bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confidence Ratings, Second-Choice Responses, and Confusion Matrices in Intelligibility Tests
Authors: Clarke Frank R. 
Published: September 2005

The studies reported in this paper have dealt with the responses of human observers to speech stimuli transmitted in a background of white Gaussian noise. In all cases the listeners attempted to identify the transmitted items and then made a second response in an attempt to convey additional information. It was found that when the listeners were allowed a second-choice identification response, very little information was contained in these responses which was not already contained in the listeners' first identification response. When the second response was a confidence rating, significant amount of information was added to that which was carried by the identification response.
The rating which followed each identification response was assigned by the observers in an attempt to estimate the probability that their identification response was, in fact, correct. For message sets of four items and for sets of sixteen items, it was found that the observers were quite capable of making such estimates over a wide range of speech-to-noise ratios. Their estimates did appear to be affected to some extent by the size of the message set and by the speech-to noise ratio, but this interaction was slight.
The observers' rating responses were used to generate ROC curves. These curves were adequately fit by straight lines when the data were plotted on normal-normal probability paper. Regardless of the size of the message set, all curves, for all speech-to-noise ratios, were fit by a single slope. However, the point at which these curves intersected the abscissa was a function of both variables.
Data from one set of observers in the rating experiments were used in an attempt to predict the performance of a different group of observers whose task was to monitor subsets of messages. While predictions were fairly good, discrepancies were noted. An internal check in the monitoring experiment strongly suggests that these discrepancies arose because of differences between the two groups of observers.
On the Stability of a Plane Flame Front in Oscillating Flow
Authors: Markstein G. H. , Squire W. 
Published: September 2005

Recent experimental studies revealed a close connection between spontaneous excitation of organ-pipe oscillations by flames propagating in tubes and flame front instability characterized by cellular structure. On the basis of these observations a dominant mechanism of vibratory flame movement is proposed, consisting of the following two steps:
1. As a consequence of acceleration instability, the oscillation of the gas column alternatingly distorts and flattens the flame front, thus creating the observed vibration-induced cell structure.
2. The distortions of the flame front cause in turn periodic changes of flame surface area and therefore of burning rate. Spontaneous oscillations are excited if the phase relation between burning rate variation and pressure oscillation is favorable.
In this paper only the first step is analyzed. The linearized treatment yields stability limits in terms of dimensionless parameters representing amplitude and frequency of gas column oscillation and wavelength of flame front distortion. The properties of the flame front entering into the analysis are the ratio of densities of unburned and burned gases, the burning velocity of the plane flame front, and a characteristic length that determines its stability in the absence of oscillations. Results in qualitative agreement with experimental observations are derived.
Measurement of Difference in Loudness Between Typing Noises
Authors: Abruzzo Joseph 
Published: September 2005

It is difficult to ascertain the absolute loudness of typing noise by objective measurement. However, it may be practical to use such measurement to determine the loudness level difference in a comparison of the sounds from two typewriters. The requirements that must be met by an accurate measurement technique depend on the degree of accuracy required. Information pertaining to the accuracy necessary has been obtained by employment of two loudness matching procedures over a period of several months. The purpose of the tests was to determine the difference in sound-pressure level of typing noise necessary to enable a person to identify reliably the louder of two typewriters operated simultaneously in a quiet background. It was found that under the conditions adopted for the investigation, differences in sound-pressure level had to be nearly one decibel before they could be recognized 50 percent of the time.
Characteristics of typing noise other than pressure level are discussed. The opinion is expressed that these will, in many cases, not cause significant measurement error, and that difference in loudness between typing noises can often be measured with practical accuracy by means of a sound-level meter.
The Fusion of Intermittent White Noise
Authors: Symmes David , Chapman Loring F. , Halstead Ward C. 
Published: September 2005

Stimulus variables influencing the fusion of interrupted white noise have been re-examined in a single trained observer using repetition rate as the independent variable. Critical auditory decay times have been calculated for all observed fusion thresholds under the assumption that the cue for the perception of minimal flutter is a decay of one detectable step in the loudness of the interrupted signal during the off interval. These critical decay times are satisfactorily described by the value 120 milliseconds (independent of intensity) when the burst duration in the interrupted signal is longer than a critical value (5 milliseconds for this listener), but for shorter burst durations the decay times are much lower and exhibit a relationship to burst duration and intensity. A shift in the population of neural units activated under the latter conditions is postulated as an explanation.
The range of individual differences in flutter fusion thresholds under standard conditions has been examined by the use of a tape recorded test requiring repeated discriminations of interrupted from continuous noise. From a sample of 46 normal individuals a population of threshold scores may be postulated having a mean critical fusion frequency of 82.1 interruptions per second with a standard deviation of 19.4 when the interrupted noise has a sound-time fraction of 0.90 and an intensity of 70 db re 0.0002 dyne/cm2.
Sound Field of a Rectangular Piston
Authors: Freedman A. 
Published: September 2005

The amplitude and phase of the pressure in the field of a rectangular piston, assumed vibrating within an infinite, rigid baffle, are examined theoretically for ranges down to the order of the piston length. Various laws of behavior of this field, both on and away from the acoustic axis, are deduced. An indication is given of the errors introduced by the approximations used. Such experimental evidence as is available supports the theory.
Simple means are provided for constructing curves of axial pressure amplitude and phase for any ratio of length to breadth of the radiating surface, and a method is suggested for predicting the long-range axial pressure of a rectangular piston from measurements taken well within the latter's Fresnel region.
The near fields of a rectangular and a circular piston are compared. That of the rectangular piston produces the more useful approximation to a plane wave.
Acoustic Loci and Transitional Cues for Consonants
Authors: Delattre Pierre C. , Liberman Alvin M. , Cooper Franklin S. 
Published: September 2005

Previous studies with synthetic speech have shown that second-formant transitions are cues for the perception of the stop and nasal consonants. The results of those experiments can be simplified if it is assumed that each consonant has a characteristic and fixed frequency position, or locus, for the second formant, corresponding to the relatively fixed place of production of the consonant. On that basis, the transitions may be regarded as “movements” from the locus to the steady state of the vowel.
The experiments reported in this paper provide additional evidence concerning the existence and positions of these second-formant loci for the voiced stops, b, d, and g. There appears to be a locus for d at 1800 cps and for b at 720 cps. A locus for g can be demonstrated only when the adjoining vowel has its second formant above about 1200 cps; below that level no g locus was found.
The results of these experiments indicate that, for the voiced stops, the transition cannot begin at the locus and go from there to the steady-state level of the vowel. Rather, if we are to hear the appropriate consonant, the first part of the transition must be silent. The voiced stops are best synthesized by making the duration of the silent interval equal to the duration of the transition itself.
An experiment on the first formant revealed that its locus is the same for b, d, and g.
Sound Energy Integrator with an Electrostatic Squaring Device
Authors: Lochner J. P. A. , Meffert P. 
Published: September 2005

Investigations of the contribution of short-time delayed echoes to the intelligibility of speech have brought out the fact that reflections arriving within 95 msec after the direct sound in an auditorium have a positive contribution, and, reflections after this period, a negative contribution to the intelligibility of speech.
The instrument described, developed for the analysis of reflection patterns in auditoria, incorporates an electrostatic squaring device and an electronic counter as registration unit. Sound energy can be integrated by means of this instrument over pre determined short periods at any given interval after the direct sound.
Auditory Testing of a Simplified Description of Vowel Articulation
Authors: House A. S. , Stevens K. N. 
Published: September 2005

An auditory test to establish the adequacy of an idealized specification of vowel articulation is described. Articulatory configurations of the vocal tract are specified by means of three numbers: the position of the point of greatest constriction, the degree of constriction at that point, and the size of the mouth opening. The stimuli in the recorded test are the outputs of 279 such configurations of an electrical vocal-tract analog. All sound samples are highly similar in duration, intensity, start-stop characteristics, and fundamental frequency and inflection. The instructions to subjects are standardized, and are of two types: one restricts responses to one of nine vowel categories while the other permits a nonvowel response as well. Subjects were experienced in phonetic transcription.
The ranges of articulatory configurations identified as given vowels by the subjects are plotted as contours, and these data are compared to results of other investigators. Certain disagreements are pointed out and discussed. The results, in general, show good agreement with previous data, and demonstrate, therefore, the adequacy of the three-number articulatory description.
Ultrasonic Shutter
Authors: Darner Charles L. , Bobber Robert J. 
Published: September 2005

The ultrasonic shutter is a thickness-expander plate of barium titanate which, when placed in a beam of ultra-sound, will control the transmission of sound through it over a 40 db range near the frequency of half-wave resonance. Control is exerted by means of a passive electrical network connected directly to the plate electrodes.
Theory of the “shutter effect” and supporting experimental data are presented.
Stereophonic and Quasi-Stereophonic Reproduction
Authors: Lochner J. P. A. , de V. Keet W. 
Published: September 2005

In stereophonic reproduction there are two distinct qualities which distinguish it from single-channel reproduction. The first of these is a directional separation of sound sources and the second, and probably the most important characteristic of stereophonic reproduction, is the sensation of “depth” and “presence” that it creates.
It is well known that the relative amplitudes and times of arrival at an observer's ears of first sounds received from the loudspeakers determine the apparent direction of the sound sources in a stereophonic system, and it is often assumed that this is also responsible for the perception of “depth” and “presence” normally linked with this system. It appears, however, that only the former quality, directional separation, is based on the relative amplitudes and times of arrival of first sounds and that the latter quality, which we call “ambience,” is entirely on account of delayed reflections or echoes recorded and reproduced through the separate channels of the stereophonic system.
Single recording-channel quasi-stereophonic systems, in which these echoes were brought out as in the stereophonic system, but which could not give separation of sources, were subjectively compared with true stereophonic systems and the results are presented in this paper.
New Method of Recording the Sound Transmission Loss of Walls as a Continuous Function of Frequency
Authors: Waterhouse Richard V. , Cook Richard K. 
Published: September 2005

An apparatus has been developed which records as a continuous function of frequency the difference in decibels between the sound levels in two rooms separated by the partition under test. The quantity recorded differs from the transmission loss only by a small correction for the Quiet-room absorption and partition area. Experimental results are presented.
An electronic potentiometer recorder is used as a self-balancing device. The voltages produced by microphones in the Loud and Quiet rooms are applied to the recorder, which drives a logarithmic attenuator and continuously reduces the Loud voltage to the same value as the Quiet voltage. The voltages are balanced at an attenuator setting which is determined by the sound transmission loss and this is plotted linearly in db on an 11 inch scale, which may be chosen as 0–60 db or less.
Dimensional Analysis of Cochlear Models
Authors: Tonndorf Juergen 
Published: September 2005

It is generally known that events occurring in different systems which, although differing in size, are physically similar can be quantitatively related to each other by Dimensional Analysis. The significance for Auditory Theory of various phenomena observed previously in cochlear models would be considerably increased if a dimensional analysis were performed of these models.
This paper represents an attempt at such an analysis. In the amplitude domain, its results suggest a close relation between the levels at which Bekesy's eddies first become visible in the model and at which harmonic distortion first becomes audible in the human ear. In a previous paper on cochlear models, evidence had been given that the appearance of Bekesy's eddies represents the onset of harmonic distortion in the model. The present analysis has strengthened the validity of this concept.
Calibration for Carrier Operated Microphones and Other Reversible Transducers
Authors: Burkhard M. D. , Corliss E. L. R. , Koidan W. , Biagi F. 
Published: September 2005

An insert technique described in this paper makes it possible to carry out sound pressure measurements using a microphone operated in a carrier circuit with almost the same accuracy as can be achieved with more conventional preamplifiers. The carrier system is modified to include a microphone polarizing voltage if the transducer is not self-polarized. Then a calibrating audio-frequency voltage is used to drive the transducer diaphragm to the same displacement amplitude as that generated by the sound pressure. Instead of matching the open-circuit voltage of the microphone, diaphragm motion is matched. A displacement response constant, independent of frequency, is used to determine sound pressure, in contrast to the usual open-circuit response, which depends on frequency.
In a manner analogous to the determination of open-circuit pressure response by the reciprocity technique, the acoustic admittance of the microphone may be evaluated from a series of three voltage ratio measurements and the calculated acoustical transfer admittance of a calibrating coupler. This result can be combined with the open-circuit pressure response determined by the reciprocity technique to give an explicit evaluation of the electromechanical coupling constant.
Propagation of Sound in Thin Elastic Shells
Authors: Young James E. 
Published: September 2005

A wave theoretical analysis of symmetric mode propagation in a medium confined by a cylindrical elastic shell is carried out. An expression is obtained for the axial propagation constant, specialized to that case of a thin steel shell surrounding a column of air. This is further restricted to the description of the lowest symmetric mode.
The dispersion predicted by the analysis is in order of magnitude agreement with that obtained on a transmission line picture.
Fixed Path, Variable Frequency Acoustic Interferometer
Authors: Leon Herman I. 
Published: September 2005

A fixed path, variable frequency acoustic interferometer is described that is particularly suited for measuring ultrasonic velocities in liquids as a continuous function of temperature and pressure of the medium. The interferometer contains two clamped crystals: one, a low intensity ultrasonic source; and the other, a fixed, parallel reflector. The frequency of excitation, supplied from a frequency generator, is varied, and cyclic changes in input impedance are detected in an impedance bridge circuit. Crystal resonance is avoided. The interferometer, addition to the usual advantages of a fixed path system over a variable path one, operates at very low power levels; hence, it avoids problems occasioned by high intensity pressure waves. Frequency, the measured variable, is one that can be precisely measured with comparative ease.
The complete equivalent network for either the fixed or variable path interferometer is presented, from which the operation of the fixed path, variable frequency system is derived. The effect of crystal backing impedance is discussed, and the characteristics of the interferometer are shown to be those of a double crystal interferometer having infinite backing impedance.
The velocity of sound in water is measured between 25 and 53°C in the frequency range of 600 to 800 kc. At 25.0°C the measured velocity is 1496.8±0.3 meters/second, and the temperature coefficient is +2.7 meters/second °C.
Mechanical Impedance of the Forehead and Mastoid
Authors: Corliss Edith L. R. , Koidan Walter 
Published: September 2005

