摘要:

Phase effects in a particular three‐component signal, consisting of the 9th, 10th, and 11th harmonic of 200 Hz were studied. The main interest was the effect of phase changes on the prominence of the residue pitch evoked by this signal. The prominence of residue pitch appears to be correlated to the acoustical power spectrum of the signal, modified by the internally generated combination tones. An estimate of this “internal spectrum” was obtained by means of a cancellation technique. Because of an interaction of combination tones and acoustical components, this “internal spectrum” is phase‐dependent. In this context de Boer's phase rule is reconsidered. The residue pitch seems to be most prominent if there are prominent lower harmonics in the “internal spectrum.” In general, subjective phase effects in this signal, which could be described as changes in timbre, seem to be dependent on changes in the “internal spectrum.”

ISSN:0001-4966    

DOI:10.1121/1.1914501

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

While partly influenced by critical bandwidth (CB), direct measures of auditory sensitivity such as pure‐tone masked threshold and frequency‐difference threshold reflect other factors as well. In an attempt to find a rapid direct estimation of CB, two experimental tasks were explored. The difference threshold for frequency modulation of a narrow stop band in a noise spectrum was found not to provide a good estimator as the task showed the variability over subjects usual with measures of performance level. The second task, threshold frequency difference required for a partly masked tone to achieve a pitch separate from that of a higher‐frequency masking tone, furnished absolute values and functions over frequency very similar to the classical CB.

ISSN:0001-4966    

DOI:10.1121/1.1914502

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

Equal loudness measurements are reported for six young normal‐hearing adults over a frequency range of 250 to 6000 Hz. The signals consisted of an exponentially decaying oscillatory waveform whose decay rate per cycle was constant with signal frequency. The results show a well‐defined relation between sound pressure for equal loudness and signal frequency. A mathematical expression for this relation is given and calculations based on it were consistant with the averaged data over a pressure range of 0.0001 to 100 μbars. With signals of the type employed sound pressure for most comfortable loudness was found to be independent of frequency.

ISSN:0001-4966    

DOI:10.1121/1.1914503

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

Utterances of two adults males were analyzed and synthesized by a fast Fourier Transforms method. Each of the two voices was synthesized in each of the twenty‐seven combinations of three levels each of rate, meanFØ, and variance ofFØ(a total of fifty‐four “voices” generated from two). The effects of the rate, meanFØ, and variance ofFØmanipulations, the interactive effects of rate and variance ofFØ, and the effects due to speaker were all statistically significant predictors of personality ratings given the voices. They accounted for 86%, 4%, 3%, 2%, and I% of the variance, respectively, in competence ratings and 48%, 1%, 6%, 1%, and 8% of the variance, respectively, in benevolence ratings. Increased speaking rate was found to decrease the benevolence ratings, and decreased rate was found to decrease competence ratings. Decreased variance ofFØwas found to decrease the ratings on both competence and benevolence. Increased meanFØin these male voices was also found to decrease competence and benevolence ratings.

ISSN:0001-4966    

DOI:10.1121/1.1914504

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

Morse code signals were presented dichotically to Morse code operators and to subjects who did not know Morse code. Morse code operators showed right ear superiority, indicating left hemisphere dominance, for the perception of dichotically presented Morse code letters. Naive subjects (i.e., subjects who did not know Morse code) showed right ear superiority, indicating left hemisphere dominance, (n.b.: same as Morse code operators) when presented with a set of dot‐dash patterns which was restricted to pairs including seven or fewer elements, counting dots and dashes each as elements. The list restricted to pairs with seven or fewer elements in all was presented to the naive subjects at two levels of intensity, but even though the overall accuracy changed, the direction and degree of asymmetry as measured by the left ear contribution to the total errors remained constant. When presented with a list that included longer stimuli, naive subjects showed left ear superiority, indicating right hemisphere dominance, the opposite of their result with the shorter stimuli. We hypothesize that pairs consisting of the Magical Number Seven or fewer elements are perceived with reference to the subparts of which they are composed, but that longer stimuli force naive subjects to adopt strategies involving the holistic qualifies of the stimuli. Therefore we speculate that the left hemisphere is specialized for processing the sequential parts of which a stimulus is composed. Analysis of the substitutions made by Morse code operators does not reveal a phonetic basis for the lateralization of the stimuli as perceived by them. Consideration of our findings in the light of other literature on lateralization suggests that language is lateralized to the left hemisphere because of its dependence on segmental subparts, and that this dependence characterizes language perception as distinct from most other human perception.

