bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns of activity in single auditory nerve fibers of the goldfish
Authors: Fay R. R.
Published: October 2005

The response of single fibers of the goldfish saccular nerve were recorded extracellularly in response to tonal stimuli. For each unit studied, quantitative measures of phase-lockking (period histograms) were made in response to several tonal frequencies, each presented at a wide range of sound pressure levels. The sensitivity and responsiveness of each unit were plotted as functions of frequency in terms of both spike rate modulation, and phase-locking criteria. Fibers showing little adaptation, high spontaneous firing rates, and low-pass frequency response characteristics were designated type II fibers, while those showing less spontaneous activity, greater adaptation and high-pass frequency characteristics were designated type I fibers, to correspond to an earlier classification [T. Furukawa and Y. Ishii, J. Neurophysiol. 30, 1377–1403 (1967)]. Within each classification, sensitivity, spontaneous activity patterns, phase-physical data on frequency analysis suggest that it is in the temporal patterns of spike activity, and not in the spatial patterns of spike rates that most auditory information is conveyed to the brain. [Work supported by the NSF.]
Effects of temperature on the response properties of auditory nerve fibers in the American toad (Bufo americanus)
Authors: Moffat A. J. M. , Capranica R. R.
Published: October 2005

While a number of studies have explored the effects of temperature on the electrical potentials in the inner ear, little is known about such effects on auditory nerve fibers. We therefore conducted a study of changes in the response properties of single auditory units in the VIIIth nerve of Bufo americanus as the animal's temperature was varied. Toads are opportune animals for such studies since they can tolerate a wide range of body temperature. While recording continuously from an individual fiber, the toad's temperature was varied by a Peltier plate to which it was secured. A total of 27 units in 4 animals was studied. As the animal's temperature was lowered, the best excitatory frequencies (BEF) of fibers from the amphibian papilla shifted downwards while their thresholds increased. In addition, both spontaneous activity and maximum firing rate to a tone at a unit's BEF decreased although its dynamic range remained approximately 30 dB above threshold, Fibers from the basilar papilla also showed a diminution in spontaneous activity and maximum firing rate. However, their BEF's and thresholds changed very little with temperature. These results suggest that the basis for frequency analysis differs between the two organs.
Temperature effects on single auditory nerve fiber responses
Authors: Eatock R. A. , Manley G. A.
Published: October 2005

Single-fiber activity in the cochlear nerve of Gekko gecko was monitored while raising the body temperature. Pure tone thresholds were measured repeatedly as the temperature rose until contact with the fiber was lost. Temperatures were monitored orally with a small sensor next to the contralateral cochlear duct. Frequency-threshold tuning curves of all fibers consistently shifted towards higher frequencies at higher temperatures. Temperature increments as small as 1°C raised a fiber's characteristic frequency (CF) by 50 to 150 Hz, and frequently augmented its sensitivity at CF by several dB SPL. The whole tuning curve shifted towards higher frequencies but did not significantly change shape. These changes are consistent with temperature effects on lizard cochlear microphonic [Y.L. Werner, J. Exp. Zool. 195, 319–352 (1976)], summating potential of mammals [J. A. Manley and B. M. Johnstone, J. Comp. Physiol. 88, 43–66 (1974)] and evoked potentials from lizard cochlear nuclei [H. W. Campbell, Physiol. Zool. 42, 183–210 (1969)]. The significance of these data for single-unit work and basilar membrane motion measurements is discussed.
Comparison of the response of the two-fiber populations in the auditory nerve of the alligator lizard
Authors: Turner R. G. , Nielsen D. W. , Teas D. C.
Published: October 2005

The basilar papilla of the alligator lizard (Gerrhonotus multicarinatus) contains two anatomically distinct hair cell populations. The apical population has unidirectional orientation and is associated with a tectorial membrane. The dorsal population has bidirectional orientation and free-standing cilia. On the basis of tuning curve properties, the primary auditory nerve fibers have been categorized into low (<0.9 kHz) and high (>0.9 kHz) CF populations. These two populations have been associated with the apical and basal regions of the papilla, respectively [Weiss, Mulroy, Turper, and Pike, J. Acoust. Soc. Am. 55, S84(A) (1974)]. The objective of the present study was to determine if other measures of the physiological response of the fibers could distinguish the two fiber populations. Action potentials were recorded from single, primary auditory nerve fibers in response to click, tone burst, and noise burst stimuli. The data indicate significant differences in the response of the two-fiber populations to the same acoustic stimulus. It is proposed that these physiological differences result primarily from the anatomical differences of the associated hair cell populations. [Work supported, in part, by NIH grants NS07287, NS06459, and NS05475, the Deafness Research Foundation, and Henry Ford Hospital.]
Forward and simultaneous tonal suppression of single-fiber responses in the chinchilla auditory nerve
Authors: Harris D. , Dallos P. , Kraus N.
Published: October 2005

