bluuebunny/crossref_metadata_2025_split huggingface dataset:
Certain Anomalies in the Theory of Air Column Behavior in Orchestral Wind Instruments
Authors: Redfield John 
Published: September 2005

Assuming the clarinet to be closed at its mouthpiece end, theory requires that only odd partials enter the composite tone produced, while analysis of the tone produced shows traces of all even partials, and Miller finds the twelfth partial the most intense of all. On the other hand, to explain the complete series of partials produced by the oboe, bassoon, saxophone, and brass instruments, it is assumed that these instruments are open at their mouthpieces, although these mouthpieces differ in no qualitative respect from the clarinet mouthpiece which is assumed to be closed.
These contradictions disappear, and the observed facts are explained, by recognizing the fact that no orchestral wind instrument is closed at its mouthpiece end, a closed end being necessarily defined as one which prevents the escape of air. All orchestral wind instruments are thus doubly open tubes producing the full series of partials, the relative intensities of the several partials being determined by the contour of the air-column walls in the several instruments. Thus the lower even partials are relatively weaker than the higher in the clarinet, while the lower and higher even partials of the French horn do not vary materially in intensity.
Design Considerations for a Simple and Versatile Electronic Musical Instrument
Authors: Miessner B. F. 
Published: September 2005

Instrumentalities for making music depend for their appeal mainly on the range of pitch, timbre, power, and complexity they provide. Musically the most desirable single instrument is one which gives the most versatile performance, without undue complication of playing technique.
A consideration ,of existing instruments leads to the conclusion that the application of modern electro-acoustic, instead of the old mechanico-acoustic operating principles, permits not only of a great extension of these musically desirable characteristics, but also a far greater flexibility in design, and a lowering of bulk, weight, and cost.
The many principles available for electro-acoustic design are discussed and lead to the struck string as the best compromise as a source of vibratory energy.
Methods for providing a wide range of tonal character and performance are described, and an instrument embodying these methods will be demonstrated, both for separate effects, and in a recital of musical compositions.
Normal Variations in Auditory Acuity
Authors: Josephson E. M. , Harelick Samuel 
Published: September 2005

Normal variations in auditory acuity are an important factor in all studies of sound and hearing. In the presence of a normal sound-conductive mechanism, these variations originate either in the cerebral processes involved in hearing, or in the end-organ of hearing, the cochlear mechanism.
Variations in auditory acuity of central origin, such as variations due to the state of attention of variations in the sleeping state, have not been thoroughly studied. They primarily involve the perception of sound. Disease of the perceptive mechanism of hearing, as in the presence of brain tumor or meningitis, gives rise to “central” deafness. Though little attention has been directed by modern otology to the differentiation of “central” deafness and deafness due to disease changes in the inner ear, there are a number of signs available for this differentiation.
Variations in auditory acuity of peripheral origin may be caused by many factors, such as barometric pressure, general bodily and circulatory tone and others; but the most interesting is the variation due to continued stimulation of the ear with sound. Whereas the mental processes involved in hearing perception show fatigue, as manifested by the determination by many observers of an increased differential of intensity, the end-organs of the normal ear do not fatigue on prolonged stimulation with moderate intensities of a frequency. On the contrary, prolonged stimulation of the ear with a moderate intensity of a frequency increases auditory acuity for that frequency, as is manifested by a drop in the threshold of intensity for that frequency by as much as 10 to 20 dbs.
These variations in auditory acuity are of high significance in the differentiation between deafness of peripheral and central deafness, which is thus for the first time made possible. For in the presence of peripheral deafness of the progressive type, the hearing shows marked fatigue on prolonged stimulation and a rise in threshold, as contrasted with the drop in threshold in the normal ear. In cases afflicted with central deafness there is found frequently a normal response of the ear to prolonged stimulation, pointing to normality of the ear and the end-organ and the central nervous nature of the disease process. The experience of one of us (Dr. Josephson) stresses the importance of this differentiation in cases of deafness; for he has found about 20 per cent of the cases referred to him with diagnosis by competent otologists of progressive deafness to be deafness symptomatic of tumor or disease of the brain.
Loudness and Pitch of Musical Tones and Their Relation to this Intensity and Frequency
Authors: Fletcher H. 
Published: September 2005