A method has been developed for determining the resistive and reactive components of the impedance of the human head and mastoid, or of other high mechanical impedances, using a special direct-recording measuring system that records both force and motion. Impedances presented to driving tips of 12.5 and 20 mm diameter have been measured over the audio-frequency range from 40 to 10 000 cps. The effects of static force coupling the head to the driver have been compared for 500- and 1000-g coupling forces. Over a large part of the audio-frequency range, the predominant characteristic of both head and mastoid impedance is a stiffness reactance, with some damping. In the high-frequency range, a small mass reactance parameter appears. The mass load due to the whole head influences the impedance only at the low-frequency extreme of the measurement range.
The driving system consisted of a tubular section of polarized barium titanate, rigidly clamped at one end to a massive wall. Force and motion were measured close to the point of contact with the lead, to minimize errors arising from flexure in the driver or between the sensing elements. The system was calibrated by loading the driving tip with known masses.
Auditory-Threshold Recovery after Exposures to Pure Tones
Authors: Hirsh I. J. , Bilger R. C. 
Published: September 2005

A modified Békésy-type audiometer was used to obtain a continuous recording of the auditory threshold before and after monaural exposures to different durations and intensities of pure tones. Preliminary studies confirmed the observations of Reger that the amount of temporary hearing loss at 1 kc following a 1-min exposure to a 1-kc tone is greater when the stimulating tone is 20 db above threshold than when it is 80 db above threshold. Temporary hearing loss at higher frequencies, however, increases with exposure level. These preliminary results led to an investigation of the dependence of temporary hearing loss on the duration and the intensity of exposure tones.
Recovery curves for the threshold at 1 kc following exposure by 1 kc indicate that exposure tones at or above 60 db sensation level yield a rapid recovery followed by either a slowing down of the recovery process or a second rise in the threshold. Following exposure to a 20-db tone, however, this rapid recovery is not so apparent, and therefore, when the temporary threshold shift is measured soon after exposure, the apparent loss after 20 db is greater than after higher intensities. The hearing loss two minutes after exposure does not change with increasing exposure level until the sensation level exceeds 80 db. Also, temporary hearing loss does not change significantly with exposure durations from 15 sec to 1 min but increases as the durations increase to 2 and 4 min.
These findings do not hold when the threshold for 1400 cps is measured following exposure to 1 kc. Here, temporary hearing loss increases directly with duration for sensation levels at 80 db or above, and it increases directly with level for sensation levels greater than 60 db. Although these results are somewhat obscured by differences among individuals, the recovery curves, and their dependence on intensity and duration of exposure, point to more than one underlying recovery process.
Simultaneous and Alternate Listening and Speaking
Authors: Poulton E. C. 
Published: September 2005

Listening and speaking simultaneously was compared with listening and speaking alternately. The presented message was masked by the subject's voice to approximately the same extent in the two cases. Results: the simultaneous condition gave more errors than the alternate condition.
In learning to repeat back what they heard in the simultaneous condition, all subjects initially tried to repeat what they heard as they heard it. They thus made meaningless sounds, without being aware that they were doing so.
Radial Vibrations in Short, Hollow Cylinders of Barium Titanate
Authors: Stephenson C. V. 
Published: September 2005

The theory of radial vibrations in short, hollow cylinders of barium titanate has been developed. This development results in an expression which relates the radial coupling coefficient to the measurement of the resonant and antiresonant frequencies of the first harmonic of the radial mode of vibration. The important parameter in this development was found to be the ratio of outside diameter to inside diameter, and once this ratio was given, the expression relating coupling coefficient to resonance measurement took a particularly simple form. An interesting result of theory was that for any value of the ratio of diameters, many of the higher harmonics are forbidden in this mode of vibration.
Experiments were devised to test some of the theoretical conclusions and were found to be in excellent agreement with the theory.
Sound Propagation in a Fluid-Filled Tube with Massive Wall Reactance
Authors: Junger Miguel C. 
Published: September 2005

The results of an experimental study of a relatively unfamiliar mode of propagation are presented: the zero-order mode in a tube with massive wall reactance. The observed and theoretical disperison curves, which show good agreement, display a high-pass cut-off frequency. There is a dead zone between this frequency and the ring resonant frequency of the tube.
The phase velocities c2 are measured indirectly from the directivity patterns of a receiver in the form of a long rubber hose coupled to a microphone; these patterns are characterized by two symmetrical lobes whose angular separation is 2 cos−1c/c2, c being the sound velocity.