摘要:

A simple piece of equipment which makes it possible to simultaneously register the motion of the violin bow and the downward force on the string (‘‘bow pressure’’) under normal playing conditions is described. Registrations of various bowing gestures in violin playing obtained with the equipment are presented and discussed.

ISSN:0001-4966    

DOI:10.1121/1.393841

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

This paper examines the relationship between dynamic spectral features and the identification of Japanese syllables modified by initial and/or final truncation. The experiments confirm several main points. ‘‘Perceptual critical points,’’ where the percent correct identification of the truncated syllable as a function of the truncation position changes abruptly, are related to maximum spectral transition positions. A speech wave of approximately 10 ms in duration that includes the maximum spectral transition position bears the most important information for consonant and syllable perception. Consonant and vowel identification scores simultaneously change as a function of the truncation position in the short period, including the 10‐ms period for final truncation. This suggests that crucial information for both vowel and consonant identification is contained across the same initial part of each syllable. The spectral transition is more crucial than unvoiced and buzz bar periods for consonant (syllable) perception, although the latter features are of some perceptual importance. Also, vowel nuclei are not necessary for either vowel or syllable perception.

ISSN:0001-4966    

DOI:10.1121/1.393842

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Amplitude change at consonantal release has been proposed as an invariant acoustic property distinguishing between the classes of stops and glides [Mack and Blumstein, J. Acoust. Soc. Am.73, 1739–1750 (1983)]. Following procedures of Mack and Blumstein, we measured the amplitude change in the vicinity of the consonantal release for two speakers. The results for one speaker matched those of Mack and Blumstein, while those for the second speaker showed some differences. In a subsequent experiment, we tested the hypothesis that a difference in amplitude change serves as an invariant perceptual cue for distinguishing between continuants and noncontinuants, and more specifically, as a critical cue for identifying stops and glides [Shinn and Blumstein, J. Acoust. Soc. Am.75, 1243–1252 (1984)]. Interchanging the amplitude envelopes of natural /bV/ and /wV/ syllables containing the same vowel had little effect on perception: 97% of all syllables were identified as originally produced. Thus, although amplitude change in the vicinity of consonantal release may distinguish acoustically between stops and glides with some consistency, the change is not fully invariant, and certainly does not seem to be a critical perceptual cue in natural speech.

ISSN:0001-4966    

DOI:10.1121/1.393843

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Word identification in noise was measured adaptively underflatandrisingfrequency response conditions to represent basic alternatives for a hearing‐aid characteristic. The speech test results were compared with measures of sensitivity, loudness tolerance, frequency resolution, and temporal resolution in 23 hearing‐aid users with mild or moderate sensorineural hearing losses. Subjects also rated the two frequency responses for preference and subjective quality. A paradoxical relationship was found whereby superior speech performance under theflatcondition was associated with preference for therisingcondition, and vice versa. No combinations of psychoacoustic variables satisfactorily explained either relative performance or preference, although high‐frequency sensitivity and upward spread of masking were implicated. Absolute speech performance was related to sensitivity at 2 kHz, age, and sex, but not to frequency resolution once other factors were partialed. Temporal resolution was also a factor, but this was due largely to the influence of extreme values in two subjects. It is concluded that, for moderate degrees of hearing loss, speech identification in noise can be predicted from age, sex, and sensitivity with little advantage from recourse to measurement of frequency or temporal resolution.

ISSN:0001-4966    

DOI:10.1121/1.393844

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

The experiment presented here is a sequel to a previous investigation [N. G. Thorsen, J. Acoust. Soc. Am.77, 1205–1216 (1985)] and was designed to show whether a sequential fundamental frequency lowering of individual sentence components is present in a semantically, but not necessarily syntactically, coherent sequence (a text), when the number of sentences exceeds three. The results show that such a sequential lowering may appear, though it is not evenly distributed across the text. However, the textual intonation contour is sensitive not only to the number of sentences that make up the text, but also to the length of individual sentence components.

ISSN:0001-4966    

DOI:10.1121/1.393845

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

The optimum processor theory of Goldstein can, in principle, account for pitch perception phenomena involving simultaneous dichotic complex tones. The frequency‐coding noise function, which is the only free parameter of the model, was estimated with pitch identification data of two simultaneous two‐tone complexes presented to different ears. This ‘‘sigma’’ function was found to have a shape similar to that of the function derived from data on identification performance for single pitches. The sigmas in the simultaneous pitch identification experiment are larger by an amount that differs from subject to subject. By using different methods of data analysis it was found that the pitch estimation processes for the two tones are independent for most subjects. This allows a simple extension of Goldstein’s optimum processor theory.

