bluuebunny/crossref_metadata_2025 huggingface dataset:
Speech recognition thresholds in temporally complex backgrounds: Effects of hearing loss and noise masking
Authors: Bacon Sid P. , Opie Jane M. , Montoya Danielle Y.
Published: October 2005

When listening to speech in a fluctuating background, subjects with normal hearing can operate at a higher signal-to-noise ratio (SNR) by taking advantage of momentary decreases in background level. Subjects with even a mild hearing loss are less able to do so. This was examined here in subjects with normal hearing, with sensorineural hearing loss, and with normal hearing whose pure-tone thresholds were elevated via masking to match those of the hearing-impaired subjects. Four backgrounds were used: speech-shaped nose (SS); speech-shaped noise modulated by the envelope of a single talker (ST); speech-shaped noise modulated by the envelope of a multi-talker babble (MT); and speech-shaped noise modulated by a 10-Hz square wave at a depth of 100% (SQ). The rms level of the background was 70 dB SPL. The level of the sentences was varied adaptively to obtain a recognition threshold SNR. For the normal-hearing subjects, the average SNRs in the ST and SQ backgrounds were 3 to 8 dB lower, respectively, than those for either the SS or MT backgrounds. There generally was less ‘‘masking release’’ for the hearing-impaired and noise-masked subjects. For some hearing-impaired subjects, the release was smaller than that in their noise-masked counterpart, suggesting the audibility alone may not always account for the reduced masking release observed in the hearing impaired. [Work supported by NIDCD.]
Frequency glide discrimination in the F2 region by normal-hearing and hearing-impaired listeners
Authors: Summers Van , Leek Majorie R.
Published: October 2005

Several researchers have suggested that the dynamic formant transitions present within consonant–vowel and vowel–consonant utterances may be poorly processed by hearing-impaired (HI) listeners. To investigate HI listeners’ processing of transitional stimuli, six HI and six normal-hearing (NH) listeners were asked to discriminate between frequency glides patterned after second formant transitions in English CV syllables. The influence of glide duration, rate, and frequency extent were examined for each group in quiet and in 35-dB spectrum level broadband noise. Glide rate did not show a significant direct effect on frequency difference limens (DLs) for glide onset. Reductions in glide duration and the presence of noise each led to significant increases in DLs. The magnitudes of these effects were similar across groups. The only significant group differences were observed for gradual glides of limited frequency extent. This finding is consistent with more accurate processing of ‘‘cochlear dispersion’’ cues on the part of NH listeners [Porter etal., J. Acoust. Soc. Am. 90, 1298–1308 (1991)]. [Work supported by NIDCD.]
A method for separation of detected underwater sound waves propagating in opposite directions
Authors: Guangye Chen
Published: October 2005

A new method to separate detected underwater sound waves propagating in opposite directions is presented in the paper. In the first part, the theoretical basis is provided with the derivation of related formula. The directivity pattern of reception is drawn. Then the experimental results are given in detail, which show good agreement with the theoretically predicted tendency. The factors causing the error are analyzed. Last, the further improvement of accuracy of experiment is suggested.
Some fundamentals of vibrotactile sensation
Authors: Verrillo Ronald T.
Published: October 2005

It is reasonable to propose that vibrotactile sensations can provide an effective channel to supplement auditory cues to aid the musical performer in the tonal control of the singing voice or an instrument. It is equally reasonable to assume that these sensations can provide cues to the nonsinging speaker, whether hearing or hearing impaired. In order to determine experimentally the efficacy of the vibrotactile channel as an aid to musical tonal control and speech, it is important that the fundamental characteristics of vibrotactile sensation be understood. These characteristics are presented for measurements at threshold and suprathreshold levels and for various subject variables, such as gender and age. [Work supported by grants from NIH, NIDCD.]
Phonatory head and chest vibrations in singers
Authors: Sundberg Johan
Published: October 2005

Western opera singers often report that they feel vibrations in the face and neck when they sing. As one perceives one’s own voice quite differently from one’s listeners, it has been hypothesized that such phonatory vibrations offer a more reliable feedback signal for the control of phonation than the airborne sound. Phonatory vibrations have been examined in previous research. The results suggest that in singing at fundamental frequencies lower than about 350 Hz (pitch F4) chest wall vibrations can be used as a feedback signal, as they seem to reflect glottal adduction, an aspect of great relevance to singers. Vibrations in the face and skull, on the other hand, seem to vary considerably between different vowels and thus seem to depend on formant frequencies rather than on voice source characteristics. Therefore such vibrations can be assumed to be more difficult to use as a feedback for controlling phonation.
Tactile feedback from brass instrument shell and air column vibrations
Authors: Hoekje Peter L. , Kjar David
Published: October 2005

