bluuebunny/crossref_metadata_2025_split huggingface dataset:
Notes on the Transmission of Sound Through Plates
Authors: Fay R. D. 
Published: September 2005

A relatively tractable expression for the transmittivity of steel plates immersed in a fluid medium is formulated. Criteria for total transmission and total reflection are inherent in the expression.
An investigation of the discrepancies between calculated and observed transmittivity indicates a probability that the assumption of negligible losses associated with shear waves in steel is not tenable.
Recent Work on Violins
Authors: Saunders F. A. 
Published: September 2005

(a) Loudness-frequency curves of violins disclose peaks caused by natural vibrations of the body and of the inner air. “Overtone peaks” occur when a natural vibration coincides with one of the partials of the tone. Shifting the frequencies of the natural vibrations is possible and can produce a more even distribution of strength.
(b) The volume of tone is very sensitive to the thickness of the top plate along the line where it is attached to the rest of the body. Thinning a groove part way around the top has produced marked improvements in several instruments.
(c) The air inside the box produces one noticeable peak only in the loudness curve. Tuning forks placed in front of the f-holes produce responses but they are the result of body vibrations.
(d) Experiments on f-holes show that long ones are somewhat better than short, and also that the main function of the bass-bar is to carry vibrations from the active foot of the bridge to the wider areas.
(e) Resonating strings reduce loudness rather than increasing it. Interesting phase differences occur between strings, or the inner air, or parts of the body.
(f) A string gives more tone when the others are relaxed.
A Scale for Specifying Frequency Levels in Octaves and Semitones
Authors: Moon Parry 
Published: September 2005

A new system of specifying frequency level is proposed. It utilizes the logarithm (base 2) of the relative frequency, expressed in duodecimal notation. In this way the designation of musical intervals and musical scales is related directly to frequency, yet the numbers repeat in each octave and the semitones of the equitempered chromatic scale are expressed exactly as 0.100, 0.200, 0.300, ⋯.
The new notation is applied to the macrodesignation of semitones and octaves, and to the microdesignation of true intervals and of Pythagorean and Ptolemaic scales. A slide rule is developed to allow easy visualization of the relations among musical intervals.
Patterns of Cochlear Adaptation at Three Frequency Regions
Authors: Harris J. Donald , Rawnsley Anita I. 
Published: September 2005

Auditory adaptation was determined four observers to 100-, 1000-, and 4000-cps tones at 30-, 50-, 70-, and 90-db loudness level. The spread of effect to closely adjacent frequencies was particularly examined. The method of adaptation was used to avoid the intrusion of beats in the simultaneous masking experiment.
Loudness patterns were drawn according to the method of Munson and Gardner, confirming and extending the earlier study. Within the region represented by the differential threshold, no especial peaking of the loudness pattern was found. For example, at 1000 cps, there was broad peak of ±10 cps.
From earlier experiments, adaptation is thought to be confined to the peripheral sense organ. According to this view, the present data would represent a stage in the process of handling frequency information, intermediate between the much broader amplitude patterns and the more precise operations the command of the nervous system.
Description of Some Mechanical Properties of the Organ of Corti
Authors: v. Békésy G. 
Published: September 2005