Response patterns (PST histograms) of auditory nerve fiber discharges with two-tone stimuli were obtained. The two tones either overlapped (simultaneous suppression) or were temporally separated (forward suppression). The response elicited by a probe tone at the fiber's CF decreases when immediately preceded by a masking tone. It was found that the frequency/intensity combinations of effective maskers lie within the tuning curve of the fiber. In simultaneous two-tone suppression the frequency/intensity contours of the masker are broader than those observed in the forward suppression condition. The post stimulus suppression in firing below spontaneous rate, which is typically observed following maintained excitation, is suggested as the single-fiber substrate for forward suppression and masking effects observed in AP and psychophysics. [Supported by Grants from the NINCDS.]
Intensity functions of cortical auditory neurons in the awake monkey
Authors: O'Connor Thomas A. , Pfingst Bryan E. , Miller Josef M.
Published: October 2005

The relation between stimulus intensity and single unit activity was examined in the auditory cortex of unanesthetized monkeys trained to perform in an auditory reaction time task. Data was collected primarily under performance conditions, but nonperformance data was also acquired. Subsequent histology indicated that most recorded units were located in koniocortex and the lateral and caudal parakoniocortices [D. N. Pandya and F. Sanides, Z. Anat. Entwickl.-Gesch. 139, 127–161 (1973)]. In 70% of the units examined, discharge rate was a nonmonotonic function of stimulus intensity at best frequency. Thirty percent of the units had monotonic intensity functions. This proportion did not vary substantially with cortical location. Monotonic functions tended to rise less steeply from threshold as intensity was increased than did nonmonotonic functions. Monotonic functions also exhibited a wide spread of dynamic ranges, approximately half of which exceeded 50 dB. Dynamic ranges as great as 80 dB were seen in some monotonic units. Quantitative aspects of intensity functions, including slope, threshold, and discharge rate, are discussed as they relate to monotonic and nonmonotonic functions. Implications with respect to intensity coding in the cortex are also discussed. [Work supported by NIH Grants NS-08181 and GM-00260.]
Developmental changes of susceptibility to temporary threshold shift in hamsters
Authors: Bock G. R.
Published: October 2005

The magnitude of temporary threshold shift (TTS) and the time course of recovery of TTS were studied in young hamsters. Animals aged 15, 28, 40, 55, or 85 days were anesthetized with urethane and a sound speculum was sealed around the left tympanic ring. Evoked potentials in response to tone bursts were recorded from an electrode in the right inferior colliculus and thresholds for detecting the computer-averaged neural response were measured before and for 100 min after a 10 minute presentation of a continuous tone (3 kHz, 110 dB SPL), Mean threshold shifts at 4 kHz, 1 min post-exposure, were 16, 35, 41, 28, and 25 dB in the 15-, 28-, 40-, 55-, and 85-day-old groups respectively. Threshold shifts recovered within 100 min in 15- and 85-day-old animals, but required considerably longer to recover in the other age groups. The data suggest that young hamsters pass through a critical period of susceptibility to TSS. Consideration of the development of normal thresholds suggests that the critical period may be dependent on developmental changes within the cochlea. [Work supported by the Deafness Research Foundation.]
Neural correlates of auditory plasticity during classical conditioning in the rabbit
Authors: Lonsbury-Martin B. L. , Martin G. K. , Schwartz S. , Thompson R. F.
Published: October 2005

Multiple units were recorded from auditory structures during the classical conditioning of the rabbit's nictitating membrane response. Stainless steel insect pin electrodes (50 μm) were used to record bilaterally from small groups of cells in either the cochlear nucleus, inferior colliculus, or medial geniculate. Although all electrode placements responded to the white noise conditioned stimulus, most of these responses were labile in that peristimulus-time histograms indicated considerable variability in the response patterns of the cell groups over trial blocks. In general, onset and sustained responses to the conditioned stimulus tended to habituate during the 117-trial acquisition session. However, a number of subjects with medial geniculate or inferior colliculus placements showed an increase in the sustained response to the conditioned stimulus associated with acquisition of the learned response. The relationship of the observed neural changes to the anatomical location of electrode placements is considered. [Supported by grants from NSF and NINCDS.]
Politics and noise control
Authors: Way R. , Perez A. E.
Published: October 2005

The early 1970's saw a proliferation of noise control legislation at all levels of government in this country. Many of these efforts failed and continue to fail, amid continuing public support, as a result of the political system. The 1971 Minnesota Legislature mandated the Pollution Control Agency (PCA) to control noise that “may be injurious to human health or welfare, animal or plant life, or property, or could interfere unreasonably with the enjoyment of life or property.” This mandate is supported by one of the most comprehensive examples of noise control legislation in existence. The PCA in responding to the mandate was faced with a State political system burdened with past pollution control legislation, and leery of major commitments to a program which lacked the federal support of previous efforts. In addition, the political system was under pressure from powerful political lobbies to stop any further environmental programs. The noise control program is now in its maturing stages, with results toward a better environment becoming evident. The legislative mandate and historical key events of the program will be discussed.
Community response to aircraft noise: level versus number relationship
Authors: Connor William , Patterson Harrold
Published: October 2005