The vibrations of the metal shell of a brass instrument can be discerned by the player through the player’s lips and hands. This is in addition to the vibrotactile feedback to the player’s lips from the acoustic vibrations in the air column of the instrument. Many players claim an improvement in playability when the mass of the mouthpiece is increased. Measurements of the body vibrations of a trumpet under playing conditions were obtained with an accelerometer at six locations: at three points on the mouthpiece, and also on the receiver, valve casing, and bell. The greatest amplitudes were observed at the bell. When mass was added to the mouthpiece, while keeping the sound level output of the instrument constant, the vibration amplitudes at the mouthpiece decreased as expected. However, the same degree of decrease was not observed at the other locations. This and other evidence suggests that increasing the mouthpiece mass does not significantly alter the coupling between the air vibrations and the shell vibrations. Thus, it is postulated that the playability benefits derive from a reduction in the conflict between the two channels of feedback to the lips.
The effects of hyperbaric conditions on vibrotactile thresholds
Authors: Bolanowski Stanley J. , Verrillo Ronald T. , Baran Frances , Smith Paul F.
Published: October 2005

The effects of low-frequency, water-borne vibration upon swimmers and divers are virtually unknown. It has been reported that divers can ‘‘feel’’ underwater sounds on various parts of their bodies. The current experiments were conducted as an initial investigation of these reports to determine if barometric pressure and breathing mixture has an effect on vibrotactile thresholds measured in air. Vibrotactile thresholds at the thenar eminence were determined on four divers during a ‘‘saturation dive’’ (8 days) in a dry hyperbaric chamber. Measurements were made prior to the dive (pre-test) in a normobaric environment (sea level) at 132 ft of seawater (fsw), at 198 fsw, at 300 fsw, and following the dive at sea level (post-test). The gas mixture in which the divers lived was varied according to standard procedures to prevent adverse body reactions during compression and decompression. Vibrotactile thresholds were measured by standard procedures at 1, 10, 100, and 250 Hz. Results indicate that neither air pressure nor breathing mixture had any effect on vibrotactile thresholds within any of the four mechanoreceptor channels that innervate normal skin. The results are internally consistent within this experiment and also when compared to threshold standards accumulated over thirty years. [Work supported by Geo-Centers, Inc. under Navy Contract.]
Tactual performance with motional stimulation of the index finger
Authors: Tan Hong Z. , Durlach Nathaniel I. , Rabinowitz William M. , Reed Charlotte M.
Published: October 2005

The results of two studies investigating performance with motional stimulation applied to the finer will be reported. Experiments were conducted using a position-controlled servomotor that delivers large-amplitude displacements in the frequency range of 1–32 Hz to the fingerpad of the index finger. In one study, measurements of amplitude and frequency discrimination were obtained as a function of reference frequency, reference displacement, and duration. Results obtained for low-frequency motional stimulation will be discussed and related to results reported in the literature for vibrational frequencies. In a second study, computer-generated sequences of International Morse code were delivered to the fingertip using high-amplitude square-wave stimulation. The ability to identify Morse code sequences was studied as a function of rate of presentation and length of the stimulus stream for subjects who were either naive or highly experienced in the traditional sending and receiving of Morse code. Results will be discussed in terms of the differences in learning and information transmission rates between naive and experienced subjects. [Work supported by NIDCD.]
Examining the effects of long-term experience using tactile supplements to speechreading
Authors: Auer Edward T. , Bernstein Lynne E. , Coulter David C.
Published: October 2005

Typically, studies evaluating tactile supplements to speechreading are relatively short in duration and limited to the laboratory. Results from an ongoing 10-month study of the effectiveness of four tactile devices will be presented. Two devices encode voice fundamental frequency (F0): One encodes F0 as rate of vibration of a single solenoid, and the other as both rate and location of vibration on a linear array of eight solenoids. Two devices are 16-channel vibrotactile vocoders: One encodes wideband speech spectral information, and the other encodes the F2 range of frequencies. Subjects are adults with pre- and post-lingual profound hearing impairments and are each assigned to use a single device for the duration of the study. Some of the subjects assigned to the single channel F0 device are also using a wearable version outside the laboratory. Comparisons of the effectiveness of all four devices over long-term exposure are being conducted using both traditional performance measures and novel measures of on-line cognitive processing. To data, 10–20 percentage point improvements in identification of words in sentences have been observed with the single channel device.
Effects of haptic movement on tactile pattern identification
Authors: Weisenberger Janet M. , Hasser Christopher J.
Published: October 2005

Craig [Percept. Psychophys. 30, 151–166 (1981)] found that tactile perception of complex vibratory patterns presented to the fingertip was better for ‘‘static’’ patterns that did not move across the display than for ‘‘scan’’ patterns that moved horizontally across the display. It is possible that Craig’s finding resulted from the fact that observers did not have active control of the movement of the scan patterns. In the present work, tactile patterns were presented to the fingertip under three modes: a static mode in which stimuli did not move; a passive scan mode in which stimuli moved horizontally across the display under a stationary fingertip; and a haptic scan mode in which observers moved the fingertip and the display across a virtual surface containing the stimulus. Results with a set of simple patterns showed no differences across modes, with all modes yielding performance greater than 90% correct. To eliminate the possibility of ceiling effects, a second experiment was conducted with a more complex stimulus set. Preliminary results showed lower levels of performance for all presentation modes, with the haptic scan mode showing the best performance. Results are discussed in terms of development of tactile displays for sensory communication and telerobotics applications.
Passive-active isolator control of sound radiation from a raft-cylinder system
Authors: Fuller C. R. , Toffin E.
Published: October 2005