ISSN:0001-4966    

DOI:10.1121/1.393846

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

The frequency contribution to the click‐evoked ABR wave V was examined in adults and 3‐month‐old infants through the use of notch‐filtered broadband noise. Notch center frequencies were set at 1.0, 4.0, and 8.0 kHz. Responses were obtained at 20, 40, and 60 dBnHL during the simultaneous presentation of each notched‐noise masker as well as in an unmasked condition. The ABR wave V was analyzed for absolute latency and amplitude, as well as latency and amplitude changes resulting from the introduction of masking. Analyses showed wave V latency and amplitude values to be similar for adults and infants within the 1.0‐kHz notch. Differences between adult and infant groups were observed as the notch was shifted to the high frequencies. Further, latency and amplitude shifts resulting from the introduction of masking noise produced differential effects on infant responses when compared to adults.

ISSN:0001-4966    

DOI:10.1121/1.393847

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

The fact that a titanium screw can be implanted into the mastoid portion of the human skull, at the same time establishing a permanent, reaction‐free skin penetration, has made it possible to attach a new bone conduction hearing aid directly to the skull. To understand and improve this new method of bone stimulation, the mechanical point impedance of the titanium screw–skull system was measured. The conventional point impedance of the skin‐covered mastoid portion of the temporal bone was also measured and the difference in magnitude between the two impedances was calculated. An impedance head (Brüel&Kj1r 8001) and an FFT analyzer (Hewlett–Packard 5423) were used for mechanical point impedance measurements. Seven patients have been investigated. The magnitude of the impedance for the screw–skull system was found to be generally between 10 and 30 dB higher than that for the conventional skin‐covered mastoid bone. One conclusion is that the conventional point impedance of the skin‐covered mastoid portion of the human skull is essentially due to the properties of the skin and subcutaneous soft tissue. Another conclusion is that a much lower stimulation velocity is needed, with skin penetration, to produce a given hearing sensation.

ISSN:0001-4966    

DOI:10.1121/1.393848

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

It was predicted that because the ear is spectrally tuned, it should be most affected by intense impulses with spectral peaks near the frequency where it is tuned best (3.0 kHz for the human ear) and progressively less affected by impulses at lower frequencies [G. R. Price, Scand. Audiol. Suppl.16, 111–121 (1982)]. This prediction is counter to all the DRCs for impulse noise; therefore an adequate test is essential. In order to augment the data on hearing loss to low‐spectral‐frequency impulses, three groups of cats (eight, nine, and ten animals) were exposed on one occasion to 50 impulses from a 105‐mm howitzer at peak SPLs of 153, 159, and 166 dB. Threshold shifts were measured electrophysiologically on the day of exposure (CTS) and following a 2‐month recovery period (PTS). Maximum PTSs appeared at 4 kHz (even though the spectral peak of the impulse had been at about 100 Hz), and CTSs recovered into PTSs about half as large. Furthermore, for group data, even small CTSs tended to have a permanent component. These data raise the question as to whether or notanythreshold shift persisting an hour or two after exposure to high levels should be considered tolerable. When compared with data from rifle fire exposures, the data confirmed the earlier prediction that as the spectral frequency drops, hazard declines at the rate of a little more than 3 dB/oct, contrary to the rating by existing DRCs.

ISSN:0001-4966    

DOI:10.1121/1.393849

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Finding close upper and lower bounds to eigenvalues in vibrations and elastic stability problems constitutes a highly desired situation for the applied mathematician or research engineer since their knowledge allows for a clear evaluation of the error involved when determining natural frequencies or buckling loads. Among the methods which allow for the determination of upper and lower bounds one must certainly cite the Kohn–Kato bounding technique. The present paper deals with a simple yet quite substantial optimization of the original approach by Kohn and Kato. It is shown that by inclusion of an exponential undetermined parameter in the coordinate function it is possible to minimize the upper bound and maximize the lower bound, improving considerably the ‘‘closeness’’ of the bounds, especially in the case of higher eigenvalues.

ISSN:0001-4966    

DOI:10.1121/1.393850

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP