Volume 64, Issue S1, November 1978
Index of content:
- PROGRAM OF THE ACOUSTICAL SOCIETY OF AMERICA AND THE ACOUSTICAL SOCIETY OF JAPAN JOINT MEETING
- Session A. Comparative Studies of Hearing in Vertebrates: Workshop I Hearing in Fishes and Amphibians
- Invited Papers
64(1978); http://dx.doi.org/10.1121/1.2004089View Description Hide Description
Morphological, behavior, and physiological data indicate that there is considerable interspecific variation in auditory function among the more than 20 000 teleost species. This variation includes mechanisms for sound reception, pathways of sound conduction to the ear, excitation patterns within the ear, and possibly, the mechanisms for information processing by the auditory nerve and central nervous system. Although it is still difficult to understand hearing function in terms of our present conceptions of the underlying physiology and structure, it is becoming clear from limited behavioral and physiological data that the auditory systems in at least several teleost species are well adapted for temporal analysis of acoustic signals. This suggestion is in accordance with recent observations that the temporal rather than the spectral patterns of teleost sounds are significant for communication. [Work supported by grants from NIH and NSF to ANP and NSF to RRF.]
64(1978); http://dx.doi.org/10.1121/1.2004090View Description Hide Description
Several fish with swimbladders have been shown to detect the angular location of a source of low‐frequency pure tones, e.g., 75 Hz, if it is situated in the “horizontal” plane of the fish. Moreover cod possess truly three‐dimensional directional hearing. Two variables are pertinent: particle acceleration a(t) and acoustic pressure p(t) at the position of the fish. Directional information in a(t) might be obtained through differently oriented acceleration detectors such as the otolith organs. Electrophysiological evidence supports this. Time of arrival differences appear irrelevant. Bony fish with swimbladders (cod, ide) show a 180° reversal in directional response if a sinusoidal sound field with a(t), p(t) is replaced by a(t), −p(t). This suggests a phase analysis to overcome the 180° directional ambiguity when inferring propagation direction from a(t). Pressure is transformed by the swimbladder into accelerations along a line of action characteristic for the recording site in the labyrinths. Sharks, which lack swimbladders, show acoustic attraction from afar. It is unknown how they are able to localize the source if the detection is also based on a phase comparison system.
64(1978); http://dx.doi.org/10.1121/1.2004141View Description Hide Description
Morphological variation in the primary projections of the inner ear and acousticolateralis variation in agnathans, chondrichthians, bony fishes, and amphibians is reviewed and used to examine several hypotheses concerning auditory evolution in anamniotes. The acousticolateralis hypothesis regarding the origin of the inner ear is rejected on the basis that all vertebrates, including the earliest fossil agnathans, possess both lateralis and labyrinth systems. Embryonic evidence regarding development of the labyrinth, lateralis, and other special sense organs suggests they are serial homologues sharing a common neural crest‐placodal origin, and that all special senses are equally old phylogenetically. The labyrinth hypothesis of the origin of audition can not be rejected or accepted, as there is insufficient evidence regarding the phylogenetic distribution of audition in anamniotes. The hypothesis that audition arose by the invasion and replacement of lateralis fibers by acoustic afferents in the acousticolateralis medullar centers is rejected, based on new experimental evidence that these systems in fishes maintain primarily separate central pathways. Finally, the acousticolateralis area of Latimeria is discussed and compared with that of amphibians.
64(1978); http://dx.doi.org/10.1121/1.2004142View Description Hide Description
The amphibian auditory periphery is traditionally viewed from one of two perspectives: (1) that it is degenerate and by implication derived from the amniote condition or (2) that it represents, at least in most frogs, a simple intermediate condition between the ears of rhipidistian fishes and reptiles. These two perspectives, or various hybrids, guide modern workers in the design of their investigations and the interpretation of the data resulting from these studies. The development and diversity of the amphibian auditory periphery is reviewed and compared to that of amniotes. The otic region in key fossil tetrapods is reviewed. Our current concepts of otic homology are reviewed and some alternative homologies are suggested. This review indicates that the most parsimonius perspective on the amphibian auditory periphery is that it represents a unique experiment in aerial hearing unrelated to that found in modern amniotes. The implications of this perspective for modern morphological and experimental work are discussed. [Work supported by NSF.]
