bluuebunny/crossref_metadata_2025 huggingface dataset:
Contextual factors influencing tone discrimination
Authors: Hombert J. M. , Greenberg S.
Published: October 2005

Studies by Ohala and Ewan (1973) and Sundberg (1973) suggest that asymmetries found in tone languages (e.g., falling tones are more numerous than rising tones) may be related to constraints imposed by laryngeal displacements. These articulatory constraints may be reinforced by limitations on the auditory system's ability to perform accurate frequency discrimination. This study investigated the manner in which the pitch of one linguistic segment can affect the pitch of its neighbor. The stimuli consisted of synthesized V1CV2 sequences onto which were superimposed two fundamental frequency contours: high-low or low-high (high = 150 Hz, low = 120 Hz). Subjects were asked in one condition to indicate whether the pitch of a steady-state vowel following the stimulus was higher or lower than the pitch of V1. In the other condition, judgments were made with respect to V2. The fundamental frequency of the comparison vowels ranged from 10 Hz below to 10 Hz above the F0 of the target vowel. The data reveal the extent to which discrimination of a linguistic segment's tone is adversely affected by a following (higher) or preceding (lower) tone.
Very early expectancy effects in continuous speech perception
Authors: Martin J. G.
Published: October 2005

In experiments measuring reaction time (RT) to a phoneme target carried in sentences, earlier work in our laboratory has shown that RT is slower when the target is temporally displaced by experimental intervention, e.g., artificially adding 100 or 200 msec of silence to a pre-stop-consonant silent interval two syllables earlier in the sentence. The result was interpreted in terms of disrupted timing expectancies. On the other hand, target RT was faster if the artificially extended silence immediately preceded the target, presumably because that experimental intervention in effect provided the listener with coarticulatory target cues in advance, compared to the normal sentence version. Experiments to be reported show these opposite RT results based on disrupted timing vs coarticulatory cue effects occur when the pretarget intervention is located between the first and second syllable of the sentence. These results and others indicate an interaction between segmental and suprasegmental cue effects and dynamic feed forward processing continuous speech perception. [Work supported by NIMH.]
Perception of speech segments: Parallel processing of sequentially presented syllables
Authors: Streeter L. A. , Landauer T. K. , Ross B. H.
Published: October 2005

Artificial words (/pətə/, /pəbə/, /dətə/, and /dəbə/) were presented with the sound level of the first, second, both, or neither syllable attenuated by 30 dB. Reaction times to identify the words increased if either the first or second syllable along was attenuated. However, if the second syllable was attenuated, also attenuating the first caused no additional increase in identification time. These results appear to exclude a model of serial processing in which the identification of the first syllable is completed before the identification of the second is initiated. They are consistent with a process in which syllables are discriminated independently and in parallel with the time for the word determined by whichever syllable's identification is completed last.
Effect of two-dimensional configurations on the identification of associated vowel sounds
Authors: Miller J. E. , Fujimura O. , Campbell H. W. , Kruskal J.
Published: October 2005

A computerized two-dimensional “sort board” is described which allows for the sorting or rank ordering of acoustic stimuli. It features light buttons on a CRT display, which when selected result in the presentation of auditory stimuli. The positions of the buttons can then be moved on the screen by use of a light pen. The study of vowel perception to be reported consists of an experiment in which a given configuration of buttons is displayed on the CRT and a sequence of vowel sounds is presented to the subject in random order. His task on each trial is to point to the button he thinks corresponds to the sound. A flashing of the correct button reinforces his response as right or wrong. His performance is then evaluated in terms of response time and errors. The question under investigation is the significance and effect of a particular spatial arrangement of the stimuli upon his ability to remember correctly and respond quickly in making the identifications.
Frigidity or feature detectors—slips of the ear
Authors: Browman Catherine P.
Published: October 2005

Mistakes in the perceptual process can indicate some of the mechanisms involved in perception. Naturally occurring misperceptions, or “slips of the ear,” are an important source of errors. In this study, over 100 misperceptions were collected by the author and others. The errors are categorized in terms of phonemic similarity and location with respect to possible unit boundaries, such as word and syllable boundaries. Word boundary misperceptions in particular frequently occur—for example, “frigidity” heard for “feature detectors” spoken.
“Co-perception” of speech segments
Authors: Repp B. H.
Published: October 2005

A definition of “co-perception” is proposed, in analogy to the definition of coarticulation: Co-perception is said to exist whenever the perception of a (phonetically defined) speech segment is influenced by a preceding or following segment. The measure of co-perception is the reaction time (in “same-different” judgments, speeded classification, or monitoring) to a certain well-defined segment, while other segments vary systematically. Three hypotheses to explain co-perception are discussed: (1) A temporal integration period (or limited buffer memory) in speech perception; (2) genuine functional analogies to coarticulation; and (3) “phonetic coherence” factors, such as the primacy of the CV syllable. These hypotheses may be investigated by appropriate variation of the phonetic composition and the temporal parameters of the speech stimuli used. Some experimental paradigms are discussed, and preliminary data are reported that demonstrate co-perception of consonants and vowels in CV, VCV, and (perhaps) VC syllables.
Some acoustic characteristics of syllable nuclei in conversional speech
Authors: Earle M. A. , Pfeifer L. L.
Published: October 2005

