bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Sounds of Disease-Carrying Mosquitoes
Authors: Offenhauser Wm. H. , Kahn Morton C. 
Published: September 2005

Some 40 or more years ago, there was evidence of interest among scientists in the sounds of mosquitoes. Despite very crude acoustical apparatus, significant conclusions had been reached by the early investigators. Although very little was done in the next three decades despite the growth in the field of acoustics, interest has recently been renewed because of the world-wide need to check the spread of mosquito-borne tropical diseases. Recent experiments have confirmed many early findings and have provided valuable new data.
Mosquito sounds are distinctive; gross differences occur that are readily detected both by listening and by wave analysis. All fundamental sounds occur in the center of the sonic range (200–1000 e.p.s.); all are rich in harmonics. All sounds are warble-modulated, some at a single low rate in the order of 5 c.p.s., others at a double rate with the same lower rate and a higher rate in the order 5 times the lower. In some tones, some harmonics are completely interrupted while the fundamental remains undisturbed. Warble amplitudes are quite large; 20 percent is not unusual. The fundamental pitch often drifts; in one case, for example, there was a 25 percent increase in as little as 0.05 sec. Male sounds seem higher pitched than female; sound spectrograms show this to be due more to the difference in harmonic emphasis than to the difference in fundamental pitch. Generally speaking, mosquitoes do not generate or respond to sine-wave tones.
Mosquito sounds are low in energy level; the total sound power output of a female Anopheles albimanus whose sound was used to bait a mosquito-killing trap in Cuba was in the order of 10−13 watt. With this low power level it is difficult to obtain recordings with the high signal-to-noise ratios customary in high quality commercial recording because of the relatively high noise levels. Despite this handicap, it has been possible to reduce the noise due to microphonics, hum induction, vibration, and airborne and other disturbances to the point where recordings with 40-db signal-to-noise ratio are made frequently.
The Diffraction of Sound by Rigid Disks and Rigid Square Plates
Authors: Wiener Francis M. 
Published: September 2005

A rigid circular plate was exposed to an essentially plane progressive sound wave, and the sound pressure p at various points on the surface measured relative to the free-field pressure p0 in the undisturbed incident wave by means of a small probe microphone. The diffraction effect |p/p0| was determined as a function of angle of incidence over a range of frequencies beginning with “long” wave-lengths and extending into the region where the radius a of the obstacle approximately equals the wave-length. Expressed in customary notation, 14 &lt; ka &lt; 8, where k is the wave number of the incident wave. Data were obtained for angles of incidence θ = 0, 45, 135, and 180 degrees, where θ is measured with respect to the axis of the obstacle. Similar measurements for θ = 0 and 180° were made for a rigid square plate with side 2a.
Approximate contour maps of the quantity |p/p0| in decibels have been prepared from the experimental data portraying the pressure distribution on the surface of the plates.
The experimental results are compared with computed values of |p/p0| obtained from an approximate theory in which an attempt is made to solve the problem in terms of a scattered potential calculated as if the face of the obstacle were surrounded by an infinite baffle. The agreement is quite good on the “illuminated” side of the plates, i.e., for θ = 0 and 45° and on the “shadow” side for θ = 180°. The agreement for 135 degree incidence is generally poor, although the computed values show the trends of the experimental data in many instances. At low frequencies the theory gives values which are somewhat too high on the illuminated side and too low on the shaded side.
The values of |p/p0| obtained from the exact expression of the diffraction of a plane wave by a disk of zero thickness and for perpendicular incidence are found to be in good agreement with experiment and the approximate theory on the illuminated side (θ = 0) and they agree reasonably well on the shaded side (θ = 180°) for 1⩽ka⩽5. The region near the edge shows discrepancies which are to be expected from the finite thickness of the circular plate (approx. a/12).
It is concluded that the approximate theory mentioned above is capable of predicting the diffraction effect |p/p0| on the illuminated side of the obstacles in the frequency range covered by this study for the angles of incidence investigated. On the shadow side the theory can be expected to yield usably approximate answers only for θ = 180°. There are reasonable grounds for the assumption that similar predictions can be made for points on or “near” the surface of “thin” plane obstacles of arbitrary shape and for other acute angles of incidence not too close to θ = 90°.
A Study of the Mechanism of the Middle Ear
Authors: Onchi Yutaka 
Published: September 2005