ISSN:0001-4966    

DOI:10.1121/1.1914505

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

Native speakers of English identified and then discriminated between stimuli which varied in voice onset time (VOT). One group of listeners identified a randomized sequence of stimuli; another group identified an ordered sequence of stimuli, in which stimuli from the VOT continuum were presented in a consecutive order. Half of theSsin each group then received one of two discrimination formats: the ABX discrimination test in which X was identified with A or with B, or 4IAX test of paired similarity in which two pairs of stimuli—one pair always the same and one pair always different—were presented on each trial. Noncategorical perception of the voicing distinction, reflected by an improvement in discrimination within phonetic categories, was obtained for the group of listeners who experienced both the sequential identification procedure and the 4IAX discrimination test. The results are interpreted as providing evidence for separate auditory and phonetic levels of discrimination in speech perception.

ISSN:0001-4966    

DOI:10.1121/1.1914506

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

A system using the Doppler shift of audible sound waves to measure atmospheric winds to heights of 1 km above the surface is described. Planned application of the device at a commercial airport required extensive transducer and antenna shielding to reduce the effect of ambient noise. Comparisons of winds measured by both the acoustic Doppler system and standard radiosondes indicate that high accuracy and resolution can be achieved, and that the wind profiles can be continually monitored with relatively simple ground based equipment.

ISSN:0001-4966    

DOI:10.1121/1.1914507

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

The frequency spectra of resonant vibration in disk plates ofPbTiO3piezoelectric ceramics were observed for diameter to thickness ratio (r) of 5 to 30 near the fundamental thickness extensional mode. The observed spectra could be classified into three groups of thickness mode and two groups of radial mode. For comparison, theoretical spectra for isotropic disk plate were also calculated for various Poisson's ratios (σ) of disk material on the basis of Gazis and Mindlin's theory. The calculations showed that the theoretical radial mode spectra can be divided into a strongly σ‐dependent group and a slightly dependent one, and also showed that the upper ends of terrace‐type spectra appear as a straight line at the cutoff frequency in a large‐rregion and may be corresponded to the thickness extensional mode. In fact, the fitting of the upper‐end spectra to the experimental thickness extensional mode by adjusting σ, gives not only qualitative agreement of all experimental spectra with the theoretical ones, but also the best quantitative agreement with the strongly σ‐dependent theoretical spectra. Thus, all observed spectra can be predicted nearly completely from the theory of isotropic disk plate by selecting a suitable equivalent σ which is 0.18 for the present anisotropic disk.

ISSN:0001-4966    

DOI:10.1121/1.1914508

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

An analytical study of the operation of electret transducers subject to relative displacements of the electrodes comparable to the thickness of the air gap (or air gaps) between electret and electrodes is presented. In particular, the relations between generated voltage and time history of the transducer capacitance are derived for transducers terminated by a combination of resistive and capacitive components. Following this analysis, graphical and numerical results for the shape and peak amplitude of the voltage response due to displacements with trapezoidal time dependence are presented.

ISSN:0001-4966    

DOI:10.1121/1.1914509

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP

摘要:

A multichannel acoustic emission monitoring system has been developed recently. The system possesses high sensitivity for the sound pressure level of the emission and is concerned with the frequency selection to overcome various background noise disturbances. The signal and data processing unit can process multiple acoustic emission events simultaneously for analyses. The cathode ray tube screen of a computer is used for a real time graphic display of the number of events at individual locations of the emission sources.

ISSN:0001-4966    

DOI:10.1121/1.1914510

出版商:Acoustical Society of America    

年代:1974

数据来源: AIP