摘要:

Reliable data on tone systems has been assembled through a survey of a large sample of tone languages. Simple two‐tone systems are the most frequent; added tones reduce the frequency of occurrence. While two‐ and three‐tone systems generally have only level tones, both level and contour tones are commonly included in four‐tone systems. Five‐tone systems generally include level, rising and falling tones, while contours that move in the same direction but differ in the amount of pitch change are typically found only in large tone inventories. Thus, the commonest inventories exploit only contrasts of pitch level, larger inventories add contrasts on a dimension of direction of movement, and only the most elaborate and least common inventories are likely to use contrasts of amount of change. These dimensions correspond in ranking with the cognate perceptual dimensions ofaverage pitch, direction, andslopefound by Gandour and Harshman [Lang. Speech21, 1–33 (1978)]. Here the ranking implies, roughly, that subjects relied most on the average pitch dimension to discriminate between tones, then next they relied on the direction dimension, and so on. The correspondence between the two rankings suggests that tone inventories are elaborated by recruiting progressively less salient perceptual dimensions.

ISSN:0001-4966    

DOI:10.1121/1.2017207

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

It is well known that the duration of a stop consonant in the intervocalic, poststressed position may serve as a cue to that stop's voicing characteristic [L. Lisker, Lang.33, 42–49 (1957)]. More recent research has suggested that when stop‐closure durations are examined in a variety of positions, the voiceless stops have greater duration than the voiced stops only in the intervocalic, poststressed position [L. Lisker in A. Valdman [Ed.],Papers in Linguistics and Phonetics to the Memory of Pierre Delattre, 339–343 (1972)]. The present research was designed to provide additional data on stop‐closure durations as a function of (1) voicing, (2) stress, (3) vowel context, and (4) place of articulation. Six subjects produced a series of nonsense disyllables of the form CVCVC in a carrier phrase; for each disyllable, one consonant was a “test consonant” and the other two were controls. The test consonant was systematically varied with respect to voicing, stress and position‐in‐disyllable. Vowels in the disyllable were also varied systematically within the stressed syllable, and included /i/, /l/, u/, and /æ/. Preliminary analyses show that for some subjects, the dorsal stops are affected by stress and position differently than are the apicals and bilabials.

ISSN:0001-4966    

DOI:10.1121/1.2017212

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

Siegel, Pick, Olsen, and Sawin [Developmental Psychology12, 255–261 [1976)] found that young children decrease their vocal intensity less in response to sidetone amplification than adults. Perhaps when the child alters his vocal intensity, the acoustic cues accompanying the change differ from those available to the adult speaker. The present study was designed to determine whether the acoustic cues for vocal loudness and effort are the same in child and adult voices. The study is a replication of a study done with an adult speaker by Brandt, Ruder, and Shipp [J. Acoust. Soc. Am.46, 1543–1548 (1969)]. Children and adults repeated a sentence at seven intensity levels from 65 to 95 dB SPL. Adult listeners heard the sentences in a normal condition (as originally produced], with effort constant and intensity varying and with effort varying and intensity constant. Listeners rated the loudness and effort of each sentence. Preliminary results indicate that cues for loudness and effort are present in the speech of children as well as adults.

ISSN:0001-4966    

DOI:10.1121/1.2017215

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

Monaural pitch‐intensity functions were obtained in both ears of observers at half‐octave frequencies from 250 to 2000 Hz. For a given subject, the form of individual pitch‐intensity functions was often nonmonotonic and usually different in the two ears. Predictions derived from these pitch‐intensity functions were compared with several pitch‐shift phenomena, including amount of binaural diplacusis (as a function of intensity) and pitch shift of a tone in the presence of a higher intensity tone (as a function of frequency/intensity differences and phase). The latter phenomenon was compared under the assumption that the reduction in masking effectiveness of the lower intensity tone, caused by the presence of the higher intensity tone (as deduced from nonsimultaneous masking measurements), is equivalent to a reduction in intensity. Data from the binaural diplacusis measurements agreed well with the predictions derived from the pitch‐intensity functions. [Research supported in part by an NIH postdoctoral fellowship; portions were performed at the Research Laboratory of Electronics, MIT.]

ISSN:0001-4966    

DOI:10.1121/1.2017221

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

Discrimination of pitch for very brief tonal stimuli was measured in a two interval forced choice experiment in which experienced subjects were required to select the stimulus complex that contained acoustic events more disparate in pitch. Within each complex a comparatively long (750 ms) standard tone was followed by a 750 ms interstimulus interval and a brief comparison tone of variable frequency and duration (2, 4, 6. or 8 cycles). Frequencies used for the standard tone were 125, 250, 500, 1000, and 2000 Hz. All stimuli were matched for loudness. Analysis of performance indicates an interaction between number of cycles in the brief tone sample and frequency of the standard tone. Patterns of errors are considered in relation to spectral and periodicity models of pitch perception.

