摘要:

An underwater sound velocity meter, which makes continuous recordings of the velocity of sound in the ocean as a function of depth, is described. A phase comparison system of measurement is employed at 500 kilocycles. Several velocity and temperature records are given for comparison.

ISSN:0001-4966    

DOI:10.1121/1.1907291

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

摘要:

A method of measuring the velocity of sound in liquids by determining the critical angle for the sample and a known liquid is described. The method has been used to measure the velocity of sound in glycerol. The velocity at 7.5 mc and 25°C is 1964±10 m/sec. The velocity for glycerol‐water mixtures is also reported.

ISSN:0001-4966    

DOI:10.1121/1.1907292

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

摘要:

It is shown that for a special value of the Prandtl number the Stokes‐Kirchhoff equation governing the propagation of sound in a fluid is factorizable even for complex values of the heat conductivity and specific heats. A solution allowing for the dispersion due to both translational and thermal relaxation is thus obtained in simple form for this special case which, however, is representative of many gases with considerable accuracy.

ISSN:0001-4966    

DOI:10.1121/1.1907293

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

摘要:

A method of loudness scaling is presented for obtaining a true ratio scale of loudness. Two separate loudness functions are required, one based on equisection judgments and the other based on fractionation judgments. Interrelation of these two scales allows determination of all constants necessary for a ratio scale. The method provides validation of the assumptions underlying its use. Experimental data are also presented which show that (1) the method is valid for individual observers; (2) differences between loudness scales of different observers are considerably reduced with the method; and (3) the loudness function obtained with this method is much flatter than the standard scale now used. It is then shown that this new loudness scale is in better agreement with other data on equal loudness intervals than the standard scale. It is also shown that this scale is in agreement with monaural‐binaural loudness data and data on loudness of multicomponent tones.

ISSN:0001-4966    

DOI:10.1121/1.1907294

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

摘要:

This investigation was designed to study the correlation between behavioral audiograms and recordings of cortical potentials in experimentally deafened cats. Cortical thresholds were defined as the minimum intensity of tone pulses capable of eliciting strychnine potentials. Curves expressing threshold elevation with respect to normal animals were prepared for both the behavioral and cortical responses; these graphs were proportioned in accordance with the anatomical frequency scale and displayed above charts of cochlear histopathology. A mean value of 3.0‐db greater loss for the behavioral test was obtained when the differences between corresponding pairs of behavioral and cortical threshold elevations at all frequencies in all animals were averaged algebraically. The standard deviation of this collection of threshold differences was 17.4 db. Hypotheses advanced to explain the discrepancies include the effects of: (1) uncontrolled physiological variance in the cortical recording procedure; (2) the fact that the absolute cortical threshold exceeds the absolute behavioral threshold by 30 to 40 db; (3) the use of an abrupt onset for the cortical tone pulse. It is concluded that the cortical test is the most practical and descriptive electrophysiological indicator of threshold cochlear function presently available although it cannot be considered a precise substitute for behavioral threshold determinations.

ISSN:0001-4966    

DOI:10.1121/1.1907295

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907297

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

摘要:

The problem of sound transmission through a membrane stretched across a duct is analyzed rigorously. The integral equation for the velocity distribution of the membrane is set up and studied in the special case of a circular cylindrical tube. Equivalent circuits for the membrane are shown for the frequencies around the resonances and the antiresonances of the membrane. High transmission loss is commonly associated with a large mass, but it is clear that it can also be obtained with very little mass if stiffness rather than mass provides the high impedance.

ISSN:0001-4966    

DOI:10.1121/1.1907298

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907270

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907271

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP

摘要:

The average energy spectrum of the reflection from an array of randomly located point scatterers has been calculated. It is shown that this spectrum is proportional to the square of the sum of the individual scatterer amplitudes for wavelengths large compared to the extent of the array and that it is proportional to the sum of squares of the individual amplitudes for wavelengths small compared to the array extent.

ISSN:0001-4966    

DOI:10.1121/1.1907273

出版商:Acoustical Society of America    

年代:1954

数据来源: AIP