Response behavior in terms of a typical scale of individual annoyance was examined for various categories of level and number of aircraft operations. The data base was obtained from social surveys and acoustical measurements around nine airports in the USA during the period 1967–1971. For the sample as a whole, adverse response tended to increase with the energy-mean perceived noise level of aircraft operations; in relation to numbers of operations, however, response tended to peak in the 100–200 operations per day category rather than increase monotonically. This result does not conform to certain accepted response models, suggesting a need to develop and test other models. [Work supported by NASA.]
The relationship between aircraft noise annoyance and duration above specified noise levels
Authors: Hughes T. L. , Mabry J. E.
Published: October 2005

Relationships were investigated between community response to airport noise and dwell time noise determination methods. Two community response measures were employed. One involved whether or not the respondent disliked his neighborhood due to aircraft noise and the second measure was concerned with whether or not airport noise was perceived as the “MOST serious problem in this community right now?” Seven dwell-time levels involving the amount of time that the noise was equal-to-or-greater-than a specified level were investigated. These seven dwell-time levels were 65 to 95 dBA in 5-dBA increments. A method for completely describing the noise at each respondent's home was developed and utilized. Some conclusions are as follows: (1) The dwell-time approach is an effective method for quantifying aircraft noise impact. (2) Dwell-time determinations based on a particular level do not accurately predict dwell-time determinations at another level. (3) For detailed land use planning, a method involving cumulative noise impact at a particular point has high utility. [FAA-EQ supported.]
Airport noise: A monitoring program and the first steps toward its solution
Authors: Perez A. E.
Published: October 2005

Airport noise is easily the most intensive, publicized, and emotional noise problem facing urban dwellers. The problem is also a magnificent example of federal inaction, and technical doubletalk as a result of its complexity. The Minneapolis—St. Paul International Airport, even though singular in innovative noise abatement procedures developed under public pressures, continued to unacceptably impact the life and property of its neighbors. In facing the problem, the Agency encountered: lack of successful case histories, unmeasurable criteria, unaffordable instrumentation, and noncooperation by federal agencies and industry. Roadblocks were overcome steadily: Noise Standards were adopted in November 1974; automatic noise monitors were developed at reasonable prices ($200 per unit) and 33 units purchased; a monitoring program with the help of 350 families was implemented, the impact of the problem was defined acoustically and demographically, unique operational characteristics of airline companies uncovered and documented and an objective dialogue with the source started. State Regulations on this problem are being developed to control areas where voluntary compliance is not expected and to supplement recent legislative action.
Variables to be considered when predicting the Lcdn of blast noise
Authors: Lewis N. D. , Luz G. A.
Published: October 2005

The C-weighted day-night average sound level (Lcdn) is currently being used to evaluate the impact of blast noise on nearby communities. When predicting these Lcdn values, several variables must be considered. The difference between the linear peak level and C-weighted slow level is not constant as implied in the criteria, but varies with distance from source and weapon-charge combination. The prediction of the level must also consider more than spherical spreading, it must consider the wind direction and velocity. The time of day when the blast occurs must also be considered, as temperature inversions, occurring primarily when the surface is cooler than the air above it, cause increased sound levels. A final variable considered is the charge weight-sound level relationship which also varies between weapons. The effects of these variables on the sound level have been observed in blast noise measurements at distances from 150 to 5000 m.
Effects of noise induced permanent threshold shift on single units in the cochlear nucleus
Authors: Salvi R. , Henderson D. , Hamernik R.
Published: October 2005

Chinchillas were exposed to nonreverberant impulse noise (50 impulses, 1/min, 155 dB p.e. SPL, 1-msec A duration) and allowed to recover for at least 40 days following the exposure. Single neurons were subsequently sampled from the dorsal and ventral cochlear nucleus. Many units from the noise exposed animals had abnormally high thresholds and broad tuning curves. Due to the shallow slope of the low-frequency tail of the tuning curve, some units gave responses that were exclusively inhibitory. In other units, the threshold for the inhibitory area was 30–40 dB lower than the threshold for the excitation area. Many of the high-threshold units also showed abnormally high rates of spontaneous activity. The results of single unit experiments are compared with the nature and extent of the cochlear lesions obtained using the surface preparation.
Patterns of impulse noise-induced TTS during a work-week exposure
Authors: Henderson D. , Hamernik R. P. , Hynson K.
Published: October 2005

Five monaural chinchillas were exposed to a repetitive and reverberant impulse noise for a period of five days, eight h/day at a rate of 1 impulse/sec. The average peak over pressure within the holding cage was 113 dB SPL and the B duration was 160 msec. Auditory thresholds were estimated before and after each exposure using the AER technique. Thresholds were followed for 30 days following the last exposure; the animals were then sacrificed for the surface preparation histology. A clear oscillation in the animal's threshold emerged; high frequencies (4, 8 kHz) were shifted 40 dB after the 8-h exposure and recovered 25 dB following 16 h of quiet. Low frequencies (0.25, 0.5 kHz) were shifted 22 dB after the 8-h exposure and recovered 25 dB following 16 h Paradoxically, the low frequencies took longer to recover from an initially lower level of TTS. In general, there was no evidence of any accumulation of TTS over the four-day period. The final audiograms will be correlated with the cochlear histology.
Effects of noise exposure on the cochlea and neurons of the inferior colliculus
Authors: Melichar I. , Popelár̆ J. , Syka J.
Published: October 2005