A short historical introduction is followed by a description of the technique for observing the organ of Corti in a lightly anesthetized guinea pig with the help of a slit lamp. The magnification was around 200 times, and stroboscopic illumination was used with a 1-kilowatt high pressure mercury-arc lamp. The relative stiffness of the Reissner's membrane, the tectorial membrane, the reticular membrane, and the Hensen cells were investigated with test needles. It was possible to demonstrate the earlier anatomical concepts of the stiffness of the reticular membrane and the pillars of Corti.
In order to obtain the high sensitivity of the ear, the stiff tissues of the organ of Corti must be mechanically matched (impedance matched) to vibrating energy. of the perilymph. It was found that the organ of Corti is very well suited to work as a transformer for shearing forces.
The difference between the vibration pattern of a series of resonators in the sense described by Helmholtz and the pattern of traveling waves is described. The actual observation of the membranes in the organ of Corti showed only traveling waves during stimulation with a pure tone.
For every given frequency there was one point along the basilar membrane where a transition in the vibration pattern occurred, and the more radial vibrations of the organ of Corti near the stapes went over into longitudinal vibrations on the wave front facing the helicotrema. The place of transition moves with the frequency of the stimulus. Finally, the different traveling waves which may run along an elastic pad like the organ of Corti are described, and their possible roles in the cochlea are discussed. This leads to some possible explanations of why the cochlea is coiled.
On the Measurement of Power Radiated from an Acoustic Source
Authors: Cady Walter G. , Gittings Curtis E. 
Published: September 2005

This paper describes an experimental test of the theory that the total force on an absorber receiving a beam of plane waves is a measure of the acoustic power generated at the source, provided that certain conditions are satisfied. The exponential decay in acoustic intensity is accompanied by a corresponding exponential increase in the force due to the hydrodynamic flow, as has been verified experimentally. The sum of these two forces, plus a possible further force that may exist at the emitting surface due to local hydrodynamic conditions or to a “pumping effect,” should be independent of the distance from the source to the absorber. The verification of this prediction is the chief result of the investigation. From the results it can also be inferred that the “pumping effect,” if it exists at all, is probably very small in liquids.
As absorbers, slab of ρc rubber, a 90° wedge, and a cavity radiometer were used.
The reacting force on the transducer was also measured, and found, within the limits of measurement, to be equal to that on the absorber. This result indicates that acoustic power can be measured by observing this reacting force without the need of an absorbing system.
Seismic Model Study
Authors: Howes E. T. , Tejada-Flores L. H. , Randolph Lee 
Published: September 2005

A method has been developed for studying seismic sound pulses in reduced scale models which simulate geophysical seismic exploration methods. Use is made of a tank of water for transmission of the acoustic wave from a source to a faulted limestone stratum and return to a pressure sensitive receiver.
Results obtained demonstrating the geometric aspects of the propagation, reflection, refraction, and diffraction of sound pulses are described and illustrated on accompanying plates.
Some Experiments on the Recognition of Speech, with One and with Two Ears
Authors: Cherry E. Colin 
Published: September 2005

This paper describes a number of objective experiments on recognition, concerning particularly the relation between the messages received by the two ears. Rather than use steady tones or clicks (frequency or time-point signals) continuous speech is used, and the results interpreted in the main statistically.
Two types of test are reported: (a) the behavior of a listener when presented with two speech signals simultaneously (statistical filtering problem) and (b) behavior when different speech signals are presented to his two ears.
Wave Motion in the Cochlea Caused by Bone Conduction
Authors: Zwislocki J. 
Published: September 2005

Psychophysical and physiological experiments have shown that a tone transmitted to the cochlea by bone conduction can be compensated by an airborne sound. From these experiments it has been deduced that the vibration pattern of the cochlear partition does not depend upon the path by which sound is transmitted to the cochlea. This hypothesis has been confirmed by direct observation of the vibration pattern in cochlea models and by measurements of cochlear microphonics. From both kinds of experiments attempts have been made to draw conclusions concerning the theory of cochlear dynamics.
In an effort to explain the fact that the vibration pattern of the cochlear partition is independent of the path by which the sound is transmitted to the cochlea, a mathematical analysis has been performed. First, by means of the hydrodynamic principle of continuity, it has been demonstrated that the vibration of the cochlear partition caused by a tone introduced into the cochlea either through the bony wall or through an artificial window can be canceled by a tone transmitted through the oval window, irrespective of the dynamic properties of the partition. Second, a general differential equation of hydrodynamic surface waves has been established, which shows that transverse waves are propagated along the cochlear partition every time there is a difference in pressure between the two sides. According to this equation, the wavelength is independent of the place at which the sound is introduced into the cochlea. Third, it has been deduced from Hamilton's principle of stationary energy that transverse waves in the cochlea must travel from the base towards the apex, irrespective of the location of the sound source. Hence, in agreement with the experiments, the mathematical analysis shows that the vibration pattern of the cochlear partition does not depend upon the way in which sound is transmitted to the inner ear. Furthermore, it shows that the introduction of sound through the bones or through an artificial window does not provide any new clues for the explanation of this pattern.
Second Viscosity Coefficient of Liquids
Authors: Karim S. M. 
Published: September 2005

