bluuebunny/crossref_metadata_2025_split huggingface dataset:
Basis for the Acoustical Study of Singing
Authors: Fry D. B. , Manén Lucie 
Published: September 2005

A systematic classification of the tones which singers produce is necessary as a basis for spectrographic and for x-ray studies of singing. A three-dimensional system is proposed in which tones are classified according to (1) the type of voice, (2) the mood which the singer expresses, and (3) the vowel which is articulated.
Preliminary experiments suggest that acoustic differences (apparent in spectrograms) may be found regularly correlated with the differences of voice, mood and articulation covered by the system of classification.
Isolation from Vibration with a Mounting Utilizing Low- and High-Damping Rubberlike Materials
Authors: Snowdon J. C. 
Published: September 2005

The dynamic mechanical properties of rubberlike materials have been briefly reviewed. The value of a mounting composed of a low- and a high-damping rubber in parallel is in this way made apparent. Expressions have been derived from which the ability of the so-called parallel mounting to isolate vibration from any nonrigid foundation may be determined, if the mechanical impedance of the foundation is known.
One- and two-stage mounting systems have been considered. To compare their performance, the mechanical impedance of a damped beam has been employed to simulate the behavior of a nonrigid foundation. It is shown that the parallel mounting suppresses resonant motion at the natural frequencies of the foundation and the mounting systems with similar effectiveness to the high-damping rubber, yet provides the greater isolation at other frequencies. The isolation afforded by the mounting is, in fact, often comparable to that which the low-damping rubber affords.
Ultrasonic Propagation Measurement in Sea Water up to 400 kc
Authors: Hashimoto Tomiju , Kikuchi Yoshimitsu 
Published: September 2005

The propagation characteristics of ultrasound in sea water and its ultrasonic reflection loss on the sea bottom or on fish schools must be studied for both the design and the practical operation of echo sounders, fish finders, and SONAR's. This paper shows a practical method for this study, together with the results of measured propagation characteristics in both vertical and horizontal directions, as well as the ultrasonic reflection loss on the sea bottom and on fish schools, using 28, 50, 200, 300, and 400 kc.
The propagation attenuation in a direction vertical to the sea surface is the result mainly of spherical divergence, but the attenuation in a horizontal direction is caused partly by absorption as well. This absorption becomes larger at higher frequencies: in fact, the results of experiments show that the absorption is 10–20 db/km at 28 kc, 37–50 db/km at 200 kc, and about 120. db/km at 400 kc. The reflection loss of the ultrasound at a fish school decreases as frequency increases. On the contrary, the reflection loss of the sea bottom increases as frequency increases. At 200 kc, therefore, the echoes from ground fishes sometimes become stronger than that from the sea bottom.
On the Fusion of Sounds Reaching Different Sense Organs
Authors: Broadbent D. E. , Ladefoged Peter 
Published: September 2005

A simple place theory of hearing raises the problem that several mixed harmonics may be attributed by the listener to their appropriate fundamental frequencies: the recognition of a vowel sound in the presence of other sounds requires that the formants of the vowel be detected as such and not classified with the other sounds. Thus, the neural message from a particular part of the basilar membrane probably conveys in some way information on the fundamental frequency, to a harmonic of which that part of the membrane is responding. The problem of fusion of sounds on the two ears is merely an extension of the problem of fusion of different frequencies in one ear.
It is shown that synthetically produced speech will fuse when the first formant is presented to one ear and the second to the other, but it will not do so if the formants are given different fundamental frequencies. Even when both formants are given to the same ear, the latter condition fails to fuse. A further experiment with sustained formants shows that binaural fusion is not explained by the identity of some of the Fourier components on the two ears.
Propagation of Plane Sound Waves of Finite Amplitude in Nondissipative Fluids
Authors: Blackstock David T. 
Published: September 2005

An extensive theoretical treatment is presented of the problem of plane progressive sound waves (simple waves) produced by continuous, high-amplitude motion of a piston in a lossless, semi-infinite tube. The fluid in the tube is assumed to be nondissipative; liquids as well as perfect gases are considered. The analysis is given in both Eulerian and Lagrangian coordinates. Earnshaw's exact solution in parametric form is first given for arbitrary piston motion. Special attention is then given to the case of sinusoidal piston motion. Approximate but explicit power- and Fourier-series solutions for this case are derived from the exact solution. A low-amplitude nonlinear theory of simple waves is proposed. In this theory nonlinear effects are considered in a simple yet general manner.
A brief analysis of shock formation is also given. It is shown that the generally accepted formula for the distance at which the shock forms when the piston motion is sinusoidal is rigorously correct only under very special circumstances.
Acoustical and Organ Design for Church Auditoriums
Authors: Rienstra Albert R. 
Published: September 2005