Guinea pigs were exposed for 30 or 60 min to high-intensity stimuli (1/3-octave band noise centered at 1 or 2 kHz tone, intensity from 130 to 145 dB SPL). Several electrophysiological measurements were made in the cochlea and in the inferior colliculus before and after the exposure. Potassium concentration in the perilymph of scala vestibuli (measured with ion-selective double barrel microelectrodes) which was 3.07 ± 0.50 mm K+ in the control group of nonexposed animals, increased after the exposure to 4.70 ± 1.55 mm K+. Threshold tuning curves for the inferior colliculus neurons were elevated by about 30–50 dB, when compared with the pre-exposure levels. The threshold values gradually decreased, reaching the pre-exposure level approximately after 48 hours. Similar time course was observed in the endochochlear potentials, which was decreased after the exposure. Despite the threshold elevation the excitability of neurons ot polarizing currents was not greatly affected by the exposure.
Auditory sensitivity of the albino rat
Authors: Kelly Jack B. , Masterton R. Bruce
Published: October 2005

Auditory sensitivity of the albino rat was determined using the conditioned suppression of licking technique. The rat was found to have a range of sensitivity to pure tones from 250 Hz to 80 kHz at 70 dB SPL. The point of maximum sensitivity was 8 kHz closely rivaled by higher frequencies up to 38 kHz. Withing this band, tones were detectable at sound pressures from 2–7 dB SPL. For frequencies above 38-kHz sensitivity rapidly decreased at a rate of about 50 dB per octave. For frequencies below 8-kHz sensitivity decreased at a rate of about 20 dB per octave. The audiogram supports previous evidence of good hearing around 32–38 kHz [G. Gourevitch and M. H. Hack, J. Comp. Physiol. Psych. 62, 289–291 (1966)], but does not support the idea that the albino rat's hearing is narrowly tuned to this range. Thus, the sensitivity of the albino rat to these frequencies reflects the broadly tuned high frequency hearing which is generally quite good in small mammals, rather than representing a specialized feature of its auditory system. [Supported by grants from NRC and NIH.]
Periodicity pitch perception in cortically ablated cats
Authors: Chung David Y. , Colavita Francis B.
Published: October 2005

Six cats were first trained to discriminate frequency and shown to perceive periodicity pitch. They were then operated bilaterally with part or most of the auditory cortex aspirated out. The areas AI, AII, and Ep were ablated in two cats. They were still able to relearn frequency discrimination and perceive periodicity pitch with little amnesia. The same two cats were operated again with insular-temporal cortex (I-T) removed. Two more cats also had the areas AI, AII, Ep, and I-T removed in one operation. Two of these four cats relearned the preoperative discrimination although considerable postoperative training was required. The other two cats showed no signs of relearning. The remaining two of the six cats had I-T lesions only. None of them acquired the preoperative discrimination. Histological examination showed incomplete ablation of the I-T areas near the rhinal fissure in the two cats which relearned the preoperative discrimination. The experiment was unable to resolve the cortical areas for the pure-tone and the periodicity-pitch discrimination. The fact that both kinds of discrimination occurred together may imply that the cortex is not an essential part of the auditory system for either kind of discrimination.
Designing a community noise regulation
Authors: Goodfriend L. S. , Clark E. M. , Ober S. M.
Published: October 2005

The officials of the Township of East Brunswick, New Jersey, set out to establish a noise control regulation for their municipality that would meet the health and welfare needs of its residents and still provide a suitable climate for business and industry, East Brunswick is a municipality of 23.5 square miles, having a residential population of 36 790, and land uses including farming, industrial plants, strip commercial zones along a major state highway, and a major turnpike. Major steps of the program to develop a regulation were physical examination of the township and its land uses; review of the existing master plan; determination of the health-related concepts of noise exposure; development of a rationale for selecting a noise descriptor permitting enforcement by suitably trained local officials; determination of present ambient sound levels; and development of the regulation structure, limits, and enforcement techniques. The new regulation is based on octave band levels not to be exceeded at the boundaries of each of three land use classes formed from groups of existing land use zones. Where sounds are intermittent, duration-level tradeoffs are permitted up to a limit of 15 dB.
Stimulus correlates in the perception of voice onset time (VOT): I. Discrimination of the time interval between tone bursts of different intensities and frequencies
Authors: Divenyi P. L. , Sachs R. M. , Grant K. W.
Published: October 2005