ISSN:0001-4966    

DOI:10.1121/1.2017223

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

Echolocating bats (Eptesicus fuscus) can detect jitter in the arrival‐time of sonar echoes as small as 500 ns. These bats could thus detect fluttering motions of prey resulting in displacements in range as small as 100–200 μm The range‐axis acoustic image of a planar target corresponds to the half‐wave‐rectified crosscorrelation function between the bat's broadband FM sonar transmissions and echoes.Eptesicuscan perceive echo phase information as would be encoded by phase‐locked discharges to excitatory half‐cycles of transmission and echo waveforms, which cover the frequency span from 25 to 100 kHz. Ambiguity in echo arrival‐time perception occurs for time‐separations corresponding to small integer multiples of average signal periods. The time‐domain neural crosscorrelator required here for extracting periodicity in sonar sounds and echoes has the desirable properties of recovering harmonic‐interval or “missing fundamental” periods in complex sounds and extraction and representation of periodicity information potentially for pitch perception. The data indicate that phase‐coding occurs in the auditory systems of bats at very high stimulus frequencies.

ISSN:0001-4966    

DOI:10.1121/1.2017233

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

The amplitudes of inaudible subjective signals are estimated using the monaural tone‐on‐tone masking procedure. These inferences are based upon three major assumptions: phase‐locked generation of subjective signals, vector summation between a subjective and acoustic tone, and the independence of the distortion from the sensitivity processes. Accordingly, any shift in sensitivity without an accompanying change in distortion levels should produce quantifiably predictable variations in the measured phase‐amplitude effects. Since the assumptions would most likely be violated at low frequencies, this prediction has been tested with a 250‐Hz masker, and comparisons of relatively long‐ versus short‐duration thresholds for a 500‐Hz maskee (probe). Observed decreases in phase‐magnitude effects with increasing losses in sensitivity follow predictions. These findings: (1) support the validity of the estimation procedure among subjects with normal hearing, (2) suggest a control condition important in estimating subjective tones among abnormal‐hearing subjects, and (3) have implications for inferring the origins of the monaural phase effects widely observed with inharmonic and harmonic probe tones of relatively high intensity. [Work supported by NIH and the Department of Otorhinolaryngology, University of Michigan Medical School.]

ISSN:0001-4966    

DOI:10.1121/1.2017244

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

We sought to demonstrate the stimulus‐like nature of combination tones by means of a simultaneous masking paradigm. Three musically‐sophisticated listeners were instructed to adjust the level of pure tones at various frequencies to just mask a pulsing pitch corresponding to a tone at 1200 Hz and 20 dB SPL. This pitch was produced by four stimulus conditions: (1) a pulsing tone at 1200 Hz; (2) af2−f1condition for which a continuousf1= 1900 Hz and a pulsingf2= 3100 Hz; (3) a 2f1−f2condition for which a continuousf1= 1650 Hz and a pulsingf2= 2100 Hz; and (4) a 2f1=f2control condition with a pulsing tone at 1200 Hz and a continuousf1= 1650 Hz. A common trend was exhibited across subjects. The low‐frequency slopes of the four tuning curve conditions were equivalent. The high‐frequency slopes were similar but were sometimes contaminated by interactions between the masker and the primary tones in conditions 2, 3, and 4. Condition 1 exhibited the steepest high‐frequency slope. These findings provide graphic demonstrations of the stimulus‐like nature of combination tones and of a similarity between odd and even order distortion products. [Work supported by NINCDS Grant NS03856.]

ISSN:0001-4966    

DOI:10.1121/1.2017248

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

A new and canonical approach to scattering problems in linear random media, including interfaces, is described, which incorporates the “classical” continuum theories (Eckart, Tatarskii, Tolstoy, and Clayet al.), the more recent FOM (Faure‐Ol'shevskii‐Middleton) theory, and the strong‐or multiple‐scatter interactions (Tatarskiiet al.) which can occur in atmospheres and oceans. Random moving media and random interfaces are readily included, as are varieties of different media characteristics, such as radiative and relaxation absorption, random indices of refraction, internal waves, diffusion, etc. Exact (feedback) operational solutions (FOS), where concepts of modern control theory extended to four‐dimensional feedback networks are indicated, are here introduced, along with the detailed statistics of the interactive elements in the equivalent FOR (feedback operational representation) and Feynman diagrams and various explicit approximations. The new approach, using generalized random point processes, provides also an anatomy of the scattering elements and their interactions. The general results are illustrated in detail by an explicit calculation of the general covariance of the random moving ocean surface. An example of strong volume interactions is also included. [Work supported by the Office of Naval Research Code 222.]

ISSN:0001-4966    

DOI:10.1121/1.2017251

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP

摘要:

The effect of multiple coherent acoustical scattering by a perfectly rigid, slightly rough surface can be represented by a “small roughness” boundary condition due to Biot. Using normal coordinates, this allows one to obtain simple, closed form solutions for the scattering of spherical impulses, for either isotropic or anisotropic surface roughness [I. Tolstoy, J. Acoust. Soc. Am. (in press)]. These results can be extended to the case of rough interfaces between media of different densities. Of particular interest here is the possibility of a boundary—or surface—wave travelling along the interface, and of amplitude proportional to the logarithmic density increment between the media. [Work supported by ONR.]

ISSN:0001-4966    

DOI:10.1121/1.2017256

出版商:Acoustical Society of America    

年代:1979

数据来源: AIP