Approximately 5 min of conversional speech from an interview of one male speaker of Midwestern American was transcribed and digitized. The digitized speech is bandlimited at 5 kHz, sampled at 10 kHz, and quantized to 12 bits per sample. Steady-state portions of the vowels and initial and final portions of the diphthongs are located by visual inspection of a time-synchronized display of the waveform, spectral peaks, and the rms of the signal. Formant parameters derived from the inverse filter method of linear prediction are then extracted from four consecutive spectral samples representing 29.6 msec of the steady state of each vowel or of the most stable region in the initial and final portions of each diphthong. The effect of various segmental environments on some acoustic parameters, such as formant frequencies, is discussed. A comparison is made of the vowel and diphthong samples in terms of formant frequency means and standard deviations. [This research is supported by the Air Force Office of Scientific Research under Contract F44620-74-C-0034.]
Vocal tract excitation during voicing and its relation to optimal short-time frequency analysis of speech
Authors: Heironymus James L.
Published: October 2005

The physics of vocal tract excitation during voicing is presented with emphasis on the transient nature of the excitation. The vocal tract is excited by a delta function like impulse at the time of the closing of the glottis. After reflecting from the mouth opening the impulse excites standing modes in the vocal tract. Knowledge of this time sequence leads to some conclusions about the best interval in which to analyze the signal. The optimal time window for obtaining articulator positional information includes only the ringing portion of the time waveform and exclude the excitation pulse. Therefore this optimal frequency analysis is a type of pitch synchronous analysis. Detailed comparisons with other types of short-time frequency analysis are made, including the sound spectrograph, and autocorrelation method of linear predictive coding. Pitch synchronous analysis is shown to be closely related to broadband sound spectrograms, while autocorrelation linear predictive spectra are related to narrow-band sound spectrograms, in the case of optimal spectra, the resonant frequencies of the vocal tract are so clearly defined that formants may be easily obtained by peak picking. Since the formants are obtained each pitch period, rapid transitions are followed in greatest possible detail.
Community noise countermeasure cost-effectiveness analysis
Authors: Rackl R. , Sutherland L. , Swing J.
Published: October 2005

An analytical model of a typical community has been developed for the purpose of carrying out a cost-effectiveness analysis of various outdoor noise countermeasures. The principal elements of the model are (1) a data base describing the community's geography, population distribution, and typical building construction: (2) a data base describing the location and strength of noise sources; (3) energy summation of noise levels from each source at many locations; and (4) use of noise level versus human response transfer functions to determine the number of people adversely affected by noise level. Summing these for the whole community and dividing by the total population results in a “Noise Impact Index (NII)” indicating the quality of the noise environment. Three basic types of countermeasures may be applied: (1) source reduction, (2) source rerouting, and (3) path-receiver treatments (increased building attenuation, relocate people). Each countermeasure is also defined in terms of the corresponding costs to achieve varying amounts of noise level reduction. Given a maximum amount of total funds available, the model can then be applied to distribute these funds over the countermeasures in such a way as to minimize NII. Results for a statistically average U.S. city (Spokane, WA) show that source reduction of surface transformation vehicles is most cost-effective followed by aircraft source reduction. Increasing residential building attenuation becomes cost-effective only at very high levels of total funds available. Moving people away from noise sources has not appeared as a viable alternative in the analyses conducted so far. Further work is needed for the results of the model to be more generally applicable. [Program supported by the Motor Vehicle Manufactures Association.]
Beam pattern synthesis and the curved line array
Authors: Wallace R. H.
Published: October 2005

The synthesis of beam patterns formed by plane arrays has been developed by Tucker, Morris and Hard, and others. This paper extends the work to include the use of a curved line radiator in forming wide beams with selected characteristics. The linear superposition of narrow beams whose shape is closely approximated by the equation sin(x)/x is used to form the desired wide beam. Good results have also been achieved with the linear superposition of narrow shaded beams. In this work, emphasis has been placed on amplitude uniformity across the main beam and with reduction of the amplitude of the lobe structure outside the main beam. Analytical data are presented to demonstrate that wide beams with uniform amplitude across the main beam and with low minor lobe structure may be achieved in this manner. In addition, it is shown that with symmetry and proper shading, all of the elements in the array may be driven in phase. Experimental data in good agreement with the analytical data are shown to support the analytical part of the study and to demonstrate that almost constant beamwidth over a wide frequency band may be achieved just as with the plane array.
Proposition of a damage-risk-number for hearing conservation purpose
Authors: Groenewold F.
Published: October 2005