This paper analytically investigates the active-passive control of sound radiation from an elastic finite cylinder containing a rigid raft mounted on active-passive isolators. The disturbance is narrow band and acts at various locations on the internal raft. The control cost function is constructed from radiated far-field pressure or supersonic shell structural wave-number estimates in contrast to the usual practice of minimizing vibration directly under the mount attachment point. A control effort term is included in the cost function to overcome the problem of an undetermined system when many isolators are used. The results demonstrate that, using an acoustic-based cost function in conjunction with a fully coupled control approach of the active-passive isolators leads to significant radiated sound reduction with a very low control effort. The mechanism is similar to ‘‘modal restructuring’’ observed in previous plate studies. The results are contrasted to direct minimization of vibration at the attachment points. The influence of passive variables such as mount damping and stiffness on the control forces and the associated sound reduction are also studied. [Work supported by ONR.]
Active control of interior noise in a business aircraft using piezoceramic control actuators
Authors: Gibbs G. P. , Fuller C. R.
Published: October 2005

This paper describes results of experiments in which active control of interior noise in a business aircraft is achieved using piezoceramic actuators bonded to the fuselage structure. The experiments were performed in a real aircraft fuselage (Cessna Citation 3) with engine noise simulated by a point force shaker attached to the engine pylon, and multiple arrays of piezoelectric control actuators in conjunction with an LMS adaptive controller. The cost function used was the summation of the pressure squared at four error microphones located at head height in proximity of the two rear-mounted passenger seats. Results are given for on-resonance and off-resonance cases and sound level reductions from 3 to 15 dB were demonstrated. The global nature of the control and influence of the actuator/sensor positioning is discussed.
Active control of noise radiated into an enclosure
Authors: Wang Lily M. , Varadan Vasundara V. , Varadan Vijay K.
Published: October 2005

Control of noise radiated into an enclosure from an external source is of interest in several applications. The noise is transmitted into the enclosure by the induced structural vibrations of the walls of the enclosure. An active control experiment using discrete piezoelectric sensors and actuators is proposed to sense and control the structure-borne sound. A sound level meter and error microphone are used to measure the acoustic field intensity inside the enclosure with and without control. The results of this experiment will define the feasibility of applying active control methods to larger enclosures such as office partitions, passenger compartments of vehicles, control rooms in factory floors, hospital rooms, and apartments in crowded urban areas.
Memory for vowel exemplars
Authors: Johnson Keith
Published: October 2005

Listeners can recognize both the voice of a familiar speaker and the words spoken. The experiment reported in this paper explored the interaction of these two perceptual abilities. In particular, it was hypothesized that vowel perception is tied to speaker identity. This hypothesis predicts that vowel perception performance will vary as a function of the listener’s exposure to the voice of the speaker. Two speakers served as models for sets of synthetic vowels which matched the speakers’ voice characteristics, formant bandwidths, and higher formant values. Eight groups of listeners manipulated the frequencies of the two lowest formants in a method of adjustment paradigm. The task was to make the synthetic vowel match the vowel qualities of words illustrating the monophthongs of English. For each voice, one group of listeners had no prior exposure to the target speaker, and three groups listened to one of three tape recordings of the speaker (and were instructed to ‘‘memorize the speaker’s voice and make the synthetic vowels match the speakers pronunciation’’). The results showed that exposure to a speaker’s voice had an influence on the formant values chosen by the listener, that listeners were able to retain acoustic/auditory information about vowel exemplars.
Effects of intonation context on the perceptual integrality of F0 and F1 in vowels
Authors: Benki Jose R. , Bartels Christine , Kingston John , Macmillan Neil A.
Published: October 2005

Two of the dimensions along which vowels vary, rate of vocal fold vibration (F0) and tongue height (F1), covary directly in natural speech. These experiments examined whether F0 and F1 integrate perceptually for vowels in contrastive intonation contexts, as they have been shown to do in isolation [Kingston, Phonetica 47, 149–179 (1991)]. The vowels occurred in the second, stressed syllable of a [wschwa′w—wschwa] frame bearing either a [H+L* H−L%] or [L+H* L−L%] intonation contour. This set of contexts was designed to affect listeners’ expectations about the value of F0 in the target vowel. Listeners classified the imperfectly discriminable vowels by F0 and/or F1, according to the different tasks of the Garner paradigm. Both accuracy and response time were measured. The perceptual representation of the vowels can be inferred from a detection-theory analysis of the accuracy data; response times facilitate comparison of the results with the bulk of other work using the Garner paradigm. [Work supported by NIH and NSF.]
Perception of back vowel height: Effects of varying F1-F0 bark distance
Authors: Fahey Richard P.
Published: October 2005