64(1978); http://dx.doi.org/10.1121/1.2004143View Description Hide Description
Behavioral field studies involving playback of natural and synthetic calls indicate that anurans (frogs and toads) respond selectively to the calls of their own species. Furthermore they can localize a sound source with remarkable accuracy (despite the relatively small interaural distance between their eardrums). Electrophysiological studies reveal that their peripheral auditory system is tuned to the spectral and temporal features in their species‐specific calls, and that their ear is directionally sensitive. Recordings from central auditory nuclei verify a hierarchical organization in encoding complex sounds of biological significance as well as the existence of binauralinteraction subserving sound localization. These studies of anurans serve as a model for neural processing in the auditory systems of higher vertebrates. [Supported by NIH Grant NS‐09244.]
- Session B. Comparative Studies of Hearing in Vertebrates: Workshop II. Hearing in Reptiles and Birds
64(1978); http://dx.doi.org/10.1121/1.2004192View Description Hide Description
Hearing in reptiles is of particular interest because of the diversity in the anatomy of the reptilian auditory system. This diversity is best illustrated in the lizard, where there is significant variation in cochlear anatomy across families. This review of the auditory physiology of reptiles will begin with a detailed discussion of the extensive physiological data available for the alligator lizard (Anguid family). These data include measurements of basilar membrane motion, intracellular hair cell responses, and single‐unit activity of primary auditory‐nerve fibers. Single‐unit data from an Iguanid lizard will be compared to that for the alligator lizard and discussed in terms of the differences in cochlear anatomy of these two families. In addition, single‐unit data for other lizards and other reptiles will be reviewed. The presentation will conclude with a comparison of auditory processing in the reptile and the mammal and will consider issues such as the tuning of individual fibers and the relationship of anatomical structure to physiological response.
64(1978); http://dx.doi.org/10.1121/1.2004193View Description Hide Description
The structures of the avian outer and middle ears are furnished by the most extensive adaptive variations according to different ecological requirements. The cochlea with lagena is almost straight and cell arrangement in the cochlear duct is distinguished from the mammalian: Two types of hair cells lie in one continuous row, the cilia are inserted firmly into the tectorial membrane, the pattern of nerve innervation is quite different from that of the mammalian corti, and the orderly seqence of innervation on the basilar membrane is reserved obviously in tonotopical organization of the cochlear nuclei. Songbirds can hear most of the frequencies in their vocalization, while their ears are not the kind of specialization for communication seen in orthopterans and frogs: Recognition of conspecific songs involves in processing in the higher CNS rather than in the range of frequency alone. The behavioral relation of vocalization and hearing may light on tentative approaching the problem of pattern recognition in auditory CNS.
64(1978); http://dx.doi.org/10.1121/1.2004237View Description Hide Description
Psychophysical investigations of hearing in a number of avian species over the last decade have added significantly to our knowledge of hearing capabilities characteristic of this vertebrate group. Behavioral measures of absolute auditory sensitivity in a wide variety of bird species show a region of maximum sensitivity between 1 and 5 kHz with a rapid decrease in sensitivity at higher frequencies. On the basis of this general measure, birds fall between two other major vertebrate groups: reptiles and mammals. Discrimination and masking data from birds include measures of frequency, intensity, and duration difference limens; critical ratios, critical bands, and psychophysical tuning curves. There are also data on temporal summation, temporal resolving power, and temporary threshold shift from noise exposure. Taken together these data suggest that, in the region of 1–5 kHz, birds show a level of hearing sensitivity similar in most respects to that found for the most sensitive members of the class Mammalia with avian performance clearly inferior above and below this range of frequencies. Possible exceptions to this general picture must include the echolocating oilbird and growing evidence that pigeons are sensitive to infrasound at moderate intensity levels. The relation among critical ratio, critical band, and intensity difference limenmeasures in the parakeet is similar to that described for the human, but the pattern of masking as a function of frequency is dramatically different from that observed in mammals. Examples of a correspondence between hearing sensitivity and vocalizations can be demonstrated in a number of species.