Loudness and pitch are psychological terms which are used to describe sensations produced when certain types of waves operate upon the hearing mechanism. Intensity and frequency are the corresponding terms to describe the physical quantities power transferred per unit area and vibrations per second executed by the sound wave. The relation between these psychological and physical aspects of a musical tone has been investigated using a group of typical listeners.
Precise scales were invented and used for representing the sensations of loudness and pitch. In comparing loudness a pure tone having a frequency of 1000 cycles per second and with intensity variable throughout the audible range is used as a reference tone. In comparing pitch, a pure tone having a constant loudness and with frequency variable throughout the audible range is used as a reference tone.
The intensity of a complex tone with ten components all equal in intensity but different in frequency is ten times that of each component, as is well known. On the other hand, the loudness of one such complex tone with frequencies which are harmonics of 500 cycles per second was found to be equal to that of the 1000 cycle component raised one thousand times rather than ten times in intensity.
An observer's location of the pitch was found to depend upon the intensity as well as the frequency. For example, the pitch of a 200 cycle tone was located at a position which was as much as one-quarter of an octave lower at the very high intensities than at the low intensities. For pure tones having frequencies near 2000 or 3000 cycles per second, no difference of pitch was observed as the intensity was changed.
Similar small pitch changes were observed with complex tones. Some very large changes were observed with particular changes in the components. For example, the pitch of a complex tone having four components of equal intensity, but with frequencies of 400, 600, 800, and 1000 cycles per second, was perceived as that corresponding to a 200 cycle tone. If to this complex tone, three additional components having frequencies of 500, 700 and 900 cycles per second, are added, then the pitch will be perceived as an octave lower or that corresponding to a 100 cycle tone.
An experimental demonstration will be given.
Extraneous Frequencies Generated in Air Carrying Intense Sound Waves
Authors: Thuras A. L. , Jenkins R. T. , O'Neil H. T. 
Published: September 2005

In high quality reproduction of sound the trend toward large power output necessitates a consideration of the more exact equations of wave propagation in air. If the displacement amplitude of a plane sound wave is not small the equation representing the propagation is not linear, and consequently harmonics and combination tones are generated. The pressure of these extraneous frequencies in terms of the fundamental pressure, frequency, and distance from the source has been mathematically determined by Earnshaw, Rayleigh and others. Rocard has recently applied the equation to exponential horns.
Measurements of the second harmonic and combination tones have been made at various points within a long tube, and in front of an exponential horn. Measurements, in general, agree with theory, but the absolute values are 3 to 4 db lower than the calculated values. An experimental demonstration will be given.
Echoes at Echo Bridge, Newton Upper Falls, Massachusetts
Authors: Jones Arthur Taber 
Published: September 2005

One span of this stone arch bridge crosses the Charles River. At the abutment on one side of the river a hand clap is returned as a series of echoes of decreasing intensity. Perhaps the sound waves are roughly focused by the arch, first on one side of the river and then on the other. At any rate, the echoes seem to be produced by reflection from the arch, not from some other object.
When the source is, as usual, on the bank it is to be expected that if an observer in a boat half-way across the river hears any echoes they will succeed each other twice as rapidly as when the observer is near the source. This is not the case. The observer in the boat does hear echoes, but they succeed each other at the same rate as when heard near the source. The explanation of this fact has not yet been found.
If both source and observer are near the middle of the river it is to be expected that the echoes will succeed each other considerably more frequently than when both are on the bank. On three different occasions this was found not to be the case. The echoes heard under these circumstances succeeded each other a trifle less frequently than when source and observer were on the bank. The reason seems to involve the fact that the boat is some distance above the center of the arch. The sound reflected from the arch is again reflected from the water before it comes to a focus, and this focus is near the vertex of the arch. From this point it spreads downward, is reflected by the water and again by the arch before the first echo is heard. On one occasion when the water was low the source and observer in the boat were nearer to the center of the arch, and the echoes came with a considerably greater frequency.
Measurement of Speed Fluctuations in Sound Recording and Reproducing Equipment
Authors: Kellogg Edward W. , Morgan Adolph R. 
Published: September 2005

High quality reproduction of recorded music is possible only if the speeds of recording and reproducing machines are maintained constant within very narrow limits. As improvements are made in these machines greater refinement in measurement of the variations is required in order that the progress may continue.
The development of an improved “Wow-meter” for such measurements is described, and various alternative schemes are discussed. The securing of a standard record, itself sufficiently free from imperfections, presents one of the most serious difficulties. For testing turntables a toothed steel wheel was built, in which special precautions were taken to minimize indexing and other possible errors. The current generated by means of this wheel is supplied to an electrical circuit so arranged that variations in frequency cause deflections of a galvanometer which are registered on a photographic film. The principle employed, namely, a resonant circuit slightly off tune, has been used in earlier devices. In the meter described, a push-pull arrangement has been adopted to reduce the likelihood of errors due to variations in voltage. A frequency meter of this type has certain inherent limitations in its ability to register very rapid fluctuations. Certain measures have been adopted to make the meter satisfactory in this respect, and the possibility of going further in this direction if necessary is given consideration.
Design Compromises for a Practical Sound Meter
Authors: Abbott Ernest J. 
Published: September 2005