Using front vowels, Hoemeke and Diehl [J. Acoust. Soc. Am. 93, 2422(A) (1993)] confirmed that F1-F0 (in bark) is a perceptual correlate of vowel height [Traunmüller, J. Acoust. Soc. Am. 69, 1465–1475 (1981)], and that the [+high]/[−high] boundary falls at 3–3.5 Bark F1-F0 [Syrdal and Gopal, J. Acoust. Soc. Am. 79, 1086–1100 (1986)]. The present study replicates Hoemeke and Diehl’s experiments, using back vowels. Listeners identified three sets of synthetic vowels varying orthogonally in F1 and F0, ranging between /u/–/u/, /u/–/open oh/, and /open oh/–/open aye/. In a variable higher-formant condition, F1-F0 better predicted labeling than did F1 for both the /u/–/u/ and /u/–/open oh/ series. Scatterplots of F1-F0 vs labeling scores were most steplike for the /u/–/open oh/ ([+high]/[−high]) series, with the boundary at 3–3.5 Bark. In a fixed higher-formant condition, F1-F0 better predicted labeling than did F1 for the /u/–/u/ series. Although less clearly so, the most steplike scatterplot was again that for the /u/–/open oh/ series, with a boundary at 3–3.5 Bark F1-F0. [Work supported by NIDCD.]
Influence of multipole test sessions on perceptual weight of voicing cues
Authors: Sawallis Thomas R.
Published: October 2005

Previous research [T. R. Sawallis, ICSLP 92 Proc. 2, 1067–1073 (1992)] has shown the feasibility of using techniques from signal detection theory to quantify perceptual weights of acoustic cues. Their abstract nature makes these weights autonomous and generalizable across cues and conditions, unlike trading relations which use proportions to bind physical scales. These weights are also environmentally valid because the experimental design avoids multiply-edited ‘‘prototypes’’ in favor of multiple singly edited natural tokens. This preserves the behavior of the nontarget cues against which the experimental cues are balanced. Using the French intervocalic /t-d/ contrast, this measure has been shown to be influenced by the listener’s linguistic background (both native language and linguistic training) [T. R. Sawallis, J. Acoust. Soc. Am. 93, 2390(A) (1993)]. However, these results reflected only the subjects’ first sitting of the perceptual test. This paper reports the influence of multiple sittings of the test on both accuracy (i.e., error rates for edited and unedited tokens) and perceptual weight (i.e., sensitivity to the edited cue).
Influence of silence duration distribution in perception of stop consonant clusters
Authors: Govindarajan Krishna K. , Cohen Michael A.
Published: October 2005

The effects of the silence duration between two different stop consonants in /VC1–C2V/ tokens were examined. Earlier results using synthetic stimuli had shown that the decision boundary between hearing one and two stop consonants varied as a function of the range and frequency number of tokens) of the silent interval [B. H. Repp, Haskins Lab. Stat. Rep. Speech Res. SR-61, 151–165 (1980)]. Using real speech stimuli, The Repp (1980) experiment was replicated, showing that the results hold for individual subjects. Extending this result, the overall variance of the silence duration distribution was manipulated while maintaining the same mean, for two different distributions. The result shows that the overall variance does not significantly affect the boundary, and that listeners must be adapting to the mean silence duration. The final experiment examines this adaptation by presenting trials of sequential tokens to determine the relative weighting of the former token(s) on the judgment of the final token in the trial. The results of this experiment will be presented in relation to the adaptation process. Implications for adaptation in other durational cues, and influence of cue trading will be discussed. [Work supported by AFOSR.]
Syllable- and rhyme-internal timing: Combined effects of postvocalic voicing and distinctive vowel length in Norwegian
Authors: Behne Dawn M. , Moxness Bente
Published: October 2005

Syllable-internal timing can be affected by a variety of factors, including distinctive vowel length and postvocalic voicing. Distinctive vowel length, which occurs in Norwegian, and postvocalic voicing have typically been found to inversely affect vowel duration and the closure duration of a postvocalic consonant. When these factors converge on a syllable, syllable-internal timing simultaneously reflects the concurrent influence of distinctive vowel length and postvocalic voicing. Research on English [D. M. Behne and L. C. Nygaard, J. Acoust. Soc. Am. 93, 2296(A) (1993)] has shown that when multiple factors concurrently influence syllable-internal timing, their effects occur independent of each other. The goal of the present study is to examine the effects of distinctive vowel length and postvocalic voicing on syllable- and rhyme-internal timing, and characterize the concurrent effect of these factors. A set of 12 Norwegian CVCs containing /i, o, a, i:, o:, a:/ before a final voiced and a final voiceless consonant were produced in context by 12 native speakers of Norwegian. Results indicate that syllable-internal timing is independently affected by distinctive vowel length and postvocalic voicing, however their effects on syllable-internal timing were found to differ. These findings will be discussed in terms of syllable- and rhyme-internal timing.
An analysis of mismatch induced range localization error in conventional matched-field processing
Authors: Smith George B. , Akundi Murty A.
Published: October 2005