In a four-level 2AFC paradigm, trained subjects had to discriminate time intervals that were marked by tone bursts of unequal duration (10 and 100 msec). Time differences discriminable at the d′ = 1 level, ΔTThresh, were determined in the 10–100-msec range of time intervals (onset to onset). When the frequencies and intensities of all markers were held constant (1 kHz and 86 dB SPL), ΔTThresh was a monotonic function of T. This relation became non-monotonic when the level of the first marker was decreased to 36 dB SPL or as the two marker frequencies were made different from each other by two octaves. Thus, a discrepancy in either the level or the spectrum of two time-marker sounds may constitute an acoustic basis for the nonmonotonic VOT discrimination functions, despite the fact that the depth of the local minimum found in the present data is less than that observed in VOT experiments. [Supported by a grant from NINCDS.]
The voicing boundary as a function of F2 and F3 transitions and fundamental frequency
Authors: Repp Bruno H.
Published: October 2005

It is well known that the voice-onset-time (VOT) boundary for synthetic stop consonants shifts towards longer VOT's as place of articulation shifts from front to back, even if all parameters of the signal except VOT and the starting frequencies of F2 and F3 are held constant. Is this a phonetic effect contingent on a decision about the place feature, or is it an auditory effect that is somehow dependent on the spectrum at syllable onset? In order to decide this question, F2 and F3 transitions were varied in a number of steps along a “place continuum,” and the VOT boundary was determined at each step. The function relating the VOT boundary to the place continuum should be flat within place categories and show jumps at the category boundaries if the effect is phonetic, but it should be monotonically increasing if the effect is auditory. Neither hypothesis has been supported by the data so far, which show the function to be generally increasing but strongly nonmonotonic, with a number of seemingly haphazard but statistically reliable peaks and valleys. A radically different pattern (with the same general characteristics) is obtained if the fundamental frequency of the stimuli is changed. Further research on the acoustic basis of the effect and its perceptual and methodological implications will be reported.
An acoustic correlate of syllabicity in english
Authors: Semiloff H.
Published: October 2005

The purpose of this research was to test three hypotheses (1) Increasing the duration of a nonsyllabic segment will cause the segment to be perceived as syllabic. (2) The perception of syllabicity is categorical. (3) Listeners will differ in their labeling responses to stimuli when told to judge them in different speech styles. Seven words were synthesized: “blow,” “plight,” “dress,” “crest,” “prayed,” “broke,” and “sport.” The steady-state portion of the /l/ or the /r/ (for “sport,” aspiration Of /p/) was lengthened in 10-msec increments. Subjects were asked to decide whether the word was monosyllabic or disyllabic: “blow-below,” “plight-polite,” “dress-duress,” “crest-caressed,” “prayed-parade,” “broke-baroque,” and “sport-support.” Five groups of 15 listeners each participated in the labeling task. Four groups heard the stimuli with a precursor frame, “The word you will hear next is ___” in one of four speech styles: formal-slow, formal-fast, casual-slow, casual-fast. Each group was told to judge the words according to the criterion of being spoken in one of the designated styles. The fifth group heard the stimuli with no precursor and received no style instructions. Results showed that (1) increased durations of /r/ and /l/ did result in perception of the words as disyllabic, but increasing the duration of aspiration in “sport” did not; (2) perception of syllabicity appears to be categorical; and (3) there were no statistical differences among the four speech styles. [Work supported by NSF SOC75-10043.]
Stimulus range as a determinant of phoneme boundaries along synthetic consonant continua
Authors: Studdert-Kennedy Michael
Published: October 2005

Brady and Darwin (see Darwin, C.J. The Perception of Speech, in E.C. Carterette, and M.P. Friedman, Handbook of Perception, Academic, New York (in press), Vol. 7, report shifts in the phoneme boundary along a synthetic voicing continuum as a function of the range of stimuli presented within a test. The present study reports comparable shifts along synthetic voicing and place of articulation continua. Implications for the interpretation of adaptation boundary shifts are considered.
Interaction between rhythmic prominences and intonation
Authors: Boomsliter Paul C.
Published: October 2005

Students played scales on equipment which provided altermative tunings of scale notes. When instructed to dwell on one or another note, they chose different tunings for the subsequent notes of the scale. This suggests that when a note is made prominent, it is likely to establish a second tonal center to which later intonations are related. Thus the rhythmic structure of a melodic phrase interacts with pitch choices in performance.
Balancing the scales for music and speech
Authors: Burns E. M. , Carney A. E. , Ward W. D.
Published: October 2005

The results of our experiments on the identification and discrimination of musical intervals, along with the results of experiments by other investigators, are interpreted with regard to the possible “natural” basis of musical scales. We have concluded, primarily from basic differences in the perception of intervals by musicians and nonmusicians, that there is little evidence for the existence of “natural” interval categories, either in the sense of being innately determined by characteristics of the auditory processing system, or in the sense of early learning of the relations between partials in natural sounds. In light of the fact that many of the characteristics associated with the perception of speech, e.g., robust categorical perception, adaptation, and dichotic ear advantage, are also evident in the perception of musical intervals, the general question of the relationship between music perception and speech perception is also discussed.
Perceptual space of musical structures
Authors: Carterette E. C.
Published: October 2005