Standards dealing with hearing impairment due to noise exposure define “risk” in an ambiguous and not quantitative way. (See, for example, ISO/R 1999–1971, p. 6.) These definitions have been thrown on from statistical methods and involve by themselves computational procedures. In the proposition, presented here, it is suggested as a single number, a function of the variables, noise level, exposure period, personal sensibility, age, work period, previous experience, previous hearing damage, and clinical illness tendency. Function is developed with statistical procedures, according population distribution, and individual characteristics. Number is given in percent, but can be used in decimal form. The number will serve to qualify a worker fitness against noise in a certain task, to establish noise hazards to men in a certain industrial or urban zone, to determine exposure grade to traffic noise, to establish decision criterion to industrial noise control, or to fix premiums for insurance payment in case of a handicap or a loss of heating ability due to work.
Measuring source location in a steady state waveguide
Authors: Hinich Melvin J.
Published: October 2005

The signal-to-noise ratio of received radiation is enhanced by properly combining the output from a collection of sensors which are connected as an array. In an infinite homogeneous medium, such as a deep ocean layer, the array is matched to the incoming signal by adjusting the phases or time delays of the sensor output so that the signals may be added coherently. This technique, called beamforming, can be performed in either the time-space or the frequency-wave-number domain in order to estimate the source bearing. Beamforming, however, is inappropriate if the waveguide boundaries significantly affect the radiation field. The maximum-likelihood estimators of source bearing and depth are reviewed in this paper, and the results extended to the general problem of estimating the location of a source in a finite waveguide. The optimal array design for estimating source depth in an infinite, homogeneous, horizontal waveguide is shown to be horizontal, and thus a horizontal array can be used to obtain source depth as well as bearing in a shallow waveguide. When the waveguide is closed, the degrees of freedom of the noise is limited to M, the number of modes excited by the source. Thus there is no gain in signal-to-noise ratio by using more than M sensors in the array. The rose of the maximum likelihood estimator of source location is of the order of M−1.
360° symphonic concert halls and music pavilions
Authors: Jaffe C.
Published: October 2005

Historic background on the development of 360° concert halls and music pavilions. Applications of end-stage rectangular hall criteria to the circular form. Discussion of advantages in terms of musical acoustic listening criteria in the hall and on stage. Analysis and critique of completed facilities: Ontario Place; Concord Pavilion; and the Denver Center now under construction.
Investigation of the acoustical characteristics of fabric roof structures
Authors: Walsh David P. , Gilbert John C.
Published: October 2005

Fabric roof structures are becoming increasingly popular for enclosing large recreational facilities. These structures are relatively inexpensive to construct since material costs and construction time are significantly reduced. In addition, the fabrics used have been developed to last as long as regular roof coverings. However, Because of the curved geometries and high sound reflectivity of the fabric membrane under tension, serious acoustical problems can arise. There are basically two types of fabric roof structures being used today: (1) those employing a frame and/or cable superstructure to support the roof membrane (tent structures); and (2) those in which the fabric is supported by pressurizing the interior of the space (air structures). The latter type requires unconventional means for achieving acoustical control since the roof material must be lightweight to remain erect. Fabric structures of both types and of various sizes and uses were investigated. Reverberation time data were collected and absorption coefficients of the roof membranes calculated.
Incorporation of noise control in power plant design
Authors: Brittain F. H.
Published: October 2005

Increasing enforcement of OSHA (in-plant) noise exposure and community (property-line noise) regulation, imply that cost-effective noise control must be incorporated as part of the design process. Such a design can be expected to not only reduce potential problems with regulatory agencies and nearby residents but to result in a better engineered power plant. The need for and state-of-the-art power plant noise control is briefly reviewed. Engineering of a power plant can be broken into five phases: proposal, environmental assessment, preliminary engineering, detailed engineering, and start-up. Details of how and where to incorporate noise in plant design are given for each of these five phases of design. Further information regarding suggested noise control engineering personnel requirements and organization are also given.
Psychological and physiological acoustics: 1920–1940
Authors: Davis Hallowell
Published: October 2005

The 1920 decade was dominated by new and improved instrumentation and by the Bell Telephone Laboratory program that undertook to measure (physically) speech, hearing, music, noise, and (with E. P. Fowler, Sr.) abnormal hearing. It also introduced syllable articulation and sentence intelligibility tests. Harvey Fletcher summarized all this in Speech and Hearing in 1929. In 1928 Georg V. Békésy described the traveling wave pattern on the cochlear partition, and in 1930 E. G. Wever and C. W. Bray listened to the electrical output of a cat's auditory nerve. These events initiated a whole new era in the bioacoustics of the ear and the electrophysiology of the auditory system. Psychoacoustic topics of interest included masking, lateralization, combination tones, and subjective scales of pitch and loudness. The different approaches were correlated by S. S. Stevens and H. Davis in Hearing in 1938.
Comparison of two paradigms for measuring auditory temporal resolution
Authors: Smiarowski Richard A.
Published: October 2005