In this work the environmental mismatch problem in matched-field processing is addressed by attempting to obtain analytic expressions for mismatch-induced range localization error and signal gain degradation for a linear (replica correlator) matched-field processor using simple models such as the rigid and Pekeris waveguides. This analysis is based on the concept that these types of errors are the result of mismatch-induced dephasing of the modally interfering components of the acoustic field in the waveguide. As these modal components dephase, the signal peak degrades, and it forms at a location slightly different from the correct location. In particular, which types of mismatch produce a substantial range localization error have been determined and the frequency dependence of such range shifts has been studied. The analytic results have been substantiated with computer simulations. [This work was supported by the Office of Naval Research, Program Element 61153N, with technical management provided by the Naval Research Laboratory, Stennis Space Center, MS.]
Matched-field processing in a shallow-water channel with a random bottom
Authors: Krolik Jeffrey L. , LePage Kevin D.
Published: October 2005

An important source of uncertainty in shallow-water propagation models used for minimum variance (MV) matched-field processing is bottom roughness or irregular bathymetry. A perturbative solution to the Helmholtz equation which gives the point source field in a shallow-water waveguide with rough boundaries has been derived in [W. Kuperman and H. Schmidt, J. Acoust. Soc. Am. 86, 1511–1522 (1989)]. This formulation yields an expression for the point-source wave front correlation matrix which is determined by the coherent field and a scattered field generated by random secondary sources at the bottom interface. Alternatively, adiabatic normal modes and first-order perturbation of the horizontal modal wave numbers also provides a solution for the wave front correlation matrix in terms of the second-order statistics of the random bottom depth. In this paper, matched-field source localization performance under both these models is evaluated for several MV beamforming approaches. Minimum variance beamforming with environmental perturbation constraints [J. L. Krolik, J. Acoust. Soc. Am. 92, 1408–1418 (1992)] is demonstrated to be an approach which can exploit these random propagation models to achieve robust matched-field source localization. [Work supported by ONR.]
Environmental data assimilation in matched-field processing with a random normal mode model
Authors: Krolik Jeffrey L.
Published: October 2005

Numerical acoustic propagation models used in matched-field processing typically assume that ocean environmental parameters, such as the range-dependent sound-speed profile, are either known exactly or are characterized by stationary prior statistics. However, neither of these modeling approaches is well suited for accurately assimilating measurements of the correct ocean realization into the calculation of point-source acoustic wave front statistics. In this paper, environmental data is assimilated into a random adiabatic normal mode propagation model by calculating the conditional correlation matrix of an acoustic wave front given a set of contemporaneous sound-speed profile measurements made at different points in space. First-order perturbation theory is used to map the conditional statistics of Gaussian-distributed excess sound-speed variations into an estimate of the conditional point-source wave front correlation matrix. Minimum variance beamforming with environmental perturbation constraints [J. L. Krolik, J. Acoust. Soc. Am. 92, 1408–1419 (1992)] conditioned on current environmental measurements is demonstrated as a means of exploiting this random wave front model to achieve improved matched-field source localization performance. [Work supported by ONR.]
Source tracking in the Hudson Canyon experiment
Authors: Porter Michael B.
Published: October 2005

In this shallow-water experiment a source was towed at midchannel depth to a range of 6 km from a vertical line array. The source simultaneously hummed four tones with pitches from 50 to 600 Hz. Using the matched-field approach, an acoustic model was used to scan a beam through range and depth in the channel. It is shown that the source can be tracked continuously by combining the data from all four frequencies.
Repetition priming in auditory word recognition
Authors: Hamburger MaryBeth , Slowiaczek Louisa M.
Published: October 2005

Repetition priming, faster response times to a word when it is preceded by an identical rather than an unrelated prime, has been repeatedly obtained using diverse methodologies and stimuli. However Slowiaczek and Hamburger [J. Exp. Psychol. Learn. Mem. Cognit. 18, 1239–1250 (1992)] failed to find repetition priming for auditorily primed, monosyllabic, auditory words. They suggested that strategic processing caused by list context effects was responsible. Repetition priming, however, was not obtained when strategic processing was reduced [M. B. Hamburger and L. M. Slowiaczek, J. Exp. Psychol. Learn. Mem. Cognit. (under review)]. The current experiments further investigate repetition priming in auditory word recognition. Subjects shadowed auditorily presented targets preceded by unrelated, phonologically similar, or identical auditory primes. Phonological similarity [whether prime-target pairs shared one phoneme (low similarity) or three phonemes (high similarity)] and likelihood of strategic processing were manipulated. Results demonstrated that repetition priming can be found for auditorily primed, monosyllabic, auditory words when subjects are not exposed to high similarity, phonologically related prime-target pairs. This effect is greater when strategic processing is reduced. [Work supported by NIH grant NS-29286-03.]
Changing the duration of silent-center syllables affects ‘‘perceptual lengthening.’’
Authors: Clarke William D.
Published: October 2005