Loudness or pitch can be scaled in a space of one dimension. Timbre is multidimensional. The timbre of a musical sound or voice depends upon its time-varying spectral envelope and periodic fluctuations of amplitude or fundamental frequency. The strengths and weaknesses of scales in describing aspects of tone sensation are contrasted in the light of experiment and theory, both old and new. Multidimensional examples are perceptual spaces of voices and musical structures. Unidimensional examples are the standard scales of loudness and pitch. The adequacy of these is questioned by some recent work done with Norman H. Anderson and based on functional measurement theory. Thus, in one series of experiments, subjects judged loudness averages and differences of noise arrays. The resulting interval scale indicates that loudness is the one-third power of sound pressure. New work on loudness and pitch scales obtained in bisectioning tasks will be presented.
Migration of reflection seismic data: Two approaches
Authors: Larner K. L. , Hatton L.
Published: October 2005

A conventional reflection seismic record section displays data only as passing wavefield recorded at points on the earth's surface. In regions of complex geology, this display may bear little resemblance to a cross-section of subsurface reflectors. Migration is the technique used to transform such a wavefield into a reflectivity display. Different migration methods are derived from either an integral or differential form of the scalar wave equation. In particular, a matched filtering technique involving summation of amplitudes along diffraction hyperbolas is founded on the integral form, and a finite-difference method pioneered by Jon Claerbout, Stanford University, approximates direct solution of the differential form. After discussing fundamental assumptions required for implementation of the two migration approaches, this paper focuses primarily on comparison migrations of both synthetic data and of marine and land profiles. For good data of modest spatial dip, the two approaches produce similar results. However, the seismic trace spacing (receiver group interval) is found to play different, but fundamental, roles in governing the accuracy and signal-to-noise quality of both types of migration.
Performance evaluation of a high-resolution sub-bottom profiling system
Authors: Watters B. G. , Barger J. E.
Published: October 2005

The design and performance of a modern digital high-resolution sub-bottom profiling system are reviewed. The system is designed to identify drilling hazards in about the first 3000 ft of sea floor. Performance comparisons with a conventional active sonar are made using metrics such as figure of merit. The sound source is a sparker; the receiver a towed line array. There are two stages of signal processing: the first stage is applied to each hydrophone channel, and the second stage in the combination of all channels. The first stage includes pulse compression (zero phase least-squares Wiener filtering using a source monitoring hydrophone system), the removal of surface-images (“deghosting”), and the reduction of bottom-surface multiple reflections (“dereverberation”). Two near-field moving-focus beam steering second stages are compared; CDP (common depth point) stacking and Tucker et al.'s within-pulse electronic sector scanning. Typical sub-bottom records will be shown and the effectiveness of various processing steps illustrated. Also discussed are techniques for quantifying reflection coefficients to aid in lithologic interpretation and of “seismic modeling” to help unravel records with overlapping returns.
Role of the stationarity equation in linear least-squares estimation, spectral analysis and wave propagation
Authors: Pusey L. C. , Baggeroer A. B.
Published: October 2005

We develop the properties of the innovations representation for continuous-time stationary processes and consider applications to spectral estimation and the description of wave propagation in a lossless nonuniform medium. Both applications are based on the Levinson recursion for the causal least-squares estimation filter and the continuous-time counterpart of this recursion, the stationarity equation. In the first application, we develop an unconstrained representation of positive definite extensions by observing that the stationarity equation completely characterizes the least-squares estimation filter for stationary processes. This representation is incorporated in a noval approach to spectral estimation whereby the maximum entropy method is generalized so as to include arbitrary positive definite extensions of the estimated covariance. In the second application, we observe that the stationarity equation is descriptive of wave propagation in a lossless nonuniform medium and use this fact to obtain an interesting time-domain solution of the nonuniform wave equation. The solution is an extension of discrete-time results in seismology concerning acoustical wave propagation in a layered medium.
Nonlinear acoustics of water-saturated marine sediments
Authors: Bjørnø Leif
Published: October 2005

Interest in the acoustic qualities of water-saturated marine sediments has increased considerably during recent years. The use of sources of high-intensity sound in oil propsecting, in geophysical and geological studies of bottom and subbottom materials and profiles and recently in marine archaeology has emphasized the need of information about the nonlinear acoustic qualities of water-saturated marine sediments. While the acoustic experiments and theoretical investigations hitherto performed have concentrated on a determination of the linear acoustic qualities of water-saturated marine sediments, their parameters of nonlinear acoustics are still unexplored. The strong absorption, increasing about linearly with frequency, found in most marine sediments and the occurrence of velocity dispersion by some marine sediments restrict the number of nonlinear acoustic test methods traditionally available for fluids to a few being used for a determination of the nonlinear acoustic parameters of water-saturated marine sediments. These test methods, comprising static, thermodynamic and finite-amplitude wave distortion and absorption methods, aiming at a determination of B/A for marine sediments, are given a critical evaluation with emphasis put on limitations in their applicability. B/A-values of some marine sediments—quartz medium and fine sand, silt, and clay—characterizing the seabed of the Danish archipelago and measured in our laboratory by means of the test methods discussed are given and are compared with nonlinear acoustic qualities determined through small-scale explosion tests performed in the sediments. Sources leading to possible deviations between test results arising from prospective in situ measurements and from measurements carried out under laboratory conditions are discussed.
Geometrical and environmental constraints single-channel seismic record interpretation
Authors:   Sea Floor Division, Naval Oceanographic Laboratory, Naval Ocean Research and Development Activity, Bay St. Louis, MS 39520
Published: October 2005