64(1978); http://dx.doi.org/10.1121/1.2004238View Description Hide Description
Because of their appeal as a modelanimal communication system, birds have become the subject of many studies of stimulus encoding in the auditory system. Our approach to the study of this encoding has been to characterize in detail the transformations which occur at various levels within the system. Because this approach is similar to that which we and others have taken in studying the mammalian auditory system, we can now make some quantitative comparisons between these two classes. Thus far our studies have been largely limited to the auditory nerve, and nucleus magnocellularis and nucleus angularis, the avian homologues of the mammalian cochlear nuclei. Response properties of avian auditory‐nerve fibers are generally quite similar to those in mammals. However, average discharge rates (both spontaneous and driven) are considerably higher in birds than in mammals. Although the sharpness of tuning in the “tip” region of avian auditory‐nerve tuning curves is quite similar to that in mammals, low‐frequency “tails” occur only at higher sound levels than in mammals, if at all. Response properties of cells in nucleus magnocellularis and nucleus angularis bear a relation to auditory‐nerve patterns which is similar to that of their mammalian homologues. Cells in nucleus magnocellularis exhibit properties which closely resemble those in the auditory nerve, whereas those in nucleus angularis show a similar increase in complexity to that which is found in mammalian posteroventral and dorsal cochlear nuclei. [Supported by Grant No. NS 12112 from NIH.]
64(1978); http://dx.doi.org/10.1121/1.2004239View Description Hide Description
The ability of an animal to localize sound is correlated with its ethological niche. Birds face a particularly difficult task in sound localization, since they must localize well in both azimuth and elevation: The azimuth of a target is of no use to an airborne predator unless it can also determine the target's elevation. Furthermore birds must perform sound localization with access to only a limited range of low sound frequencies (<12 kHz), with heads that provide little sound shadow, and with ears that have no pinnae and are close together. However behavioral, physiological, and anatomical data suggest that the auditory systems of birds are capable of extremely fine time resolution. Also, birds have elaborated a large, patent air canal connecting their two middle ears that might improve the directional properties of their ears. Finally, some birds have developed asymmetrical ears that cause interaural time and interaural intensity cues to assume different axes of symmetry. It is proposed that these adaptations permit birds to achieve a high level of sound localization ability, the best of which rivals, and may exceed that of man. [Work supported by NIH.]
- Session F. Engineering Acoustics I: Calibration and Transducers. (Part Précis‐Poster Session)
- Invited Paper
64(1978); http://dx.doi.org/10.1121/1.2004334View Description Hide Description
Various acoustic researches for telecommunication are performed in the Electrical Communication Laboratory, NTT. Among these, researches on acoustic standard apparatus, acoustic measurements,electroacoustic transducers, vibrating systems, acoustic materials, room acoustics, and telephone networks are included. A new standard condensermicrophone has been developed for precise soundmeasurement and sensitivity calibration of telephone sets. This new standard microphone, made of titanium alloy, has high sensitivity (−54 dB re 1 V/mgr;bar, high reliability, and wide frequency range (∼35 kHz). A precise calibration method using standard couplers, as well as a simplified calibration method using active coupler, are established. Research of room acoustics is important for telephone systems in the future, because the acoustic transmission characteristics of rooms may take an important place in the system. Transmission characteristics and the spatial correlation coefficients of various rooms are investigated. The results of these researches are especially useful in telephone loudspeaker design. Based on the results of various researches, several types of new telephone sets and systems are now being developed.