Apparently there is no ideal sound meter, and any design represents a compromise between many factors such as cost, size, weight, sensitivity, range, reliability, and convenience and flexibility of operation, etc. While meters now on the market are reasonably satisfactory for noise surveys and sales demonstrations, few if any of them are suitable for practical machinery noise reduction work.
Some time ago the author was approached and asked to write a specification for a practical sound meter for general purpose noise work. This was an unusual opportunity to allow some one else to do all the development work on the well-nigh impossible meter which I had long hoped to build for my own use, and naturally I agreed. The present paper outlines the design compromises which were made, the reasons therefor, and the meter which was the result of the specification.
Observations Bearing on the Physiology of the Human Cochlea
Authors: Guild Stacy R. 
Published: September 2005

I have never held, and do not now have, any theory of hearing. There are as yet too many serious gaps in the factual knowledge of the ear to warrant theorizing. My part in this symposium will therefore be limited to the presentation of the observations made in our laboratory at Baltimore, and primarily to those made on the human ear by correlations of the records of hearing acuity with the histologic sections of the temporal bones. The observations that bear on the physiology of the cochlear part of the inner ear have already been published. (The principal paper with respect to high tones was published jointly with Drs. Crowe and Polvogt in the May, 1934, number of the Bulletin of the Johns Hopkins Hospital; and the data bearing on low tones were presented by me at a symposium of the American Otological Society last May and are published in the September, 1935, number of the Annals of Otology, Rhinology and Laryngology.)
Briefly, the evidence indicates localization for high tones (2048 cycles upward), but there is no evidence of localization in man for low tones (up to and including 1024 cycles). For the frequency of 8192 cycles the most important region of the organ of Corti is about 4 to 5 mm from the basal end of the cochlea; for 4096 cycles it is about 8 to 9 mm, and for 2048 cycles it is about 12 mm from the basal end. All tones up to and including 1024 cycles can be well heard when there is total atrophy of the organ of Corti in as much as the whole lower basal turn of the cochlea (this is about one-third of the entire length of the human cochlea). We have been unable to correlate the lesions found in the apical and middle turns with impaired hearing for low tones. No particular form of localization theory is favored by our evidence.
Physiological Acoustics; Pitch
Authors: Davis H. , Stevens S. S. , Lurie M. H. 
Published: September 2005

The electrical potentials generated in the cochleas of guinea pigs were picked up by electrodes in contact with the bone or external membranes of the cochlea and the neck muscles. These potentials were studied as a function of the position of the electrodes and the condition of the organ of Corti within the cochlea in order to determine the specificity of resonance of the basilar membrane to tones of various frequencies, and thereby discover the role of the cochlea in pitch perception.
Audiograms of the electrical response were taken before and after drilling through the cochlear wall and damaging the organ of Corti at various points. The exact location and extent of each lesion were determined by subsequent microscopic study of serial sections of the cochleas and these were correlated with the losses in hearing revealed by the audiograms. Good correlations were obtained in 20 animals between the boundaries of lesions and sharp departures of the audiograms from normal.
The positions of the resonant areas for tones of various frequencies indicated by these results are confirmed by the locations derived from an integration of the most recent data for differential sensitivity to pitch in human ears. High tones are localized near the basal end of the cochlea, 2000 c.p.s. is at the middle, and the lower octaves are closely bunched toward the helicotrema.
Change of Pitch with Loudness at Low Frequencies
Authors: Snow W. B. 
Published: September 2005

The changes in pitch which result from changes in the loudness of low frequency tones were investigated for several frequencies between 75 and 1000 c.p.s. with a crew of 9 observers. The loudness levels covered the range 20 to 120, and both telephone receivers and a loudspeaker were used as sound sources. Fletcher's pitch standard, a pure tone of loudness level 40, was employed.
All consistent judgments gave pitch shifts downward with increasing loudness, but large differences between individuals were found. Two observers perceived no shifts at any frequency or loudness while three others experienced changes greater than 35 percent at the highest intensity. Appreciable changes with time in individual judgments were found. There appeared insignificant difference between data obtained with telephone receivers or with the loudspeaker. A set of contours of equal loudness level, plotted on coordinates frequency and pitch change in percent, is given. These curves show a pitch change small at 1000 cycles, increasing to maximum at a low frequency and decreasing for still lower frequencies. The frequency of greatest shift increased from about 100 cycles at small loudness to about 200 at loudness level 120.
The Appendix describes automatic test equipment that greatly simplified the testing routine and improved its accuracy.
Application of Elastic Suspensions to High Speed Newspaper Presses
Authors: Livingston Stanley D. 
Published: September 2005