It is known that the experimental value of the absorption of ultrasonic waves in most liquids is in excess of the theoretically calculated one. While attempts have been made to explain the discrepancy in different ways, a phenomenological approach is through the second viscosity coefficient.
Recently Eckart has discussed the streaming set up in a liquid when a beam of ultrasonic waves passes through it, and has shown that it is dependent on both the bulk and shear viscosities.
The conclusions arrived at from an experimental investigation carried out on the basis of Eckart's theory are:
1. The value of the ratio of second viscosity to shear viscosity is positive in conformity with the theory.
2. The agreement between experimental and theoretical values is closer in the case of pure liquids than in the case of solutions. For pure liquids the value of μ′, the second viscosity, appears generally to be greater than the value of μ, the shear viscosity, at ordinary pressures and temperatures.
3. The values of μ′ as obtained by experiment and as calculated from the excess sound absorption data are in fair agreement in the case of the liquids used.
4. In some solutions the two coefficients are either equal or the shear viscosity is the greater.
5. The values of μ′/μ obtained by independent workers with different methods are in fair agreement.
Although the anomalous absorption of sound may be accounted for by the second viscosity coefficient, more data are necessary before a final conclusion can be drawn as regards the precise mechanism of the sound absorption.
The Scattering of Sound in a Turbulent Medium
Authors: Kraichnan Robert H. 
Published: September 2005

The scattering of a sound wave in a medium undergoing shear flow confined to a finite region is investigated under the assumption that the total velocity field is everywhere small compared to the velocity of sound. Formulas are obtained for the angular distribution and frequency distribution of the scattered wave in terms of the four-dimensional Fourier transform of the shear velocity field.
Under typical conditions, the cross sections for the scattering of a plane wave of frequency ω by a shear flow of given scale and spatial structure are approximately of the form ω4M2, where M is a characteristic Mach number of the flow. The coupling between the shear and longitudinal velocity fields has a tensor character such the the scattering vanishes at 180 degrees and at 90 degrees. The spectrum of the scattered sound wave is very sharp in the forward direction and becomes broader at larger scattering angles.
Explicit expressions for the cross sections are obtained for the case of scattering from a region of isotropic turbulence. When the frequencies of importance in the turbulence are small compared to the frequency of the incident sound wave, the average differential scattering cross section can be expressed directly in terms of the energy spectrum of the turbulence.
Recent Advances in Hearing Aids
Authors: Hector L. Grant , Pearson Harry A. , Dean Neal J. , Carlisle Richard W. 
Published: September 2005

The experience gained in fitting a large number of impaired persons with hearing aids is presented, showing illustrative ranges of impairment between 30 and 100 decibels fitted with three progressively-powered hearing aids.
General features of such hearing aids are discussed, showing circuits and arrangements for peak clipping and automatic gain control.
The microphone and air and bone receivers are described, considering features developed for providing optimum reliability in service such as moisture proofing, and design arrangements providing miniaturization concomitant with ruggedness.
Dual-Stylus Ceramic Phonograph Pickup Development
Authors: Koren H. W. , Pearson H. A. , Klingener H. , Sabol R. W. 
Published: September 2005

