摘要:

In this paper a theoretical and experimental treatment is given of guided sound wave transmission along circular cylinders of ideal liquid with various non‐dissipative boundary conditions. The field patterns, phase velocities, and cut‐off frequencies are calculated for the natural modes of propagation in the following cases: (1) liquid cylinder with rigid walls; (2) liquid cylinder with pressure‐release walls; (3) liquid cylinder embedded in infinite liquid; (4) liquid cylinder with liquid walls; (5) liquid cylinder with thin solid walls. The problem of determining the field produced by an arbitrary excitation in terms of the natural modes is also discussed.Experimental results are presented for cases (2) and (5) above. It is shown that the measured values of phase velocity are in agreement with those predicted by the theory.

ISSN:0001-4966    

DOI:10.1121/1.1906475

出版商:Acoustical Society of America    

年代:1949

数据来源: AIP

摘要:

The general form of the intensity function for the electrical responses of the cochlea is now well known. As we raise the intensity of a sound applied to the ear, the cochlear potentials rise at first in simple proportion to the intensity, and then at a high level, as the stimulus is elevated further, they cease to follow this simple relation and give a bending curve. From the first departure from linearity onward the responses rise more and more slowly in relation to the stimulus until at last they reach a maximum value, a value beyond which they actually diminish as the intensity is raised.So much of the form of the function is established on the basis of numerous experiments (see reference 2), yet there still are many details not yet worked out with exactness. The present study seeks in a measure to supply this lack. We have been concerned especially with the initial departure from linearity and the maximum value of the response for various frequencies over the tonal range. This information, as we shall show, has a pertinent application to the problems of the locus and spread of response over the basilar membrane.

ISSN:0001-4966    

DOI:10.1121/1.1906476

出版商:Acoustical Society of America    

年代:1949

数据来源: AIP

摘要:

The most important results of the determinations previously published on the adaptation of the ear to sound stimuli are briefly recapitulated. Adaptation is defined as the elevation of the auditory threshold by a previous sound stimulus. It may be determined by means of a short tone impulse (testing impulse) which follows the sound stimulus (stimulating impulse) causing the adaptation. The testing impulse is adjusted to the threshold value. By altering the interval between the stimulating and testing impulses, the curve of return adaptation, i.e., the return to normal sensitivity, may be ascertained. When plotted on a logarithmic db scale, this curve is approximately a straight line.New experiments have shown that the entire process of adaptation requires less than 0.4 sec. The return adaptation is complete within a few tenths of a second. After stimulation by a tone of 80 db above threshold intensity, return adaptation is complete after 250 μsec.The increase in adaptation is approximately proportional to the intensity of the stimulating tone when both magnitudes are expressed in db. With a sound impulse of 80 db above the auditory threshold, the adaptation reaches a value of 40 to 50 db.Binaural determination of adaptation, by leading the stimulating impulse to one ear and the testing impulse to the other, shows that adaptation is a monaural and therefore a peripheral process.A pure tone induces an elevation of the auditory threshold not only for its own frequency but also for neighboring ones. The adaptation spreads chiefly to higher frequencies than that of the stimulating tone at which it reaches a maximum. The maximum is more pronounced at high frequencies of the stimulating tone than at low ones.Comparative experiments between adaptation and masking demonstrate a far‐reaching similarity between the two processes. These show a similar behavior with respect to intensity and frequency. A quantitative comparison leads to the conclusion that masking depends chiefly upon the adaptation of the ear to sound stimuli.

ISSN:0001-4966    

DOI:10.1121/1.1906477

出版商:Acoustical Society of America    

年代:1949

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1906478

出版商:Acoustical Society of America    

年代:1949

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1906479

出版商:Acoustical Society of America    

年代:1949

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1906481

出版商:Acoustical Society of America    

年代:1949

数据来源: AIP