In a previous study [Clark, J. Acoust. Soc. Am. 93, 2423–2424(A) (1993)], listeners identified ten American English vowels in dVd silent-center (SC) syllables. Syllables were presented in both natural and synthetic form embedded in a naturally spoken sentence. The synthetic syllables were modeled on the natural syllables so that formant trajectories were identical. While performance on both natural and synthetic unmodified syllables was very good (98% correct), errors in the synthetic SC condition exceeded errors on natural SC syllables (23% vs 11%). Most errors were on short lax vowels (44% errors on lax vowels versus 4% on tense vowels) which were misinterpreted as spectrally similar long vowels. The present study tested the hypothesis that ‘‘perceptual lengthening’’ may have occurred for SC syllables. Silence duration was reduced 33% and 67% in both natural and synthetic SC syllables. For natural SC syllables the error rate did not change. For synthetic SC syllables errors on lax vowels were reduced to 41% and 20%, respectively. The results suggest that listeners were using syllable duration cues to identify vowels in synthetic SCs more than in natural SCs. Thus perceptual lengthening had a greater effect on perception of synthetic syllables. [Work supported by NIDCD.]
Lexical access is influenced by vocal expression of emotion
Authors: Wurm Lee H. , Vakoch Douglas A.
Published: October 2005

Most studies of lexical access have ignored the possible effects of vocal expression. Words, however, always occur within a context, which can be either congruent or incongruent with the word’s denotative meaning. Given the importance of vocal characteristics in differentiating between emotions, emotion words are likely candidates for identifying such congruence and incongruence effects. Subjects performed an auditory lexical decision task in which stimuli consisted of pure emotion adjectives presented in an emotional tone of voice. Stimuli were chosen to provide maximally distinct clusters of emotion adjectives as defined by a two-dimensional lexical space [R. L. Morgan and D. Heise, Soc. Psychol. Q. 51, 19–31 (1988)]. The meaning of the adjectives was either consonant or dissonant with the tone of voice in which the word was spoken. The results of this study clarify the conditions under which lexical access is inhibited and facilitated by the vocal expression of emotion.
Perceived similarity of vocal expression of emotion
Authors: Vakoch Douglas A.
Published: October 2005

The present study extends traditional approaches to determining the discriminating features of vocal expressions of emotions by visually representing some of the auditory characteristics of speech. This allows the use of a more extensive array of vocal stimuli that if the stimuli were rated in listening tasks. Such an approach is particularly appropriate because a number of the important determinants of different emotions are conveyed in the fundamental frequency and its patterning. Thus an examination of the intonation contours provides substantial information to differentiate emotions. Subjects sorted visual representations of the pitch contours of a range of emotions into groups that looked similar. The dissimilarity of any two representations was determined by counting how often subjects placed the representations in the same group. These measures of dissimilarity were used as input for multivariate analyses. Different emotions were located along continua using multidimensional scaling, and cluster analyses identified discrete groupings of emotions.
Attentional allocation during speech perception: Evidence from phoneme monitoring
Authors: Wurm Lee H. , Samuel Arthur G.
Published: October 2005

Previous work [Frauenfelder etal., JEP:HPP 16, 77–91 (1990)] tested a critical prediction of the TRACE model of speech perception [J. L. McClelland and J. L. Elman, Cog. Psychol. 18, 1–86 (1986)]. Frauenfelder etal. found no evidence of inhibitory lexical effects on performance of a phoneme monitoring task, and concluded that the TRACE model was inaccurate. However, recent experiments [L. H. Wurm and A. G. Samuel, J. Acoust. Soc. Am. 94, 1883(A) (1993)] showed that the earlier conceptualization of the problem had several limitations, and that the question of inhibitory lexical effects was still unanswered. This experiment extends that work, examining specifically the role of attentional allocation during the phoneme monitoring task. In dual-task paradigm [e.g., M. I. Posner and S. J. Boies, Psychol. Rev. 78, 391–408 (1971)], stimuli were presented dichotically to subjects, who simultaneously monitored for specified phoneme targets in speech and for frequency modulations in a pure tone. Reaction times to frequency modulations were measured as a function of their locations relative to phoneme changes in nonword stimuli. The results of this line of research clarify the role played by attentional processes during speech perception, and whether indirect lexical inhibition should be included in models of lexical access. [Work supported by AFOSR.]
The effect of discriminability on dimensional interactions of pitch with vowel and consonant identity
Authors: Surprenant Aimee M. , Kewley-Port Diane
Published: October 2005

The ability to ignore irrelevant variation in the speech signal is essential for normalizing across speakers and situations. Past research has indicated that irrelevant variation in such features as pitch and vowel quality caused more interference on a consonant classification task than the reverse. Along with other more memory-oriented paradigms such as serial-list recall, this has been taken as evidence that the longer-lasting, periodic elements of sound that make up vowel and pitch information remain longer in auditory memory, thereby interfering with judgments about consonant identity. However, in most of these demonstrations, the relative discriminability of the tokens was not controlled. In the present study, discriminability was assessed for continua of pitch, consonant and vowel identity for stop-vowel syllables. Eight well-trained subjects were asked to make speeded same–different judgments on one dimension of stimuli that varied on two dimensions. An interaction for both response time and accuracy was found such that as the discriminability of the relevant dimension was increased, interference from the irrelevant dimension decreased and vice versa. Although there were minor variations, the same general pattern was observed in all conditions. [Research supported by NIDCD.]
Researchers beware: Use of speech-modulated noise adds strong ‘‘bottom-up’’ cues to phonemic restoration
Authors: Bashford James A. , Warren Richard M. , Brown Chris A.
Published: October 2005