The freedom from humidity and temperature limitations have made ferroelectric ceramics valuable type of transducer for phonograph pickups (originally designed for 78 rpm records). Two groove sizes now indicate the use of dual styli. A pickup structure is described in which dual styli are used hack-to-back on one lever. A mechanism provided on the bottom of the pickup whereby the stylus assembly can be turned over to present the proper stylus to the record. This structure imposes no dynamical limitations on the performance of the pickup, as the additional mass required for the second stylus is only a small percentage of the total mass, and no additional stiffness constraints are imposed on the system.
Reasonably flat characteristics have been obtained. In one commercial model a sensitivity of over one-half volt is achieved on microgroove records, with a frequency range to 10 000 cps with a tracking force of 6 grams for microgroove and 9 grams for standard-groove records.
Sound Velocity in Some Aqueous Solutions as a Function of Concentration and Temperature
Authors: Barthel Romard 
Published: September 2005

Precision sound velocity measurements are reported in sucrose solutions in the concentration range up to 3 molal, and in solutions of NaCl and Pb(NO3)2 up to 2 molal. Measurements were made at three temperatures—24.76°C, 40.37°C, and 59.60°C—using 15-Mc sound. For sucrose and NaCl the velocity vs molality relation is linear out to about 1 molal, where a slight decrease in slope sets in. For Pb(NO3)2 the velocity vs molality relation has a negative slope, and a rise from linearity is already evident at 0.5 molal.
A simple theory of the concentration dependence of the sound velocity in solutions is developed and correlated with experimental data.
The Backscattering of Sound from a Harbor Bottom
Authors: Urick R. J. 
Published: September 2005

When underwater sound strikes the bottom of the sea in shallow or deep water, a portion of its intensity is scattered back toward the source of sound. A study of the backscattering from the bottom as a function of pulse length, frequency, and tilt-angle at several locations in a harbor along the East Coast, was made by using a tiltable transducer mounted on a barge. The results are expressed in terms of quantity called the “scattering strength” of a unit area of bottom.
The results suggest that the backscattering of sound from a natural bottom is due more to its roughness rather than to the fact that it consists of sedimentary particles. Even at normal incidence the bottom of a sea or bay appears sufficiently rough so that little sound is returned by specular reflection. Some evidence in support of these conclusions is given.
Ultrasound and Medicine. A Survey of Experimental Studies
Authors: Herrick J. F. , Krusen Frank H. 
Published: September 2005

Experimental investigations indicate that ultrasound may prove useful for therapy, for diagnosis, and for biologic measurement.
Ultrasound, although it may be dangerous in unskilled hands, is an excellent agent for the structural heating of living tissues. The term “structural heating” is used to denote heating at abrupt interfaces.The living organism presents numerous abrupt interfaces.
Ultrasound promises to become a reliable diagnostic tool. Either the transmitted or the reflected ultrasonic energy can be used in this application. Tumors, gallstones, kidney stones, stones in the salivary glands, foreign bodies, and abnormal collections of fluid have been located accurately.
Preliminary observations on the use of ultrasound for certain biologic measurements are encouraging. Instrumentation for biologic measurement includes ultrasonic flowmeters, devices for measuring thickness of some tissue structures, and equipment for measuring the viscosity of blood.
Ultrasonic Spectrum of Cavitation Noise in Water
Authors: Mellen Robert H. 
Published: September 2005

The acoustic noise spectrum associated with the collapse of transient cavities produced by a stirring rod in water was measured in the frequency range 1–3500 kc. While the spectrum, in general, goes as f−2 above 1 kc, flat regions are found between 20 kc and 100 kc, and again above 500 kc to at least 3500 kc. If the flat regions are due to discrete random impulses, two time constants, τ1≃10−6 second and τ2&lt;10−8 second, may be obtained by using the criterion 2πfτ≃1, where f is the −3 db point beyond the flat region.
With intense cavitation, the acoustic level fails off and becomes erratic in the 600-kc region. Transmission measurements made through the cavitating volume show strong sound absorption, which appears to be caused by a cloud of small, stable bubbles.
An Artificial Voice and Miniature Anechoic Chamber for Hearing Aid Measurements
Authors: Carlisle Richard W. 
Published: September 2005

