidelobe level must be less than −20 dB. One discrete shading configuration had −21.9 dB sidelobe level. The best choice of series-parallel combinations achieved a narrower beamwidth and a −25.7 dB sidelobe level. [Work supported by Naval Sea Systems Command.]
Characteristics of impulse noise produced by some industrial sources
Authors: Moreland J. B.
Published: October 2005

The time-domain description of impulsive noise found in industrial environments typically resembles exponentially decaying random noise. The peak sound pressure level (SPL) experienced by the operators of power presses and drop forges generally exceed 100 dB and, in some instances, exceed 150 dB. The B duration of the impulsive noise produced by these machines ranges from hundredths of a second to a few seconds, and is somewhat dependent on the distance and direction between the machine and the point of observation. Longer B durations are associated with the greater distances from the machine owing to reverberations. Power circuit breakers can be categorized into three classes in terms of their peak SPL, namely oil, SF6, and air blast. Oil circuit breakers generally produce a lower peak SPL than do the SF6 breakers which, in turn, produce a lower peak SPL than do air blast breakers. The B durations of the impulsive sounds produced by power circuit breakers is typically 115 ms for air blast breakers, 190 ms for the oil circuit breakers and 240 ms for SF6 circuit breakers. The reduction of peak SPL with distance generally follows spherical divergence out to about 1200 ft when propragating inside the switching yard.
Spectrum as a factor in rating the hazard from intense acoustic transients
Authors: Price G. Richard
Published: October 2005

It is generally agreed that the ear is spectrally tuned; yet neither of the two damage-risk criteria (DRC) for impulse noise in use in the world today specifically takes spectrum into account. At a recent meeting of the Acoustical Society an analysis was presented, based on the combined responses of the inner, middle, and external ears, which produced a curve showing the relative hazard from impulses with spectral peaks in various locations [G. R. Price, J. Acoust. Soc. Am. 62, S95(A) (1977)]. This approach has been carried further, and when coupled with the concept of a critical level for intense stimulation, has led to a new form for a DRC for impulse noise. This formulation rates the hazard differently than the previous DRCs and appears to be in consonance with the available data on hearing changes from impulsive stimulation. It is formulated so that the risk to varying proportions of the population for varying numbers of impulses can be rated, as well as the effectiveness of various hearing protectors. This analysis also generates a rationale for rating the hazard from stimulation below 130 to 140 dB SPL according to a different rule.
Annoyance criteria for impulsive noise sources from electric utilities
Authors: Hedeen R. A. , Norman R. S. , Teplitsky A. M.
Published: October 2005

Electric utility safety devices product intermittent, high noise levels when operating during emergency conditions. Community reactions to transient noise are developed here for the following two specific classes of safety device, based on information available in the technical literature: safety valves and 345 kV air-blast circuit breakers. Steam safety valves operate for several seconds up to 30 min and emit sound levels of 140 to 150 dBA at 1 m. Air-blast circuit breakers emit high impulsive noise levels (140 to 160 dB at 1 m) for less than 1 s. The day-night sound level (Ldn), has been selected as the basic sound descriptor for determining community reaction. The expected community reactions are presented in this paper in a series of graphs and charts. Several parameters used in the preparation of these displays are: type of source, duration, sound level, distance, ambient noise, and nighttime effects. The criteria are based on the day-night sound levels experienced by the affected population. Noise levels emitted by safety devices, after correction for discrete tones and impulses, are integrated into the ambient community day-night sound level with the aid of charts and formulae presented in the report. Community response to the intrusive noise is represented as a function of the difference between community day-night sound levels (ΔLdn) with the sources operating and not operating.
Problems in using the C-weighted day/night level to assess military blast noise environments
Authors: Luz George A. , Lewis Nelson D.
Published: October 2005