I studied principally the mechanics of the middle ear, summarizing the anatomy and the physiology of the ear. I made Diagram I showing the anatomical structure of the ear, and translated it into physical terms of Diagram II, such as mass, spring, and frictional constant. etc. Thereafter I could get equations showing the mechanics of the middle ear through the Lagrangian equation. The complicated treatment for the kinetic, potential, and dissipation energies of the middle ear elements is for the purpose of expressing my opinion about the function of the middle ear which is partly different from the present contradictory medical views. By using the resultant equations of the motion of the ear and Diagram III (showing the electromechanical structure of the middle ear), I studied the mechanism of the middle ear under an assumption that the frequency characteristic curve of the inner ear is flat in a wide range. This assumption may be deduced from Luscher's experiment of the tympanic loading and hearing curves of men with complete defect of the tympanic membrane but with cochlear nerve intact. However, I do not explain it here, and it will be described in detail in further papers. From theoretical results thus obtained I made some experiments and calculation of the natural frequencies of the middle ear elements.
My conclusions are as follows: (a) The air vibration system of the ear which consists of the external auditory canal, the tympanic cavity, and the antrum can be shown electromechanically by Diagram III. (b) The middle ear has four main peaks of resonance on the hearing curves. (c) The middle ear and cochlea appear to be regarded as a displacement receiver and a pressure receiver, respectively. (d) The tympanic membrance has two important roles: (1) that of composing the vibration of the external auditory canala, of the antrum, and of the air cells of the mastoid process; and (2) that of propagating these vibrations to the ossicles. (e) The non-linear vibration of the tympanic membrane, the basilar membrane, and the secondary tympanic membrane, produce combination tones. (f) The air vibration system has an important role in understanding speech sounds. Its magnification of the sound intensity is above 50 db in a range from 700 or 800 cycles to 5000 cycles as in Fig. 5a. (g) This work offers a problem of design of a new audiometer, and is available for diagnosis of otological pathology.
Some Determinants of Interaural Phase Effects
Authors: Hirsh I. J. , Webster F. A. 
Published: September 2005

It has recently been shown that the binaural threshold for a pure tone presented against a background of noise depends upon the interaural phase differences of the tone and the noise. For example, the threshold of a low frequency tone, in phase at the two ears, is low when it is heard against noise that is out of phase at the two ears, but is high when it is heard against noise that is in phase.
The masked threshold of a 250-cycle tone presented against a background of intense noise is in fact about 15 db lower under antiphasic conditions than it is under homophasic conditions. (Homophasic refers to the condition in which the tone and the noise have the same interaural phase difference. Antiphasic refers to the condition in which either tone or noise, but not both, is out of phase at the two ears.) When the tone is masked by another tone, fairly close in frequency but not so close that beats are detected, the dependence of masking on interaural phase does not appear. The present experiment attempts to determine what characteristics masking sound (“masker”) must have if it is to produce interaural phase effects.
A 250-cycle tone was presented against four different kinds of background. The masking sounds were (1) pure tones, (2) regular pulses (125 p.p.s.), (3) random pulses (average 125 p.p.s.) and (4) random noise. Combinations of filters permitted the presentation of these maskers in frequency bands that were varied in width and center frequency.
The results indicate that the threshold for the tone in the presence of a regular, periodic masker does not depend to any significant degree upon interaural phase relations. A necessary characteristic of the masker that produces interaural phase effects is randomness or irregularity. Both masking and the interaural phase effects increase as the frequency band of a random masker approaches the frequency of the tone. Band width alone does not contribute to the interaural phase effects except as widening a band tends to bring one cut-off nearer the frequency of the tone. Wide and narrow band maskers, both of which contain the frequency of the tone, produce the same effects.
The Cathode-Ray Sound Spectroscope
Authors: Mathes R. C. , Norwine A. C. , Davis K. H. 
Published: September 2005