There is described an enclosure for a standard loudspeaker mechanism which provides a compact sound source or artificial voice. With a size slightly larger than a human head, the frequency range is 100 to 7000 cps. A simple and reproducible arrangement of damping felt gives unusual flatness.
This artificial voice can either be used in free space or with a small chamber arranged as an acoustic labyrinth, for testing microphones and hearing aids. In the chamber, calibrating microphone is mounted opposite the test microphone for continuous monitoring. Simple rc compensating networks are utilized to equalize the sound source for either free-space or labyrinth measurements.
An Acoustic Method for the Measurement of Vibration Amplitudes
Authors: Koidan Walter 
Published: September 2005

By means of a modification of the pistonphone, a technique has been developed to obtain the response of a capacitance type vibration pickup probe using the reciprocity calibration of a condenser microphone as a reference. The raised, center portion of a circular piston, driven by a barium titanate cylinder, projects into one end of a cavity, the shelf of the piston being located outside of the enclosure. A calibrated condenser microphone coupled to the other end of the cavity responds to the sound pressure developed by the piston. The output of an annular capacitance type vibration pickup, which detects the motion of the piston shelf, is compared with the generated microphone voltage. With the microphone removed from the cavity, the output of a capacitance probe located adjacent to the top surface of the piston is compared with that of the annular pickup. The probe response is computed from these measurements and the microphone response.
From considerations of checks by independent methods, an accuracy of about 0.5 db is indicated from 100 to 10 000 cps. Using a sensitive probe, vibration amplitudes as small as 10−9 cm have been measured with a comparable degree of accuracy.
Logarithmic Measure and the Decibel
Authors: Hall William M. 
Published: September 2005

A simple method of expressing the logarithmic measure of physical quantities is proposed, which is generally applicable to all quantities and avoids the use and misuse of the term decibel.
Editor's note.—It is believed that discussion and critical thought on this subject should be encouraged. and it is to this end that this Letter is published. The Editors do not necessarily concur with the views expressed.
The definition of the decibel and related units will be studied during the forthcoming revision of American Standard Acoustical Terminology Z24.1-1951 by Sectional Committee Z24. Suggestions (especially in the form of preferred wordings of definitions) are welcomed; address proposals to Chairman of Writing Group Z24.W-5, Robert W. Young. U.S. Navy Electronics Laboratory, San Diego 52, California.
Acoustic Impedance of a Right Circular Cylindrical Enclosure
Authors: Biagi Fernando , Cook Richard K. 
Published: September 2005

At low frequencies, the acoustic impedance of a right circular cylindrical enclosure (containing air, or other gases) is affected by the cooling effects of the walls. Analytical expressions for the temperature distribution have been obtained, and computations of the effect on the impedance are given in the form of plotted correction factors. These corrections are used in making absolute pressure calibrations of condenser microphones at low frequencies.
The solution presented for the average temperature distribution applies also to the heat-conductivity problem of a uniform volume distribution of sinusoidal heat sources, which are considered to be in phase, inside a cylindrical enclosure having isothermal walls.
Absorption and Dispersion of Ultrasonic Waves in Liquids
Authors: Parthasarathy S. 
Published: September 2005

Mr. Chairman and Friends: It gives me great pleasure to be amongst you on this great occasion when you are celebrating the Silver Jubilee Anniversary of the Acoustical Society of America. This has been made possible by the invitation extended to me by the Society and by the Government of India's deputing me to attend the function. It is indeed a pleasant duty to thank both the Acoustical Society of America and the Government of India for their generous gestures. And hereby I convey the greetings of India!
The subject I have chosen for a talk on this occasion is “The Absorption and Dispersion of Ultrasonic Waves in Liquids,” a subject in which I have been greatly interested in the past few years.