Despite the fact that much better seismic data are presently being collected in the deep oceans than was thought possible only two years ago, the present bulk of qualitative and quantitative information about the structures and sediments of the ocean basins resides in the estimated 10 million track-kilometers of archived single channel seismic data. An enormous amount of invaluable information can be extracted from this resource if the geophysicist/geologist considers the limitations placed on the interpretation of the data by the conditions under which they were collected. The identification of multiples, diffractions, bubble pulses, and velocity effects must be accomplished before the effects of vertical exaggeration can be removed, true dips calculated, features migrated to their true position, and reflector separations more closely approximated. Examples show how each of these data processing steps can be accomplished.
Effective low-frequency geoacoustic properties of ocean sediments inferred from acoustic reflectivity measurements and corresponding regional geological data
Authors: Dicus R. L. , Anderson R. S. , Diachok O. I.
Published: October 2005

Acoustic reflectivity measurements were made at five deep ocean sites and processed for the ocean bottom impulse response at low frequencies (<200 Hz). Some of the essential features of the acoustic reflectivity at each of the sites were modeled in terms of a geoacoustic model consisting of a single thick (>50 m) sediment layer with a sound velocity gradient. The parameters for the model, viz., layer thickness, sediment interfacial sound velocity, and average gradient, density, and attenuation, were evaluated by theoretical analysis of the computed impulse responses. A compilation and analysis of the existing regional geological data from sources as gravity cores, deep drill cores, sonobuoy measurements, and seismic profiler records were also made to develop predictions of the model parameters. The sensitivity of acoustic bottom loss functions to variations in sediment parameters is discussed in view of the generally small differences obtained between the geological predictions and the acoustically inferred values.
Toward a quantitative near-bottom seismic profiler
Authors: Tyce Robert C.
Published: October 2005

This paper describes the development and application of a system for quantitative near-bottom seismic profiling at 4 kHz. Developed as part of the Deep-Tow Instrumentation System of the Marine Physical Laboratory, this system represents a capability which is relatively unique in terms of lateral resolution. This capability was developed in order to observe small-scale horizontal variations in acoustic reflectivity of the sea floor as well as similar properties for shallow, layered structures in bottom sediments. The system provides real-time computer processing and quantitative displays of processed data in several forms. These displays include a high-resolution grey scale display of equivalent plane wave pressure (compensating for Fish altitude), a three-dimensional contourogram display of equivalent intensity, and a plot of integrated equivalent energy for travel time sections (typically corresponding to 0–5 and 5–55 m into the bottom). These quantitative displays provide a real-time capability for mapping reflectivity of the sea floor and subbottom reflectors within a survey area and for estimating acoustic attenuation in marine sediments from observations of layer reflectivity as a function of depth of burial. Such determinations of attenuation can be made directly from the composite computer display which is produced on a facsimile recorder. The data from this system suggest that small-scale variations are common to many areas of the sea floor, with poorly explained variations of up to 10 dB over lateral distances of less than 50 m. Values of effective attenuation determined by this system show good agreement with values measured directly in the San Diego Trough, and suggest unusually low values for highly calcareous sediments on the Carnegie Ridge.
Electronically steered parametric transducer with variable frequency
Authors: D.W.
Published: October 2005

Using digital techniques, the beamsteering and signal-generation electronics for a parametric array can be packaged in a smaller volume than the array itself. This leads to a new concept for transducers in which these electronics are considered to be part of the transducer. Such a steerable parametric transducer was designed by APL and proper operation was demonstrated during in-water tests in June of 1975. The drive waveform for the transducer was generated by pulse width modulating a 21-kHz square-wave carrier to produce two primary drive frequencies. The difference freqeuncy (nominally 5 kHz) generated by nonlinearities in the water could be held at a particular frequency or could be readily chirped. Electronic beamsteering in two dimensions was achieved by providing a variable time delay for each element of a 2-dimensional 61-element array. The variable delay was achieved by varying the rate at which the modulated carrier was clocked through a matrix of shift registers. The nonlinear beam could be steered to a particular angle or scanned by linear variation of the clock frequency. [Work supported under Navy Contract NO0017-72-C-4401.]11
Finite-amplitude radiation fields of a plane-piston projector
Authors: Fenlon F. H. , Kesner J. W.
Published: October 2005