The minimum perceptible separation (Δt) between two successive bursts of broad-band noise has been used as a measure of auditory temporal resolution by Plomp [J. Acoust. Soc. Am. 36, 277–282 (1964)] and Smiarowski and Carhart [J. Acoust. Soc. Am. 57, 1169–1174 (1975)]. By varying the relative level of the trailing noise burst, these investigators provided information about the time course of temporal resolution. Smiarowski and Carhart acknowledged that their temporal resolution paradigm may have given the listener a cue to the presence of an interruption (Δt) as a result of increasing the total duration of the pair of bursts by an amount equal to the Δt. The present study was designed to determine whether this total-duration factor does indeed influence temporal-resolution data. To accomplish this, temporal resolution was measured with the Smiarowski-Carhart paradigm, and an additional paradigm that maintained the same total duration of the pair of noise bursts in both the interrupted and fused presentations. The data from this experiment did not reveal any systematic difference in the time course of temporal resolution when measured with the two paradigms. It appears that the magnitude of the residual activity, rather than total duration, is the basis of listener judgment in the Smiarowski-Carhart paradigm. This data has implications for auditory persistence and the related phenomenon of forward masking. [Supported by V.A. Medical Research Project 7990-01.]
Correlations between computer-averaged auditory evoked potential amplitudes and detection threshold levels in squirrel monkeys
Authors: Wilpizeski C. R. , Wick E. A.
Published: October 2005

Under the assumption that large evoked potential amplitudes and low detection levels both reflect keen auditory acuity, Pearson product moment correlation coefficients were computed at 8 audio frequencies (air or bone conducted tone bursts) from a group of adult (N=39) and a group of juvenile (N=15) otologically normal squirrel monkeys. Computer-averaged evoked responses were obtained under waking conditions from permanently implanted recording electrodes having tips located in peripheral auditory regions and on the surface of the brain cortex. Stimuli were delivered either through a TDH-39 earphone or a Radioear B79-A bone vibrator. Correlation coefficients were all negative and ranged from 0.12 to 0.79 with a grand mean of 0.49. Mean r's were higher for juvenile monkeys, for air-conducted stimuli, and for peripheral electrode locations. [Work supported by NIH.]
Spectral content of CM
Authors: Hubbard A. E. , Geisler C. D. , Mountain D. C.
Published: October 2005

CM was recorded from scale media in the first three turns of the guinea pig's cochlea using pure tone acoustic stimulation. Averaging followed by FFT analysis was used to obtain amplitude and phase of the harmonic components. The acoustic stimulus was fixed in frequency at about 120 Hz, and sound pressure level was varied from 0 to 120 dB SPL. As harmonics appeared above the noise level of 0.1 μV, their slope with respect to SPL was found to approximate N × 6 dB/octave, where N designates the number of the harmonic. At about the same SPL, all harmonics demonstrated saturation. At 120 dB SPL roughly 35 harmonics appeared above the noise level. The magnitude data supports a model in which a changing resistance is represented by a real-valued power function of basilar membrane motion. However, the observed relationships indicate that such a model is inadequate to explain CM generation. [Supported by NIH grant 1P1NS12732-01.]
On the singing of hydrofoils
Authors: Blake W. K. , Maga L. J. , Finkelstein G.
Published: October 2005

Flexural vibrations of hydrofoils can be caused by the formation of vortices at their trailing edges. These vortices are formed at a predominant frequency which depends on the water velocity and a characteristic transverse wake dimension. When the shedding frequency corresponds to a flexural resonance frequency of the hydrofoil the severe vibrations, called “singing,” occur. This paper is a discussion of new measurements designed to quantify the hydroelastic interactions which cause the phenomenon. The wake-induced pressure fluctuations generated on a streamlined strut have been measured in a wind tunnel. The frequency spectral content, the chordwise variation, and the spanwise coherence of the pressures have been obtained. The trailing edge of the strut was oscillated at varying amplitudes and over a range of frequencies relative to the natural vortex shedding frequency. Effects on the flow-induced pressures were observed. In a second series of measurements, flow-excited vibrations of simple hydrofoils have been measured in a water tunnel. The amplitude of vibration has been examined as functions of the chord and thickness of the strut, the internal damping, and the mode order of the hydrofoil. Measurements of wetted mass and total damping are used to deduce hydrodynamic forces for comparison to the wind-tunnel results. The application of some recent semiempirical prediction schemes will also be explored.
Brief auditory stereograms
Authors: Ahumada A. , Marken R.
Published: October 2005

Auditory analogs of Julesz' random-dot visual stereograms were created using 100-msec tone bursts as dot analogs and interaural phase shift as the analog of visual angle disparity. Noise bursts consisting of 500 simultaneous tone components with random phase were presented to one ear. The frequencies of the components ranged from 10 to 5000 Hz by 10-Hz steps. At the same time the other ear received an identical burst except that some components were phase shifted relative to the same frequency component in the other ear an amount corresponding to a 1-msec delay in one ear (figure components) and all others were phase shifted according to a 1 msec delay in the other ear (ground components). Surprisingly poor stereo resolution was obtained; only very broad band figures could be reliably resolved.
Detection of sinusoidally modulated interaural time differences
Authors: Wesley Grantham D. , Wightman Frederic L.
Published: October 2005