The acoustical design of a church auditorium is of equal importance to that of the architectural design. It is essential, then, that the acoustical design follow the principles of projecting sound from the source to the listeners with maximum fidelity both for the listeners and for the performers. Church acoustics has varied from the dead, low reverberent type at one extreme to the excessively reverberant type at the other extreme. In between these extremes there is a range of good listening conditions for music and speech, for all types of liturgy. Longer reverberant times than usual are recommended for small and medium size auditoriums. The enhancement effect of reverberation on musical tones is shown to be related to the optimum reverberation characteristic. A new design of church auditorium is submitted which is interesting in its novelty, and is still practical from a modern architectural point of view.
Organ design has passed through extremes such as the pure romantic and the baroque. Either in its extreme is undesirable for general church use. Space requirements for organs and some principles of organ design including the design of mixtures to meet any reasonable acoustic condition are given. This paper is given to stress the musical point of view of church design to the acoustician and architect so that extremes in acoustics will be avoided in the future.
Free-Field Threshold Shift and Temporary Threshold Shift Reduction as Measures of Efficiency of Ear Protective Devices
Authors: Fletcher J. L. , Loeb M. 
Published: September 2005

The attenuation of two different earplugs and a helmet was measured by a procedure combining the free-field threshold shift and the Békésy threshold tracking methods. Subjects were then exposed to impulse noise which would produce between 12 and 64 dB TTS at 6000 cps unprotected and their TTS was subsequently measured after identical exposure during which they wore the protective devices. Following this the subjects were exposed unprotected to continuous noise which would produce a TTS at 6000 cps within ±6 dB of the TTS they experienced after their unprotected exposure to the continuous noise. Finally, they were exposed to the same continuous noise while wearing the protective devices, and their TTS following exposure was determined.
It was found that the helmet afforded significantly less attenuation of low-frequency sound than the ear plugs and roughly the same amount at higher frequencies. The three devices were found to be equally effective in eliminating the TTS following exposure to the continuous and impulsive noise. While the data did not lend themselves to definite conclusions regarding susceptibility to impulse and continuous noise, it appeared that susceptibility to one type of exposure was not necessarily significantly correlated with susceptibility to the other.
Effect of Phase on the Quality of a Two-Component Tone
Authors: Craig James H. , Jeffress Lloyd A. 
Published: September 2005

Listener responses to monaurally presented two-component stimuli (a 250-cps tone and its octave, at various intensities and phase relations) reveal striking individual differences and unexpected patterns. With certain pairs of these stimuli, that stimulus which is consistently judged higher in pitch (or louder or purer) by one subject is just as consistently judged lower (or softer or less pure) by another. When the intensity of one of the stimulus components and the phase angle between the components are held constant, reversals of phase of the entire stimulus become discriminable as soon as the intensity of the second component is increased a little above threshold. With certain combinations, as the second component is further increased, phase discrimination for one subject reaches a maximum, decreases to chance, and then increases again. For another subject under the same set of conditions, phase discrimination does not fail, but rather, monotonically increases.
No single explanation accounts for the subjects' patterns of responses and for their sensory experiences. Rather, it seems that two or more of several suggested mechanisms are involved.
Frequency-Correlation Functions of Frequency Responses in Rooms
Authors: Schroeder M. R. 
Published: September 2005

A mathematical study of the random interference of sound waves in large rooms requires statistical methods. “Statistical wave acoustics” is based on the random interference of many simultaneously excited normal modes of a room. In general, the random interference takes place for frequencies above 2000 (T60/V)12, where T60 is the reverberation time (in sec) and V is the volume (in m3) of the room. In the statistical theory, frequency responses between two points in a room are treated as random functions. The probability distributions, correlation functions, and “spectra” of these random functions are determined by physical parameters such as the distance between source and receiver, the volume and reverberation time of the room (or distribution of reverberation times), etc.
In this paper, correlation functions of frequency responses are derived for rooms with uniform reverberation time, and negligible direct sound transmission between source and receiver. Analytic formulas for the following frequency correlation functions are found: the autocorrelation functions of the real and imaginary parts, the modulus and the squared modulus of the frequency response, and the cross correlation function between real and imaginary parts of the frequency response.
The significance of these correlation functions in room acoustics is discussed. Measurement of the autocorrelation function of the real (or imaginary) part of the frequency response allows a precise determination of the distribution of reverberation times. The autocorrelation function of the modulus (or squared modulus) determines the required frequency shift in public address systems to improve their stability. For measurement of electroacoustic transducers in reverberation chambers, optimum bandwidths of noise or warble tones are obtained.
Propagation in an Infinite Elastic Plate
Authors: Sherwood J. W. C. 
Published: September 2005