This device provides for rapid analysis of short samples of speech and other sounds. It permits direct viewing of the energy-frequency distribution of the sound at instants of time in a two-dimensional pattern, and also over intervals of time as a three-dimensional pattern. Magnetically recorded on a disk at slow speed, and speeded up 200 times on playback, the sample of sound is analyzed rapidly by a broad band high frequency system.
The three-dimensional portrayal (in time, frequency and amplitude) shows the whole sound sample, including an interval of about 12 sec., on one cathode-ray tube, together with a movable indication of the point in time at which the “instantaneous” or two-dimensional frequency-amplitude section, appearing on another tube, is taken. This two-dimensional pattern displays amplitude on a decibel scale and covers about a 40 db range. The complete pattern is made up of 190 amplitude values for the 100 to 4000 cycle frequency range so that the pattern is formed by 190 vertical lines. The effective band width of the resolving filter is 45 cycles. The patterns are scanned at a rate of 2/sec. so that a slow phosphor screen is used for viewing. Successive sections approximately 212, 5, 10, 20, or 40 milliseconds apart may be established and photographed automatically. Or for direct viewing manual selection of any desired point of analysis is provided.
Theoretical Aspects of the Reciprocity Calibration of Electromechanical Transducers
Authors: Thompson Sanford P. 
Published: September 2005

A unified theory of the reciprocity calibration of electromechanical transducers is presented in a form which facilitates the derivation of particular calibration theories. The theories of two types of calibration procedure are treated as special cases. One of the theories is shown to reduce, when lumped standards are used, to that of the original technique of Trent; the other is descriptive of a new procedure.
The application of calibration theories is discussed—particular attention being devoted to the use of distributed-constant standards and the consequent difficulties involved.
Musical Scales and Their Classification
Authors: Barbour J. Murray 
Published: September 2005

A musical scale is a sequence of musical intervals in a certain range, such as an octave; a mode is a cyclic permutation of a scale; a key is a mode at a certain pitch-level; a raga is a melodic pattern of a key. There are 66 heptatonic scales, 462 heptatonic modes, and 5544 heptatonic keys. For each key there are thousands of possible ragas, or a total of many millions of ragas.
Most writers, confusing scales and modes, have listed comparatively few of the possible scales. The older writers were further limited by harmonic considerations. Slonimsky's scales and melodic patterns (1947) are mostly ragas, in which, as with Schillinger (1946), symmetry is paramount; Slonimsky's pentatonic and heptatonic scales are actually modes.
The inverse of a scale contains the same intervals in reverse order. The complement of a scale contains all the notes of an octave not in the scale itself. A scale may be measured by the total mean-square deviation of all its intervals.
The notation of a heptatonic scale as a harp scale (with seven letter names) agrees with the deviation index. However, the function of notes in the scale may often be expressed by fewer than seven letter names or by two different names for the same note. For the composer, the intensive study of individual scales will be more rewarding than the listing of thousands of keys or millions of ragas.
A Concatenated Cone Speaker which Behaves Essentially as a Point Source
Authors: Bedford A. V. 
Published: September 2005

It is evident that if a speaker is to show great fidelity of reproduction of sound in all directions from the speaker, it must generate the same shaped waves for all frequencies. The generation of plane waves would require for the lower frequencies, a uniformly driven surface very much larger than is considered practicable for general use. (Dr. Hewlett's speaker is a good one of this type.)
The simplest means of generating a spherical wave apparently would be to use a piston whose diameter is smaller than the wave length of the highest frequency sound wave to be generated. However, a piston which is small enough to fill this requirement on 5000 cycles per second would have to move an absurdly great distance (several inches) at the lower audio frequencies to produce sufficient sound.
The present paper discusses and gives the results of tests on a new multiple cone structure speaker which changes its effective size so that it is practically a point source for all frequencies.
The transition from one effective size to another is made smoothly and in such a way that no major variations in response occur due to either interference or resonance.
Some New Instruments in the Iowa Laboratory for the Psychology of Music
Authors: Seashore C. E. 
Published: September 2005