These experiments were designed to determine the capability of the binaural system to detect sinusoidally modulated interaural time differences. In the first experiments observers were required to discriminate sinusoidally frequency-modulated (FM) tones whose modulation frequencies were interaurally in phase (diotic) from the same FM tones with the modulation interaurally out of phase. In the latter stimulus the interaural temporal differences is a sinusoidal function of time. Several carrier frequencies were used. In another experiment the “carrier” was a low-pass noise constructed by adding pure tones. Each tone was frequency-modulated such that the interaural temporal difference at a given time was the same for all tones. In all experiments threshold amplitude (in μsec) required for discrimination was determined for several modulation frequencies. (At a modulation frequency of 0 Hz the experiment was a traditional Δt experiment.) The data are discussed in terms of the relative ability of the binaural system to detect a fluctuating interaural difference compared to its ability to detect a static difference.
Spectral response of miniature ultrasonic hydrophones
Authors: Harris G. R. , Herman B. A.
Published: October 2005

Miniature hydrophones can be used to determine the temporal and spatial characteristics of pulsed ultrasonic fields produced by diagnostic ultrasound equipment. Before temporal parameters, such as peak pressure or intensity, may be accurately known, however, the spectral response of the hydrophone and its effect on the incident broadband pulse must be determined. Commercial hydrophones presently in use consist of a piezoelectric ceramic disk with diameters ranging from 0.25 to 1 mm and resonant frequencies of from 10 to 20 MHz. Measurements have been made of the frequency response of several hydrophones over a 1–10-MHz range using both a continuous-wave and pulse technique. In the continuous-wave technique, a hydrophone is scanned across an ultrasonic beam in the far-field. The voltage output is squared and integrated to obtain a result proportional to power. This value is then compared to the measured beam power. The pulse techniques utilizes a broadband pulse whose spectral content is determined using a reciprocity technique. The response of the hydrophone is then determined by spectrum analysis of its output. In this presentation the spectral response of these hydrophones and its effect on the pulse measurements will be discussed.
Acoustic reflex threshold and loudness discomfort level relationships in normal hearing persons and persons with sensorineural hearing loss
Authors: Woodford C. M. , Holmes D. W.
Published: October 2005

Threshold of audibility, loudness discomfort level (LDL) and acoustic reflex threshold (ART) were obtained by the tracking method for normal hearing subjects, and subjects with sensorineural hearing loss. Stimuli consisted of wide-band noise and pure-tone frequencies of 0.5, 1, 2, 3, and 4 kHz. Stimulus duration was 200 msec with a 20-msec rise-fall time and 250-msec interstimulus interval. Loudness discomfort level was found to require at least 20 dB more intensity on the average than elicitation of the ART in normal hearing subjects. This difference in required intensity was reduced considerably in subjects with sensorineural hearing loss. In general, the difference in intensity required to reach LDL and ART was reduced as degree of hearing loss increased. In certain subjects the relationship was found to be completely reversed, i.e., LDL was obtained with signals less intense than those required to elicit ART. Some evidence supporting the use of LDL-ART comparison as a noise induced hearing loss susceptibility index will be presented based on a comparison of the LDL-ART relationship with noise exposure history.
Intensity discrimination in squirrel monkeys
Authors: Briggs R. , Harrison J. M.
Published: October 2005

It has been shown that discriminations of the positions of sound sources are immediately formed, i.e., that sound position is highly significant behaviorally [P. Downey and J. M. Harrison, J. Exp. Anal. Behavior 18, 433–463 (1972)]. Since sound sources always have position in addition to other characteristics, such as intensity, intensity discrimination may be interfered with by the more dominant discrimination of position. This limits both the kinds of stimuli and the conditions under which intensity discriminations can be formed. Squirrel monkeys were exposed to two sounds of different intensities and positions on each trial. Two response levers were available, each mounted contiguously with a speaker. When responding on the lever contiguous with the higher-intensity sound source was reinforced, an intensity discrimination was rapidly acquired (less than ten trials). When a response contiguous with the lower-intensity stimulus was reinforced, the discrimination was acquired with difficulty (over 800 trials). There was no interference by the formation of an initial stimulus position discrimination. The relation of response latency to stimulus intensity is most likely a significant factor in these findings and is currently being investigated. [Work supported by NSF.]
Observations on speech preparatory activity of the jaw in natural and compensatory speech
Authors: Hamlet S. L. , Stone M.
Published: October 2005