At any single frequency an arbitrary force distribution in an infinite elastic plate must be expressible as a superposition of the plate's eigenvibrations. Since the force distribution may be varied in an infinite number of ways it follows that the plate must possess an infinity of eigenvibrations. Previous work has shown the existence of only a finite number, each being defined by a real propagation constant (unattenuated vibration: finite phase velocity) or an imaginary propagation constant (exponentially attenuated vibration: infinite phase velocity). This investigation yields the complementary infinity of eigenvibrations possessing complex propagation constants (exponentially attenuated vibrations: finite phase velocities). The probable structure of the complete eigenmode system in the low-frequency range has been hypothesized for a plate material with a Poisson's ratio of 0.31. The qualitative variation of this structure with changes in Poisson's ratio may be readily conjectured.
The utility of the complex eigenvibrations is enhanced by transforming them into an equivalent set, each member of which is constant in phase throughout the plate. These reformulated eigenvibrations are unique in that they possess an exponential amplitude variation along the plate together with a superimposed sinusoidal variation.
Sound Radiation of a System with a Finite or an Infinite Number of Resonances
Authors: Skudrzyk Eugen 
Published: September 2005

The sound field generated by a composite vibrator consists of a wattless near field that decreases very rapidly with distance and an energy-carrying radiation field. For radiators more than half a wavelength apart, the sound fields are spatially incoherent. The radiation field of a complex sound generator can therefore be computed by adding up the energy contributions of its various radiating elements. The radiating elements can be grouped as vibrators that are small in comparison to the wavelength, vibrators without nodal lines that are large in comparison to the wavelength, and vibrators with a nodal line pattern.
The radiation resistance of vibrators without nodal lines can, for most practical purposes, be stated with sufficient accuracy in terms of that of the equivalent sphere. The sound radiation of vibrators with nodal lines can be attributed to two causes. For the low-order modes of vibration, the contributions of the zone of positive and negative amplitude do not compensate one another entirely, and the radiation resistance, though small, is different from zero. Such modes may therefore be expected to contribute to the sound pressure if they are excited in their resonance range. For the high-order modes compensation is complete, but a point force or a force distribution along a line or over a finite area also excites to forced vibrations many low-order modes with very few nodal lines. Since the distance between the nodal lines is greater than the acoustic wavelength in the surrounding medium, the radiation impedance for these modes is very nearly equal to ρc. Since these modes are forced to vibrate at frequencies above their resonant frequency, the resistive component of their impedance being negligible in comparison to the reactive component, this sound pressure is independent of the damping of the system. The radiation impedance is computed for the cases mentioned.
Effect of Pressure on Ultrasonic Relaxation in Liquids. II
Authors: Litovitz T. A. , Carnevale E. H. 
Published: September 2005

Ultrasonic absorption and velocity in acetic acid and triethylamine were measured up to pressures of 3280 kg/cm2. The results show that the relaxation frequency in each liquid is independent of pressure to within experimental accuracy (±5%). The pressure data confirm the assumption of Heasall and Lamb that the loss in triethylamine is a rotational isomeric effect. The results in acetic acid are in agreement with the predictions of the monomer-dimer theory.
Comparison with previous results in carbon disulfide and glycerol shows that, depending upon the mechanism, increasing the pressure can cause the relaxation frequency in a liquid either to increase, decrease or remain constant. It appears that the pressure dependence of the relaxation frequency can be useful in distinguishing the type of relaxation present.
Isotopic Techniques in the Study of the Sonochemical Formation of Hydrogen Peroxide
Authors: Del Duca Michael , Yeager Ernest , Davies M. O. , Hovorka Frank 
Published: September 2005

Isotopic techniques involving oxygen-18 have been used to study the processes involved in the sonochemical formation of hydrogen peroxide during cavitation in oxygen-saturated solutions. Both tracer and equilibration experiments were carried out in an all glass system with converging ultrasonic fields providing maximum intensities of 103 w/cm2 at frequencies of 600 and 800 kc/sec. In oxygen-saturated water, one-third of the hydrogen peroxide oxygen was found to be derived from the oxygen gas while in solutions containing 30% (by volume) methanol, all of the peroxide oxygen was derived from the oxygen gas. In both cases, the oxygen molecule appears to be incorporated as a unit in one peroxide molecule without formal cleavage of the O - O bond.
Conditions associated with ultrasonically produced cavitation appear sufficient to dissociate water into H and OH and to rupture the C - H bond in organic molecules such as methanol but not sufficient to dissociate molecular oxygen. The oxygen molecule is involved in secondary reactions with hydrogen atoms, and hence, contributes to the formation of hydrogen peroxide. The experimental results can be explained most readily in terms of the large temperature rises which are presumed to occur within cavitation during compression but do not exclude electrical phenomena within the cavitation bubbles as a possible mechanism for the dissociation processes.
Semantic Approach to the Perception of Complex Sounds
Authors: Solomon Lawrence N. 
Published: September 2005