When deleted segments of speech are replaced by extraneous sound, the missing speech fragments may be perceptually restored and intelligibility improved. This phonemic restoration (PhR) effect has been used to measure various aspects of speech processing, with deleted portions of speech typically replaced by Gaussian noise. However, several recent studies [e.g., A. G. Samuel, J. Mem. Lang. 26, 36–56 (1987)] used noise that followed the amplitude envelope of the speech fragment, providing precise moment-by-moment control over the signal/noise ratio, but also possibly providing envelope cues concerning the replaced speech. The present study examined this possibility by comparing the effects of Gaussian noise and speech-modulated noise interrupters upon the restoration of intelligibility. Filling periodic interruptions in sentences with modulated noise produced twice the intelligibility increase obtained with Gaussian noise. Further, when isolated monosyllables were interrupted, interpolation of modulated noise increased intelligibility whereas Gaussian noise reduced intelligibility. It is suggested that, although the enhancement of intelligibility of speech-modulated noise is an interesting topic, the results obtained with the stimulus are confounded by the addition of bottom-up information not present when PhRs are produced by independent extraneous sounds. [Work supported by NIH.]
Spectral restoration of speech by noise
Authors: Riener Keri R. , Warren Richard M. , Bashford James A.
Published: October 2005

Two types of perceptual synthesis (or auditory induction) have been reported that can minimize or cancel the effects of masking upon speech: Phonemic restoration can enhance intelligibility of speech when segments are replaced or masked by noise, and contralateral induction can prevent mislateralization of speech masked at one ear [see R. M. Warren, Psychol. Bull. 96, 371–383 (1984)]. A third type of auditory induction, ‘‘spectral restoration,’’ is reported, which can enhance intelligibility when deleted regions of the speech spectrum are replaced by noise. Separate groups of listeners heard lists of sentences consisting of two widely separated bands having low intelligibility. When an appropriate noise was added to the spectral gap separating the bands, a significant improvement in intelligibility was observed. It is suggested that spectral restoration represents a mechanism capable of enhancing comprehension of speech when portions of its spectrum are masked.
The representation of the place of nasal stops in word recognition
Authors: Myers James T. , Luce Paul A.
Published: October 2005

Predictable aspects of the representations used in the perception of a word may not be necessary for recognition of the word to be successful. The present study investigates whether relative predictability of place in nasal stops affects recognition of words. Subjects were given an auditory lexical decision task in which each target time was preceded by an auditory prime. Target words ended in /mp/ (BUMP), /nt/ (BUNT), /m/ (BUM), or /n/ (BUN). Primes ended in /m/ (UM), /nl/ (UN), or /k/ (UK). Place of the nasal stops is predictable in /mp/ and /nt/ words given the place of the following obstruent. Some current theories of phonological underspecification also claim that place in /n/ words is predictable, assuming that coronal is universally the default place. It was found that /mp/, /nt/, and /n/ words were primed equally well by /m/ and /n/ primes, implying that the specifics of place were not relevant in these words. By contrast, /m/ words were primed significantly better by /m/ primes relative to /n/ primes, implying that the representation of place in /m/ words is relevant for recognition. [Work supported by NIDCD.]
Bimodal perception of spectrum compressed speech
Authors: Paarmann Larry D. , Wynne Michael K. , Pugh Carmen M. , Bi Jun
Published: October 2005

In this study, ten normal-hearing adult listeners were asked to identify CUNY nonsense syllables presented auditorily and bimodally (audition and vision) via video tape in two conditions: Low-pass filtered and spectrum compressed by means of nonlinear sampling in the frequency domain [L. D. Paarmann, M. D. Guiher, and M. K. Wynne, J. Comp. Users Speech and Hear. 7, 257–281 (1991)]. The data collected were analyzed using a 2×2 ANOVA to determine if significant differences exist across the two main effects and if the interaction between the variables is significant. Although this study does not directly address the effectiveness of spectrum compression of the speech signal to improve speech understanding for hearing-impaired listeners, the results do strongly support the hypothesis that spectrum compressed speech is more intelligible to normal-hearing listeners than low-pass filtered speech with the same bandwidth, and it suggests that, especially in a bimodal listening situation, hearing impaired listeners’ speech intelligibility could be improved by such a processing method.
The internal structure of phonetic categories is robust
Authors: Hodgson Philip , Miller Joanne L.
Published: October 2005