A number of investigators have noted that prior to speaking the articulators assume a speech-ready position, or preparatory set. Interpretations of the function of such preparatory activity vary, from cautious statements about it being a base from which speech gestures will be initiated, to postulation that a phonetically neutral position is assumed prior to speaking. We sought information on activity of the jaw, before initiation of a sentence spoken naturally, prior to the very first utterance after insertion of an experimental dental prosthesis, and prior to sentences spoken after a week of adaptation to the prosthesis. The prosthesis was an assymetrical type having 4 mm of thickness on the left side. We knew that some subjects made large jaw adjustments when speaking with this prosthesis and suspected that speech-preparatory activity might show some interesting characteristics also. Subjects speaking with wider excursions of the jaw after having adapted to the prosthesis were found to have wider-open preparatory jaw positions for those sentences. In addition, the preparatory jaw position was also wider open prior to uttering the very first sentence after inserting the prosthesis (when subjects had not yet heard how they would sound). Preparatory jaw positions correlated with the extent of jaw openness on vowels in the forthcoming sentences. [Work supported by NIDR.]
Discrimination and identification of synthetic speech by a child exhibiting voicing confusions in production
Authors: Bremer Christine D.
Published: October 2005

Tests of speech sound identification and discrimination were administered to a 512-year-old boy who substituted voiced for voiceless initial stops and /d/ for initial fricatives. Stimuli were taken from the Abramson-Lisker VOT series for bilabial, alveolar, and velar stops. Discrimination (as measured by a verbal “same”-“not the same” task) was well above chance for pairs of speech sounds which spanned the typically found voicing boundary for adult listeners. Identification (as measured by a previously trained picture-pointing task) was, however, random. Normal controls were near ceiling on both tasks. Three months later, following considerable improvement in the child's production of initial voiceless stops, identification tests were repeated. The child's identification had improved only to a level of approximately 65% correct. Possible reasons for the discrepancy between the child's levels of performance on the two types of tasks are discussed. [Work supported by NIH.]
Acoustical-perceptual correlates of the voicing distinction for initial stops and fricatives in esophageal speech
Authors: Ries J. E.
Published: October 2005

Tape recordings of nine esophageal and three normal speakers reading lists of stop- and fricative-initial consonant-vowel nonsense syllables were judged by eighteen listeners in a forced-choice intelligibility test. Esophageal stops and fricatives were significantly less intelligible than the normal productions. Error analysis of esophageal stops revealed 78.4% cognate voicing errors, the majority of errors occurring with voiceless stops. Measures of voice onset time (VOT) showed insufficient lag for the esophageal voiceless stops. In addition, post-burst aspiration was negligible for these voiceless stops. Burst amplitude was significantly higher for voiceless apical and velar stops than for their voiced cognates. Analysis of esophageal fricative errors revealed 59.2% cognate voicing errors. Proportion of voicing in steady state frication was calculated for all productions. Correct perception of voicing was found to be primarily a function of this measure. Using this proportion, 82% of the voicing judgments could be predicted. [This investigation was supported by NINCDS research grant no. NS 08041 and HRA predoctoral training grant no. MCT-000202-21-0.]
Respiratory volume and airflow characteristics of speech produced by deaf individuals
Authors: Itoh M. , Horii Y.
Published: October 2005

Respiratory volume and airflow characteristics associated with oral reading were examined for 12 females with profound hearing losses and 16 females with normal hearing. The deaf's results of respirometric analyses were further correlated with degree of hearing loss, overall speech proficiency, and breathiness. The results indicated that the deaf subjects as a group exhibited different speech breathing patterns in comparison with those of the normal-hearing subjects. The speech respiration of the deaf was characterized by (1) high air consumption manifested as high air expenditure per syllable, high average exhalatory airflow rates, and high peak airflow rates, (2) frequent inspirations, (3) inspirations at linguistically inappropriate places, (4) short duration of exhalation, and (5) sizable within-group variability. These characteristics of the deaf's speech respiration were especially prominent among the most profoundly deaf subjects. Correlational analyses revealed that more frequent breath taking during reading seemed to adversely affect overall speech proficiency while high air consumption was closely related to a breathy voice quality.
Comparison of classical plate theory, Timoshenko-Midlin plate theory, and exact elasticity theory for calculation of transmission loss through fluid-loaded plates
Authors: Young J. W.
Published: October 2005

Two approximate plate theories, “classical” (CP) and Timoshenko-Midlin (TM), are commonly used in computing radiation and scattering from submerged structures. These models have previously been compared with an exact elasticity theory calculation of the phase velocity of the first antisymmetric mode of an unloaded plate. On this basis, CP is limited to frequencies below 0.7 times critical for steel in water. No indication of the limitations of TM is, however, found by this calculation. A more appropriate problem for underwater applications is transmission loss through the plate. We have calculated this quantity versus frequency-thickness product and angle of incidence using both the plate models and the exact theory. This approach shows that CP agrees well up to 1.5 times critical frequency. TM correctly predicts the first and second flexural mode transmission peaks but fails in other ways at frequencies greater than 4.0 times critical. In particular, no effects of symmetric modes are included, and an incorrect limit is reached at grazing incidence.
Energetics of fluid loaded hull-like structures
Authors: Berkman E. F. , Smith P. W. , Kerwin E. M.
Published: October 2005