- Contributed Papers
64(1978); http://dx.doi.org/10.1121/1.2004381View Description Hide Description
A nearfield acoustic measurement technique for accurately computing the farfield radiation characteristics of underwater soundtransducers was developed, implemented, and evaluated. The analysis was based on evaluation of a form of the Helmholtz integral which utilizes a Green's function that vanished over the surface of integration, thereby requiring only knowledge of the nearfield acoustic pressure for computing the farfield radiation. An experimental program was conducted to provide corroboration of the technique. Details of the automated, digital, nearfield measurement instrumentation are presented. Comparisons between conventionally measured farfield properties of four different types of test transducers and the results obtained by using the nearfield technique are given. The results showed that excellent agreement was achieved for the radiation properties compared. For the directional responses, the nearfield technique matched the conventionally measured results over the minor lobe structure as well as over the major lobe structure of the pattern. The results also showed that absolute sound pressure levels and directivity indices could be ascertained accurately and with relative ease. [Work supported by NAVSEA 034.]
64(1978); http://dx.doi.org/10.1121/1.2004382View Description Hide Description
In this paper we describe an automated acoustical measurementsystem. The system includes three minicomputers and a number of microprocessors for control and data handling. Multiprocessors are used to simultaneously handle all the processing functions. Interaction with the operator and overall timing and control for the system is handled by the central processor. Two peripheral processors are used for high speed data computation and processing. Several microprocessors provide intelligent control functions for the system. A sophisticated software operating system is used to integrate the hardware into a useable and flexible system. The user is offered a wide variety of options for display and output of measurement data. The software is designed to make implementation of any of these options as easy and convenient as possible for the user. [Work sponsored by NAVSEA 06H4D.]
AN/FQM‐12(V) sonar test set. II: signal generation and processing for an automated acoustical measurement system64(1978); http://dx.doi.org/10.1121/1.2004383View Description Hide Description
This paper describes the signal generation and processing capabilities of an automated acoustical measurement system. The basic design goals for the signal generation and timing capabilities of the system were to provide the maximum flexibility for signal generation and reception while using sampling techniques that allow fast signal processing algorithms to be used in the data processing and analysis. The waveform and timing generator was designed to generate the conventional sinusoidal pulse waveforms used in many acoustical measurements along with special purpose arbitrary waveforms which can either be used directly as the transmit signal or to modulate the sinusoidal transmit pulses. The system timing technique allows a user to make simple single pulse measurements or to make multiple pulse measurements where data samples are summed either coherently or incoherently to maximize the signal‐to‐noise ratio. [Work sponsored by NAVSEA 06H4D.]
64(1978); http://dx.doi.org/10.1121/1.2004384View Description Hide Description
The accuracy of coupler calibration of condensermicrophones, such as MR112 and B&K4134, was tested. The coupler used was a new 1‐cm3 coupler [A. Suzuki and S. Yoshikawa, J. Acoust. Soc. Jpn. 28, 475–484 (1972)], as well as the 20‐cm3 a coupler attached with B&K adaptor DB0225. Calibrations were carried out at the frequencies 50–12 500 Hz by the 20‐cm3 a coupler and 50–30 000 Hz by the 1‐cm3 coupler. Pressure response levels calibrated by the reciprocity technique using both couplers showed very good agreement. If the theoretically calculated correction values [H. Miura and E. Matsui, J. Acoust. Soc. Jpn. 30, 639–646 (1974)] are applied to measured values, the differences of the response levels calibrated by both couplers are within 0.05 dB in the frequency range 100–10 000 Hz. It can be said that the method of precise coupler calibration of condensermicrophones has been achieved.