The effectiveness of various types of elastic suspensions when applied to complex mechanisms has been determined from an analysis of the test data which were obtained from several multi-unit newspaper press installations. Materials used as isolation mediums were natural cork, rubber pads and steel springs. The weight of the various installations ranged from four hundred and fifty tons to nine hundred and fifty tons. A semirigid assembly of press units now being erected will have a total sprung weight of approximately twelve hundred tons.
The vital question in the case of the original installation, which was made solely for the purpose of reducing the nuisance effect of the vibration transmitted to the building structure, pertained to the degree of elasticity permissible without materially affecting the production efficiency of the presses. It has been found that the transmission of vibration can be reduced to a minimum, and, if the suspension is properly applied, the production efficiency can be materially increased. Accordingly, some suspensions are now being installed solely for economical reasons.
The writer offers for discussion the subject of the transmission of vibration by means of “carrier frequency” and questions whether this phenomenon has been given the attention it merits.
Control of Temperature Variation in the Frequency of Tuning Forks (with demonstrations)
Authors: Eisenhour B. E. 
Published: September 2005

The increasing use of tuning forks not only as frequency standards but as controlling devices for equipment requiring perfect synchronization calls either for very accurate temperature control with the ordinary steel fork, or for the development of forks in which the variation of frequency with temperature is negligibly small.
Two methods have been employed to achieve this end—either the development of metal alloys having very small frequency-temperature coefficients, or the fabrication of compensated forks from two materials having coefficients of opposite sign. While alloy steels, such as Invar and Elinvar, can be produced having coefficients of the order of one-twentieth that of ordinary steel, yet very considerable variations in coefficients are found in individual samples of these alloys even when cut from the same piece of stock.
The combination of two alloys having positive and negative temperature coefficients has proven a more practical means of producing forks of uniform qualities and with frequencies independent of temperature. Demonstrations of the thermal properties of forks of this type will be made.
The Acoustical Planning of Broadcast Studios
Authors: McAllister G. Stanley 
Published: September 2005

Radio broadcasting is aware of the very close kinship of architectural acoustics.
The growth of radio broadcasting has not only been characterized by the substantial expansion and development of its scientific and technical aspects, but the industry has been aware of and is taking advantage of the newer knowledge of architectural acoustics. Many of the attempts to utilize the knowledge have been disappointing and others have been highly satisfactory.
As in all developments of a scientific or experimental nature, the lack of information on the subject or a mis-application of the principle may bring an unfortunate result, so in the application of acoustics to the design and construction of broadcast studios this same error may occur.
The broadcast engineer and the radio production man may not master the subject of acoustics, but he fully appreciates its value and need. His contribution to the knowledge of the problem may be somewhat small and may even be “unscientific,” yet that part may be the very element which the trained expert can utilize to the fullest extent.
The acoustical problem of the broadcasting studio is of a special nature requiring specific attention to the technique of design, shape, size, use, pick-up and flexibility.
Resonance in Certain Non-Uniform Tubes
Authors: Jones Arthur Taber 
Published: September 2005

When a solid rod is gradually lowered into an open organ pipe the pitch grows lower and then higher. The pipe and contained rod are equivalent to two tubes of different cross sections joined end to end. The equation for the frequency of such tubes is not new, but its consequences appear heretofore to have been examined only for cases where the narrow part of the tube is moderately short. The change in pitch may be surprisingly large, and agrees fairly well with that calculated.
Consideration is also given to a tube which consists of two cylinders joined by a flaring connector. For the one tube examined experimentally, the frequencies of the first five normal modes of vibration are found to be in satisfactory agreement with their theoretical values.
A General Theory of Passive Linear Electroacoustic Transducers and the Electroacoustic Reciprocity Theorem. I
Authors: Foldy Leslie L. , Primakoff Henry 
Published: September 2005

A theory of the operation of passive linear electroacoustic transducers is developed on the basis of the most general linear equations (in this case, integral equations) relating the pressure and normal velocity at each point on the transducer surface and the voltage and current at the transducer's electrical terminals. These, together with the appropriate solutions of the wave equation expressed through the use of Green's functions for the medium in which the transducer is immersed and the equations defining the electrical termination of the transducer, completely characterize the behavior of the transducer and allow explicit calculation of such quantities as impedances, responses, etc., in terms of four parameters entering the fundamental equations.
On the basis of this theory, a proof of the reciprocity theorem for electroacoustic transducers relating their speaker and microphone responses is presented embodying the conditions necessary for its validity. These conditions are essentially the existence of certain symmetry relationships among the transducer parameters. When these symmetry relationships may be expected to hold is to be discussed in Part II of this paper to appear later. Some applications of the theory are presented and others are outlined.