Earlier data were presented that underscored the fine-grained internal structure of phonetic categories and the dependence of this structure on the multiple acoustic properties underlying a given phonetic segment [J. Acoust. Soc. Am. 92, 2464(A) (1992)]. Specifically, it was shown that two properties specifying the distinction between stay and sayF1 onset frequency and silence duration preceding F1 onset, enter into a within-category trading relation, as revealed by category goodness judgments of stay: These properties jointly determine which variants are perceived as the best exemplars of stay. The current study examined the robustness of these effects. It was found that both the fine-grained category structure and the within-category trading relation were maintained even when the stimuli were presented in multitalker ‘‘babble’’ noise at an adverse S/N ratio (0 dB). Moreover, we found that these effects held for sinewave replicas of the speech stimuli, for fully half of the subjects tested (the other half yielding a variety of response patterns, as is typical of sinewave speech). These findings attest to the robustness of within-category structure, including its dependence on multiple acoustic properties. Such robustness would be expected if within-category structure plays a central role in the perception of speech. [Work supported by NIH.]
Exploration of the phonetic structure of cues for places of articulation
Authors: Pastore Richard E. , Farrington Shannon M. , Acker Barbara E.
Published: October 2005

A multitask, multidimensional approach was used to evaluate the nature of perceptual space and relative importance of auditory cues for the perception of initial position voiced stop consonants of English. For /i/, /a/, and /u/ vowel contexts, stimuli varying systematically in F2- and F3- onset time and the nature of the initial release burst were examined from several different perspectives. For each vowel, a within-subject design was used, evaluating the stimuli in terms of speeded classification, goodness, and similarity, with the similarity scaling results submitted to a multidimensional analysis. Each of the tasks and stimulus parameters have been the focus of prior research, but have never been combined to provide a comprehensive, systematic description of perceptual space to provide converging evidence for the structure of phoneme categories and the interrelationships of cues for these categories.
Transients at stop-consonant releases
Authors: Massey Noel S.
Published: October 2005

The acoustic properties and perceptual significance of transients at the release of stop consonants and affricates was studied. The theory of transient production is based on a model in which pressure is built up in a closed tube and the radiated sound is calculated following an abrupt release of the pressure. Acoustic analysis of the amplitude and frequency content of transients in utterances from ten speakers was used as a guide in setting the parameters of the model. A speech synthesizer was modified to allow the generation of transients with frequency content similar to that observed in natural speech. Utterances consisting of a stop consonant or affricate followed by the vowel /a/, with various amplitudes of an initial transient, were synthesized, and listeners were asked to judge the naturalness of the stimuli. Listeners tended to prefer the presence of a transient with an amplitude approximating the measured amplitude in natural speech, although there was some variability in the responses. [Work supported in part by a grant from NIDCD.]
Frequency contrast and the effect of preceding liquid on perception of place of articulation
Authors: Lotto Andrew J. , Kluender Keith R.
Published: October 2005

Perception of syllable-initial /d/ and /g/ can be affected by the composition of preceding acoustic information such that, for a series of synthesized consonant-vowel syllables (CVs) varying in onset characteristics of the third formant (F3) and varying perceptually from /da/ to /ga/, subjects are more likely to perceive /da/ when preceded by the syllable /al/, and to perceive /ga/ when preceded by /ar/ [V. A. Mann, Percept. Psychophys. 28, 407–412 (1980)]. In the present studies, this initial finding was replicated, and a second experiment was conducted to evaluate the extent to which the effect could be attributed to general properties of auditory perception. Members of a 10-step series of /da-ga/ syllables varying in F3 onset frequency were preceded by the syllables /ar/ and /al/ and by frequency modulated (FM) glide analogues of F3 from those syllables. Analogues were 150-ms sine wave glides that followed the trajectory of F3 in /al/ or in /ar/, and were amplitude matched to the rms energy within a critical and in the vicinity of F3 for the /al/ or /ar/ syllables. The effects of single FM glides were analogous to those found for /al/ and /ar/, thus suggesting that general contrast effects may be implicated. [Work supported by NIDCD grant DC-00719 and NSF grant DBS-9258482.]
Perceptual significance of locus equations
Authors: Fruchter David E.
Published: October 2005

Identification curves were estimated for the English consonants /b, d, g/ using five-formant CV synthetic stimuli comprehensively sampling the F2 onset×F2 vowel acoustic space in the vicinity of Sussman’s /b, d, g/ locus equations [H. Sussman etal., J. Acoust. Soc. Am. 90, 1309–1325 (1991)]. The stimuli included ten English monophthongal vowel contexts, eleven levels of F2 onset per vowel, and three levels of F3 onset orthogonally varied with the F2 variable (ten vowels×eleven F2 onsets×three F3 onsets=330 stimuli). After brief training, each subject was presented several repetitions of each of the above 330 stimuli, two repetitions per day, over a period of several days. Subjects were instructed to choose one of five identifications: Initial consonant /b/, /d/, /g/, or /w/ or ‘‘no consonant.’’ Systems of identification curves were visualized as surfaces floating over Sussman’s locus equation space in order to judge the degree of correspondence between his acoustic results and these perception results. The current perception results are also compared to those of a similar experiment utilizing two-formant syntheses [A. Liberman etal., Psychol. Monogr. 68, 1–13 (1954)].