64(1978); http://dx.doi.org/10.1121/1.2004385View Description Hide Description
The authors devised a new detection method of measuring the location of a steel bar within concrete on the concrete surface through an electromagnetic impact driving method. Through this method, a steel bar within concrete is driven directly into vibration with occurred impulsive magnetic flux at a flat spiral coil set on the concrete surface. That is, a steel bar within concrete is regarded as a sound source. The location of a steel bar within concrete is determined by the measured propagation time within concrete of radiated sound from a steel bar and the sound velocity in the concrete block. The experiment on the detection of a steel bar at a depth of less than 25 cm under the concrete surface was performed. From these experimental results, this method is expected to be useful for the detection of a steel bar within concrete. Furthermore, the propagation characteristics of sound in the concrete block and driving conditions for a steel bar within concrete were also examined.
64(1978); http://dx.doi.org/10.1121/1.2004386View Description Hide Description
A method is described to determine changes in the sound levels of an acoustical system due to changes in the variables internal to the system as well as external to the system. The method involves analytical and experimental simulation techniques to determine various partial factors which are then superimposed to estimate the resultant sound levels as a function of a desired variable. A practical approach is suggested for the applications of the method by approximations to save time, effort, materials, etc.
A method for measuring electrostrictive properties of ultrasonic transducer material under high hydrostatic pressure64(1978); http://dx.doi.org/10.1121/1.2004439View Description Hide Description
The motional impedance or admittance method cannot be applied to a test transducer contained in a small non‐sound‐absorbing pressure tank, because admittance or impedance loop does not make a circle due to sound reflection at the tank wall. The method we used is to excite a bar‐shaped test transducer in a pressure tank into longitudinal vibration by the use of a mechanical driving system, and to observe short‐circuit current or open‐circuit voltage of the test transducer. A transducermaterial for high power use was taken as a sample. Electrostrictive stress constants e 31, h 31 and dielectric constant ε31 were measured at hydrostaticpressures from 1 to 600 atm. Vibrational velocity dependence of e 31 and h 31 was also measured, varying driving velocity level at the test transducer end as high as 80 cm/s. The results are that e 31 and h 31 become slightly large as hydrostaticpressure increases but show no appreciable velocity level dependence.
On the added mass matrix and acoustic pressure of multiple circular cylinders vibrating in a compressible fluid64(1978); http://dx.doi.org/10.1121/1.2004440View Description Hide Description
The linear two‐dimensional acoustic waveequation is solved for multiple circular cylinders vibrating harmonically in an infinite compressible fluid. The solution is expressed in terms of series of cylindrical wave functions. To satisfy the interface boundary condition of a particular cylinder, all cylindrical wave functions are transformed to the coordinates associated with that cylinder. The resulting equations are a system of algebraic equations for the undetermined coefficients, which are solved numerically by digital computer. The velocity potential, pressure, and force acting in each cylinder are then obtained in terms of these coefficients. The added mass matrix is found symmetrical and dependent on the wave number, the cylinder radius, and the distance and orientation between cylinders. On the surface of each cylinder the pressure field also depends on those parameters as well as the orientation of point on that surface. Numerical values of added mass matrix and pressure distribution are obtained for many cases.
64(1978); http://dx.doi.org/10.1121/1.2004441View Description Hide Description
An impulse technique for determining radiation impedance and radiation directivity of jet nozzles is discussed. Results for an unflanged pipe are compared with the theoretical results of Levine and Schwinger [Phys. Rev. 73, 383–406 (1948)] for the purpose of justifying the technique. Data are then presented to show the effect of nozzle size and jet velocity on both nozzle transmission and radiation impedance and radiation directivity. Conical nozzles are used and the results for 2‐ and 1‐in. diameter nozzles are compared with those for the 4‐in. diameter straight unflanged pipe. Effects of jet exit velocity up to 1300 ft/s are displayed and discussed in the light of available theory. Spectral energy is determined for the incident and reflected wave signals in the pipe, and the transmitted wave in the farfield and energy conservation for the system is discussed. Finally, it is shown that the test method can be usefully applied at frequencies above the plane mode regime.