A new form of Burgers' equation for a plane-piston projector which unites the previously established plane and spherical waveforms [D,T. Blackstock, J. Acoust. Soc. Am. 36, 217–219(L) (1964)] will be considered. One of the most significant features of this equation is its ability to describe the amplitude-dependent transformation of purely spherical shock waves to mixed plane-spherical shocks, and finally to purely plane shock waves which exhaust themselves via thermoviscous and finite-amplitude losses within the nearfield region of the projector. The effect of such transitions on the harmonic fields of an initially monotonic finite-amplitude wave will be reviewed. On the basis of recent experiments [P.J. Welton, private communication], it will also be shown that the new equation provides a much more accurate representation of difference-frequency radiation within the “nearfield” of low-frequency “diffraction-limited” parametric arrays than certain alternative approximations. [Work supported by ARPA.]
Experiments with cavitating parametric sources
Authors: Moffett Mark B. , Konrad William L.
Published: October 2005

A cavitating parametric source utilizes a field of collapsing cavitation bubbles created by an intense two-frequency primary sound field. Since the cavitation zone is modulated at the difference frequency, this frequency (and its harmonics) is generated. The beam pattern is determined by the shape of the cavitation zone while the source level depends on the size of the zone. Experimentation with a number of sources utilizing face cavitation and remote cavitation has resulted in a better understanding of the performances of these devices. Cavitation thresholds for pure-tone and dual-frequency primary excitation, have been found to be nearly identical. [Sponsored by Naval Material Command.]
Ultrasonic-transducer power output by modulated radiation pressure
Authors: Greenspan M. , Breckenridge F. R. , Tschiegg C. E.
Published: October 2005

We have set up and are using an apparatus for the measurement of total sound power output of a piezoelectric transducer radiating into water. This apparatus combines the better features of previously used methods which depend on radiation pressure. The input is modulated at a low frequency and the output power is intercepted by an absorbing target which experiences a force at the modulating frequency. The target is mounted on the armature of an electromagnetic microphone provided with an independent coil through which a current at the modulating frequency is adjusted in amplitude and phase, either manually or automatically by feedback, to arrest the motion of the armature. Under these conditions the force depends only on the current, and the apparatus can be calibrated using direct current and dead weights. It is thus absolute. In practice, the carrier frequency is swept over any part of the range 1–80 MHz while a recording of power output versus frequency is made. Examples of curves from normal and defective transducers will be shown. Other applications, as in medical dosimetry will be discussed.
Unique Properties of an Open-Plan Auditorium
Authors: Pirn Rein , Bollinger Jeffrey E.
Published: October 2005

An architecturally open concept was adopted in the design of a 500-seat auditorium for a new school. The audience is seated on four shallow tiers that are adaptable for dining. The space is distinguished by a tall well over the forward seats, beyond which the ceiling is very low. At the back and sides, the arena is open to the student commons. Above and behind the stage, it is open to a spacious mezzanine. Deliberate acoustical provisions include absorptive finishes, lockers that act as barriers, a retractable curtain in place of a rear wall, reflectors to help stage-audience communication, and controlled background noise. Investigations reveal several unique properties: short but remarkably uniform reverberation times, averaging 0.72 sec; distance-depedent loudness that imparts a sense of dissimilar room size, depending on seat location; excellent intelligibility of stage sounds, with an average AI of 0.91 for raised voice; and excess attenuation of extraneous sounds on the order of 10 dB.
Acoustics, electroacoustics, and electronics in the ATLAPA Trade Show and Convention Center
Authors: Sepmeyer L. W. , Walker B. E. , Augspurger G. L.
Published: October 2005

The ATLAPA Trade Show and Convention Center now under construction in Panama City is a twenty-million dollar facility incorporating a 3000 seat multi-purpose auditorium, little theatre, general purpose exhibit area, meeting rooms, rehearsal spaces, etc. Acoustical design features and electroacoustic systems will be breifly described. Attention will be concentrated on (a) acoustical characteristics of the auditorium and exhibit hall in relation to usage as well as architectural and cultural constraints, (b) interrelated variable acoustics and sound reinforcement facilities in the main auditorium, (c) performance requirements for a multiple-use sound installation in the exhibit area, and (d) specially designed six-channel wireless translation facilities available for simultaneous use in nine contiguous areas.
The architect's aspirations in auditorium design
Authors: Williams Terence J.
Published: October 2005

Good sound, good sightlines, and intimacy are probably the most sought after requirements of any multipurpose auditorium. How these goals were achieved in the 1300 seat “surround” hall for the University of Victoria was the result of a very close collaboration between all of the consultants, structural, mechanical, plumbing, electrical, acoustical, and theatrical. Acoustical design goals for full scale music presentations midfrequency reverberation time 1.8–2.0 s fully occupied. Desired speech reverberation time 1.5 or lower. Background noise criteria for auditorium PNC 15–;20. Excellent sight lines were demanded from all seats. Various seating configurations were experimented with in model form. Movable reflecting clouds were incorporated and variable acoustical absorbing banners utilized. Slides, photographs, and perspective drawing available.