In recent papers [P. D. Schomer, J. Acoust. Soc. Am. 64, 1627–1632 (1978) and P. D. Schomer, J. Acoust. Soc. Am. 62, 396–399 (1977)], the author reanalyzed the psychoacoustic data on the annoyance of blast noise to support the use of the US Environmental Protection Agency's blast noise methodology, the C-weighted day/night level (LCdn), and to prove that the annoyance caused by a LCdn and an A-weighted Ldn of equal magnitude are equivalent. An analysis of the original psychoacoustic data and the recent papers by Dr. Schomer has lead to the conclusion that the two descriptors do not cause equal annoyance. A simple relationship has been derived to equate the two descriptors on an equal annoyance basis. Several statistical distributions of blast noise will be compared to demonstrate the differences in assessment that would result from the application of the US Environmental Protection Agency's methodology, the implied revision, and the relationship derived by the authors of this paper.
Devoicing of word-final stops
Authors: Parker F.
Published: October 2005

A process devoicing stops in word-final position is common among languages and is evidenced in Appalachian and Black English. Attempts to explain this phenomenon, however, have been unsuccessful. For example, generative phonology, which accounts for change by rule-addition, rule-loss, and rule-reordering, is purely descriptive. Likewise, natural phonology, which claims that change occurs when a child fails to master a phonetic opposition, never explains under what conditions “failure” occurs. Instead, devoicing may be explained in terms of the voicing cues for post-vocalic stops. (1) Voicing is signalled by the manner in which the preceding vowel is terminated. (Termination is defined in terms of the period of vocal cord vibration during the transition from vowel to stop.) [F. Parker, J. Phonetics 2, 211–221 (1974).] (2) The cue for a post-vocalic voiced stop is perceptually weaker than that for its voiceless counterpart. (Evidence comes from error detection studies and phonological change.) Thus, devoicing represents a strategy by which speakers maintain the integrity of the speech signal. This makes sense, because the processes of production and perception are at odds: encoding processes reduce acoustic differences between consonants and vowels, while decoding requirements force consonants and vowels to be kept distinct.
Sonorant-fricative clusters in English
Authors: Fourakis M. S.
Published: October 2005

Several phonologists have claimed that the insertion of a stop between a sonorant and a fricative consonant in syllable final sonorant-fricative consonant clusters follows from universal constraints on the human speech production and perception mechanism. In our experiment five speakers each of American and South African English read a list of real and nonsense words ending in clusters of [n] or [l] plus [s] or [ts] and their voiced counterparts. The duration of the stressed vowel and each measurable cluster segment was measured from spectrograms. Preliminary results suggest that (1) South African speakers maintain the contrast between sonorant-fricative and sonorant-stop-fricative clusters (tense versus tents) yet keep total syllable duration constant. (2) Voicing of the final fricative (tens) blocks the insertion of the stop in the speech of the American speakers, while (3) those speakers who insert a stop before /s/ (neutralizing /ns/ and /nts/) lengthen the total duration of the syllable. Results imply that stop insertion is a language specific process that can be implemented in several ways.
Dimensions of tone systems
Authors: Maddieson Ian
Published: October 2005

Reliable data on tone systems has been assembled through a survey of a large sample of tone languages. Simple two-tone systems are the most frequent; added tones reduce the frequency of occurrence. While two- and three-tone systems generally have only level tones, both level and contour tones are commonly included in four-tone systems. Five-tone systems generally include level, rising and falling tones, while contours that move in the same direction but differ in the amount of pitch change are typically found only in large tone inventories. Thus, the commonest inventories exploit only contrasts of pitch level, larger inventories add contrasts on a dimension of direction of movement, and only the most elaborate and least common inventories are likely to use contrasts of amount of change. These dimensions correspond in ranking with the cognate perceptual dimensions of average pitch, direction, and slope found by Gandour and Harshman [Lang. Speech 21, 1–33 (1978)]. Here the ranking implies, roughly, that subjects relied most on the average pitch dimension to discriminate between tones, then next they relied on the direction dimension, and so on. The correspondence between the two rankings suggests that tone inventories are elaborated by recruiting progressively less salient perceptual dimensions.
The pitch contour in WH-questions
Authors: Waibel A.
Published: October 2005