The spatial decay rate of vibratory response and of surface pressure for locally excited fluid-loaded ribbed plates is predicted and physically interpreted from the viewpoint of statistical energy analysis. Several canonical problem solutions are combined to yield a first order energetic model of the propagation of acoustic power along fluid loaded hull-like structures below critical frequency. These canonical problems are (1) damping of free flexural waves due to radiation from rib supports for periodically supported plates and (2) the hull grazing pressure field due to local excitation of a homogeneous plate. Comparison is made between analytic results and limited experimental data.
Model study of sound generation by hot jets ejecting into an augmenter tube
Authors: Vér István L. , Andersen Douglas W. , Grunnet James L.
Published: October 2005

To obtain baseline data, first the sound power spectrum of jet exiting from a nozzle of 2.5-in. throat diameter was measured with high accuracy as a function of the pressure ratio (up to 3) and temperature (up to 3300°F) utilizing the reverberation chamber method. Subsequently, the effect of augmeter tubes and subsonic diffusers on the noise generation process was investigated utilizing a test setup consisting of two adjacent reverberation chambers (burner room and exhaust room) connected to each other by the augmenter tube. The sound power was measured simultaneously in both rooms in order to evaluate both the change in total sound power output, and the split of the sound power between the burner room and exhaust rooms as a function of nozzle augmenter entrance distance for various ratios of the augmenter nozzle diameter. The paper will report the result of the acoustical and pumping performance tests. [This work was supported in part by the United States Navy, Southern Division Naval Facilities Engineering Command.]
Considerations in the estimation of glottal volume velocity waveforms
Authors: Markel J. D. , Wong D. Y.
Published: October 2005

Although numerous papers have been presented or published relating to the estimation of the glottal volume velocity waveform from speech, there is very little detailed information relating to the inherent limitations or accuracy of these procedures. When speech in an office environment is processed using reasonable quality microphones, tape recorders, analog to digital recording, and digital processing methods, the results are frequently disappointing [Holmes, J. Acoust. Soc. Am. 58, 747–749 (1975)]. The purpose of this paper is to describe several of the reasons why this disappointment occurs and to show how a combination of high quality direct recording into the computer and linear phase filtering, in conjunction with the covariance method at automatically derived anchor points, can result in theoretically expected glottal volume velocity waveforms for high intensity vowel sounds where glottal closure is known to occur. Timing relations with respect to the speech waveforms are also compared with other measures of glottal closure [Strube, J. Acoust. Soc. Am. 56, 1625–1629 (1974)].
Improvement of intelligibility and individuality of helium speech by use of autocorrelation function
Authors: Suzuki J. , Nakatsui M.
Published: October 2005

Helium speech is hardly intelligible owing to the expansion of speech spectrum F(ω). On the other hand, raising of the fundamental frequency F0 deteriorates the individuality and naturalness. Compression of F(ω) and F0 should be carried out in order to recover the intelligibility and individuality of helium speech. The compression ratio of F(ω), however, must be set greater than that of F0. Furthermore, it should be considered that helium speech is usually uttered in noisy environment. These problems are overcome by proposed method SPAC-H (Splicing of AutoCorrelation function of Helium speech). Short-time autocorrelation function ρ(τ) is calculated on input speech signal. A portion of period of ρ(τ) is segmented and expanded to the interval of new pitch period. It is essential to discard waveform arround τ=0. Compression of F(ω) and F0 is achieved independently in the waveform spliced from ρ(τ). Simulation of SPAC-H indicates that almost all of distortions of helium speech are corrected; i.e.,intelligibility and naturalness are recovered, speaker is easily identified, and the signal to noise ratio is improved.
Speech communication in packet-switched networks
Authors: Forgie J. W.
Published: October 2005

Unlike conventional circuit-switched communication systems, a packet-switched network provides communication paths among its customers which exhibit time-varying throughput and delay characteristics. To successfully communicate with speech through such a network the speech must be compressed to an average data rate which the network can almost always handle and a smoothing algorithm must be used at the receiver to eliminate most of the jitter in packet arrival times. The smoothing process introduces further delay in a communication system that inherently has greater delay than conventional circuit-switched systems. The tradeoff between delay and “glitches” caused by late arrival of packets suggests a compromise which allows some glitches (perhaps 1% to 2%). Recent experiments with the ARPANET, a network designed for data communication among computers, have demonstrated that successful speech communication can take place in a packet-switched network. [This work was sponsored by the Advanced Research Projects Agency of the Department of Defense.]
Core noise source diagnostics on a turbofan engine using correlation and coherence techniques
Authors: Karchmer Allen , Reshotko Meyer
Published: October 2005