This is a report describing briefly the following new instruments developed by the staff in the University of Iowa.
1. Piano camera: a camera which records the time and the force of the stroke for the entire keyboard in piano playing, under normal conditions of playing. (Tiffin and Seashore.)
2. Certain modifications of Metfessel's strobophotographic camera which graphs pitch and time of a solo instrument or voice, photographically. (Reger and Tiffin.)
3. The new synthetic vibrato apparatus: utilizes the photoelectric cell in controlling all the factors in the vibrato. (Tiffin.)
4. The rhythm meter: a graphic method of measuring precision in rhythm performance. (Seashore, C. E. and R. H.)
5. The tone dynometer: a means of measuring precision in musical “touch.” (Seashore.).
6. A new model of the tonoscope: portable and adaptable for general laboratory and studio use. (Seashore and Williams.)
The Reverberation Time Bridge—An Instrumental Method for Measuring Reverberation Time
Authors: Olson Harry F. , Kreuzer Barton 
Published: September 2005

The analogy between the decay of the electrical energy in a capacitor shunted by a resistor and the decay of sound energy in a room with sound absorbing walls is the basis of this bridge.
The sound pressure is converted into a corresponding electrical voltage by a microphone and amplifier. This voltage is measured by a linear type v.t. voltmeter. The voltage across the resistor shunting the capacitor is measured by another similar v.t. voltmeter.
The room and capacitor are “charged” until steady state conditions are established, the capacitor charging voltage and the sound source are then cut off simultaneously. The bridge is balanced by adjustment of the variable discharge resistor, until the two voltages are equal during the decay period.
The value of “t” in the “time constant” of the electrical circuit is then the actual reverberaone time.
Incommensurability of the Octave Interval with any other Interval
Authors: Bartholomew Wilmer T. 
Published: September 2005

Although it is common knowledge that the well-known tempered scale of twelve semitones is imperfect, relatively few musicians understand the necessary cause of that imperfection, which lies in the mathematical relations of the ratios involved.
In any method of tuning, the ear demands that at least the octaves must be true. It is demonstrated that if this is so, no other true interval, if successively stepped off from a starting tone, can ever arrive at an exact octave of the starting tone.
The mathematics, though elementary and obvious to the scientific musician, is important since it underlies all attempts at tempering scales.
I. Theory of the Electrostatic Loud Speaker
Authors: Hanna C. R. 
Published: September 2005

In the electromagnetic driver the force per unit current has been shown to be a function of the inductance and the negative stiffness resulting from the presence of the steady magnetic field. In this paper it is proven that the force per unit voltage in the electrostatic device is a similar function of the capacity and the negative stiffness due to the steady electrostatic field.
A new concept called Motional Admittance is introduced for the electrostatic loud speaker and this is shown to be similar in its mathematical form to the Motional Impedance of the electromagnetic driver.
A calculation of the ultimate theoretical efficiency that may be obtained with an electrostatic speaker having a pure resistance radiator and covering a given frequency range is given. It appears that efficiencies between 5 and 10% may some day be obtainable with good fidelity of reproduction.
Loud Speaker Sound Pressure Measurements
Authors: Kellogg Edward W. 
Published: September 2005