The fundamental frequency (F0) contour of WH-questions was investigated in three experiments. In experiment 1, WH-questions were compared in context and in isolation. On the last content word of a WH-question in context, higher peaks and steeper slopes on the fall-rise pattern were found. No significant difference was measured for the WH-word. In experiment 2, F0 declination lines were compared for pairs of sentences with high phonetic similarities, one being a WH-question, the other a declarative sentence. The slopes were seen to be significantly steeper for the WH-question than for the declaratives. Although the slopes differ for sentences in context and isolation, significance tests suggest that this is not an effect due to the questioning or declarative nature of the sentence. In summary, it has been seen that a steeper declination line is a distinguishing feature of WH-questions as opposed to declaratives, while prominent fall-rise patterns appear to serve semantic purposes. Measurements to establish the source of these differences and to investigate their necessity for discrimination are being examined in the third experiment using synthetic speech for listening tests.
Some temporal aspects of spoken discourse
Authors: Lehiste Ilse
Published: October 2005

A sixteen-minute “prompted monologue” was produced spontaneously by a male native speaker of English. The last five minutes, during which the speaker spoke without interruption by the prompter, were used for a listening test. Twenty-five subjects heard a filtered version and an undistorted version of the material, and indicated their perception of sentence and paragraph boundaries by pressing a telegraph key. The percent pre-boundary lengthening was calculated for perceived sentence and paragraph boundaries within the uninterrupted “turn” as well as for the boundaries of “turns”. The average pre-boundary lengthening for sentence boundaries and paragraph boundaries within the uninterrupted five-minute “turn” was 34.0% and 34.4% respectively, while the pre-boundary lengthening before the end of a “turn” averaged 42.9%. Pauses between sentences averaged 737 ms, those between paragraphs, 1659 ms, and those between “turns”, 5045 ms. While the difference between paragraph terminations and “turn” terminations could be explained on the basis of pause duration as well as difference in degree of lengthening, other factors enter the picture as far as the distinction between sentence and paragraph boundaries within a “turn” is concerned.
Rhythmic constraints on children's speech: Data for 3 to 6 year olds
Authors: Allen George D. , Hawkins Sarah , Morris Margaret R.
Published: October 2005

Young children vary widely in the degree to which their words agree with the adult form in number of syllables or stress pattern. Children's alterations frequently involve the deletion of weak syllables, usually in pretonic position (e.g., /'nænə/ for banana). Because rising-accent forms (e.g., lambs like/bə'næn/) rarely occur, we hypothesized that English-speaking children “prefer” falling-accent forms (e.g., trochees); this paper describes an experiment designed to test that hypothesis. Three- to six-year-old children learned to associate three pairs of toys differing only in color with three pairs of names differing only in accent contour (e.g.,/'ta,ki/ vs/,ta'ki/). After association learning, the names were elicited from the children and tape recorded for phonetic and acoustic analysis. Pilot data show that the rhythmic forms these children produced varied widely. Younger children often use only one form for both names, with no clear preference to date among falling, rising or level accent. Older children show a variety of error patterns, most often biased towards falling accent. [Supported by NSF and UNC Faculty Research Council.].
Intrinsic vowel duration and formant frequencies: Data from speech acquisition
Authors: Lieberman Philip , Kubaska Cathy
Published: October 2005

The vowels of American English are specified by particular formant frequency patterns and durations. Acoustic data derived from the speech of children between the ages of 69 and 145 weeks show that the vowels that they produce in meaningful words often have mismatched formant frequency patterns and durations. The formant frequency pattern of an intended [i], for example, may have the duration of an [1]. Psychoacoustic experiments using computer edited stimuli derived from the children's vowel productions demonstrate the interaction of formant frequency patterns and duration as acoustic cues to vowel perception. Intrinsic vowel duration and control of the supralaryngeal vocal tract appear to be independent parameters in the acquisition of speech. Hypothetical phonetic features like Tenseness thus can not be causally linked to relative vowel duration.