A test program was conducted on a Lycoming YF-102 engine to identify sources of core noise. Specially constructed “semi-infinite” waveguide microphone probes were installed at various locations within the combustor and core nozzle. The pressure signals from the core nozzle resulted in the strongest correlation with microphone signals in the acoustic farfield. Between the combustor pressure signal and that of the farfield the shape of the cross-correlation function indicates a second time derivative relationship. This suggests that the combustion region is, in fact, a source region for core noise radiating to the farfield. This conclusion is drawn from a simplified model of Lighthill's acoustic analogy which indicates that there can be an acoustic contribution from a combustion region that is related to the second time derivative of the fluctuating entropy. Measurements of the pressure coherence function between various internal locations and the farfield appear to indicate the combustion contribution to the farfield noise from the YF-102 engine is confined to frequencies less than about 200 Hz.
Sensitivity and directivity of piezoceramic tubes with capped or shielded ends
Authors: Trott W. James
Published: October 2005

The electroacoustic sensitivity of cylindrical, piezoceramic tubes has been determined in the low-frequency, omnidirectional range for various conditions of poling together with capped, shielded, and exposed ends. This range is more than a decade below the first resonance. NRL's computer program SHIP [Peter H. Rogers, NRL Report 7240 (June 1972)] is used in this report to examine the diffraction constants for finite length cylindrical radiators and circular pistons in the end of finite length tubes. The effect of diffraction upon the sensitivity of cylindrical elements with capped and shielded ends are calculated for radial, tangential and longitudinal poling.
Three-dimensional finite-element normal-mode calculations for flextensional underwater acoustic transducers
Authors: Boone Jack N.
Published: October 2005

A “curvilinear wedge” finite-element has been developed which is broadly applicable to the family of transducers variously classified as “flextionsional” [G. A. Brigham and L. H. Royster, J. Acoust. Soc. Am. 46, 92(A) (1969)]. The essential aspects of the direct development of the finite element in cylindrical coordinates are presented, with emphasis on advantages over elements employing polynomial mappings. The resolution of the problem of infinite energy density at the coordinate singularity is effected under conditions sufficiently general for the solution of problems arising in the mathematical modeling of flextensional transducers. Results for the short-circuited normal modes are presented for Class II, Class IV, and Class V configurations and compared to experimental and other analytical results for these transducers. Good agreement of the predicted spectra with reported experimental data is found. It is demonstrated that constraints in interface compatibility specifications in multicomponent models may produce large errors and involve generally untenable assumptions.
Distribution of timing events in speech production
Authors: Weismer G. , Ingrisano D. R.
Published: October 2005

The timing of articulatory gestures in speech production was studied in three speakers. Each speaker recorded a list of 400 sentences comprised of a randomized arrangement of 4 sentences by 5 emphatic stress conditions in which each sentence-emphatic stress combination was repeated 20 times, One sentence was designated as the target utterance, and the remaining three sentences were included as dummy utterances. Subjects were trained to place emphatic stress on a given content word in each utterance or to produce sentences with normal lexical stress patterns. Spectrograms of each target utterance-emphatic stress combination were prepared and analyzed according to a time normalization procedure in which the time of occurrence of predetermined events in the articulatory sequence was referred to the normalized utterance duration. The hypothesis tested in this investigation—as predicated by Martin's [Psych. Rev. 79, 487–509 (1972)] theory of timing in speech production—was that the repetition variance associated with the normalized “times-of-articulation” would be conditioned by the location of emphatic stress within utterances. Preliminary results tend to support this prediction. [Supported by NIMH Grant ♯R03-MH 28705-01.]
Syntactic determinants of word duration in speech
Authors: Goldhor Richard
Published: October 2005

A preliminary identification of the primary syntactic determinants of duration in English declarative sentences has been made. A hundred declarative sentences were generated from a small set of words, and the durational variations of those words which appeared in more than six sentences were studied. The three syntactic determinants which were found to most strongly and consistently affect word duration are: (1) the length of the phrase in which a word appears; (2) the position of the phrase in its dominating clause; and (3) the number and type of clauses in the sentence. Additionally, these determinants were found to affect phrase-final words differently than phrase-nonfinal words. These findings have been incorporated into a simple prosodic durational algorithm suitable for use in a text-to-speech system.
Performance of children from 11 to 17 years of age on a sentence test of speech intelligibility in noise
Authors: Elliott L. L.
Published: October 2005

Ninety-six normally hearing children (24 each at ages 11, 13, 15, and 17 years) were individually administered the Speech Perception in Noise (SPIN) Test (see preceding paper by Kalikow, Stevens, and Elliott) at signal-to-noise (SIN) levels of 5, 0, and −5 dB in counterbalanced order and in quiet. Their task was to repeat the last word of each sentence. Average performance of the 17-year old Ss was very similar to performance of adults on all conditions. An age effect appeared in the results for the high-predictability sentences at 0-dB S/N level, with younger Ss showing poorer performance. This age effect was specific to the listening-in-noise condition, since the 11-year-old Ss demonstrated perfect or near perfect scores when later tested in quiet. Implications of these findings will be discussed and the results of testing some children with learning disabilities will also be presented. [Supported by a grant from B.E.H.]