Methods of taking frequency-response curves of loud speakers have tended to become prematurely standardized within commercial organizations, and inadequately standardized in the industry as a whole. Characteristics taken by different experimenters are not comparable. Each may have a good defense to make of his system, and it is the writer's plea that such discussion should be “A free for all, and not a private affair.” More general discussion would promote education if not standardization. A critical attitude on the part of all is desirable, and a demand that published curves be accompanied by information as to method of test.
Two valuable contributions on the subject have so far been published, in which the result obtained by several methods of test are compared. This paper makes additional contribution to the experimental evidence, suggests some other methods of measurement, and criticises the several methods from a theoretical standpoint. One of the difficulties arises from the fact that it is desired to show a single curve whose flatness is an indication of the general merit or fidelity of the loud speaker, whereas the differences in directive properties as well as in total sound output make it impossible to describe the properties of a speaker in a single curve. Only in as far as it is possible to specify the exact conditions under which the loud speaker will be used, can such a single curve have significance.
Masking Effects of an Interfering Tone Upon a Deafened Ear
Authors: Guttman John , Ham L. B. 
Published: September 2005

These experiments were made to test the masking function of deafened ears by means of two tones. The threshold intensity of the person examined is obtained for the one tone and then this intensity is increased 50 decibels. This tone we have called the interfering tone. The threshold intensity of the other tone (i.e., the primary) is found with and without the interfering tone. The difference between the two threshold intensity values of the primary tone is called the differential threshold.
We have found the differential threshold to be smaller for deafened people than for normal people. The greater the deafness in the primary tone, the smaller the differential threshold. These findings were found for both the so-called conduction as well as perception deafness. In conduction deafness the effect may be a little more pronounced.
An analysis of the results, especially for the more deafened cases, indicates a supplementary explanation to Paracusis phenomena.
An explanation of the results is given, based upon the supposition of a very sensitive mechanism for damping the transmission of strong sounds. This mechanism acts by reflex action of the cochlea nerve and the nerves supplying the intra-auricular muscles.
Acoustics of Lincoln Hall Theater at the University of Illinois
Authors: Watson F. R. 
Published: September 2005

Recent theory indicates that perfect acoustics in an auditorium may be obtained by observing conditions leading first, to the perfect generation of sound, and second to the perfect reception of sound. In the generation of sound, it is of great advantage to place reflecting surfaces near the performer to allow him to “hear himself” and thus adjust his sound for best effect. For perfect listening, it appears desirable to reduce as far as possible all reflection of sound about the auditors, since practically all the defects of echoes, reverberation and articulations may be traced to this reflection.
Opportunity to test this theory was given in the construction of a small theater at the University. A huge cyclorama on the stage gave the reflecting surface for performers, while upholstered seats and a very absorbent ceiling treatment reduced reflection for auditors. The acoustic outcome is good.
Movies of Vocal Cord Speech and Voice Quality Vocal Cord Function
Authors: Russell G. Oscar 
Published: September 2005

These are the first moving picture experiments to be obtained, bearing on the fundamental problems involved in a consideration of speech and voice quality vocal cord function.
Most of our theories of speech have heretofore assumed a harmonic complexity of tones produced by the actuator or vocal cords. The moving picture photographs of the heretofore inaccessible interior larynx interior and lower throat now show for the first time that this is an impossible postulate.
Speech and voice quality differences have heretofore been ascribed to a function of the total air volume cavity capacities above the vocal cords—in other words to a cavity tone modificatory influence. These pictures likewise prove that these theories are untenable and that a large part of the voice quality and many vowel quality differences may be traced to a function of the interior larynx.
THEORY OF THE ELECTROSTATIC LOUD SPEAKER
Authors: Hanna C. R. 
Published: September 2005

In the electromagnetic driver the force per unit current has been shown to be a function of the inductance and the negative stiffness resulting from the presence of the steady magntic field. In this paper it is proven that the force per unit voltage in the electrostatic device is a similar function of the capacity and the negative stiffness due to the steady electrostatic field.
A new concept called Motional Admittance is introduced for the electrostatic loud speaker and this is shown to be similar in its mathematical form to the Motional Impedance of the electromagnetic driver.
A calculation of the ultimate theoretical efficiency that may be obtained with an electrostatic speaker having a pure resistance radiator and covering a given frequency range is given. It appears that efficiencies between 5 and 10% may some day be obtainable with good fidelity of reproduction.