In an attempt to derive a limited number of descriptive adjectives with which to characterize passive sonar sounds, 50 U.S. Navy sonarmen (median sonar experience of one year) rated 20 different passive sonar sounds on 50 seven-point scales defined by polar-opposite adjectives (e.g., heavy-light). The intercorrelations between scales (calculated over both subjects and sounds) were factor analyzed by the Thurstone complete centroid method. Seven interpretable orthogonal factors (accounting for approximately 40% of the variance of judgments) were extracted from the data.
The generality of the methodology for psychological research on auditory perception is considered and suggestions for research along these lines are presented.
Arrays for the Investigation of Ambient Noise in the Ocean
Authors: Anderson Victor C. 
Published: September 2005

A discussion of the important parameters to be considered in the use of directional arrays for the study of noise fields in the ocean leads to specialized array designs. Some properties of circular and spherical arrays composed of omnidirectional elements are presented. Consideration of these properties leads to an optimum selection of geometry and element spacing for each of two cases: a distributed noise source, and a set of point noise sources.
The calculation of directivity index for a spherical array is carried out by the use of the space-correlation functions of an isotropic noise field.
The measured, broad-band directivity pattern of a model circular plane array as a function of frequency is also shown.
Attenuation of Sound in Lined Air Ducts
Authors: King A. J. 
Published: September 2005

Theoretical predictions of the performance of silencers are apt to be difficult and unreliable, so experimental results are often very valuable.
A previous paper contained curves giving the attenuation of sound with frequency in lined ducts of various widths and thicknesses of lining of rock wool. Subsequent experience has shown the need for an extension of these curves to cover thicker linings and splitters, and advantage has been taken of an opportunity to obtain further data on 16-in. splitters and air channels. New curves including these data are given for a 50% space factor, together with an extrapolation to 32-in. splitters. Thicknesses greater than 16 in. are unlikely to be used unless frequencies lower than 100 cps are important. For covering very wide frequency bands two-stage filters are recommended.
Temporary Threshold Shift and Masking for Noise of Uniform Spectrum Level
Authors: Miller James D. 
Published: September 2005

This experiment was designed to test the hypothesis that differences in the effective noise level from one critical band to the next can account for the typical audiogram showing the temporary threshold shift which results from an exposure to noise of uniform spectrum level.
For equal masking, or (B+K−β0), the greatest losses were found at the highest frequencies and the smallest losses at the lowest frequencies. However, the hypothesis implied that for equal masking all frequencies would show equal losses.
Further analysis revealed that when the data for temporary threshold shift were plotted against the quantity (B+2.7K−β0), the points for all test-tone frequencies fell on a common curve.
Torques Due to Acoustical Radiation Pressure
Authors: Maidanik G. 
Published: September 2005

A general expression for the torque on an object due to acoustical radiation pressure is derived by an approach similar to that used by P. J. Westervelt to derive the general expression for the force.
The general expression is then specialized to plane waves incident in an arbitrary direction. The simplification which is obtainable in the case of disks is also discussed.
Effect of Divalent Ion Substitutions on the Magnetomechanical Properties of Nickel Ferrite
Authors: Ferebee S. F. , Davis C. M. 
Published: September 2005

Magnetostrictive properties of cobalt-substituted nickel ferrous-ferrite were investigated to determine its suitability for use in electromechanical transducers. Toroidal samples were sintered at 1400°C and cooled by quenching in air. The following parameters were measured and compared with the corresponding parameters of previously investigated magnetostrictive materials: electromechanical coupling coefficient, reversible permeability, dynamic magnetostrictive constant, maximum stress, and the product of characteristic frequency times the thickness squared.
The results of the investigation indicate that a ferrite having the formula (NiO)1−x−y(CoO)x(FeO)y(Fe2O3) with 0.015 ⩽ x ⩽ 0.04 and 0.02 ⩽ y 0.065 moles per mole of ferrite meets the requirements for transducer applications. The electromechanical coupling coefficient for this range of compositions varies from 0.28 to 0.37. The value of the characteristic frequency times the thickness squared (4200) is approximately 1700 times that of nickel. The maximum stress increases with ferrous iron, reaching a value of 68×106 dynes/cm2 for 0.06 mole of FeO per mole of ferrite as compared with 32×106 dynes/cm2 for no ferrous iron.