R&D Report 1966-04 : Acoustic tests on the Walker Memorial Hall, Birmingham. C.L.S. Gilford, T.J.B. Smith Acoustic tests carried out before and after modifications to the Walker Memorial Hall, Birmingham are described. Floor resonances which caused unacceptable musical quality satisfactorily removed.
Topics: reverberation, measurements, floor, studio, decay, accelerometer, cubicle, acoustic, resonances,...
This report is an extension of TRG's previous surface ship bottom bounce sonar prediction model to include the case of direct path propagation both to the potential target and reverberation sources. The tenets of valid sonar prediction are unchanged: in addition to an accurate estimate of the target echo level, one must include all significant reverberation components and sonar noise level to successfully forecast the sonar performance. The scattering sources for the surface duct problem are...
Topics: DTIC Archive, Novick, A., Seegal, R., Ginsberg, S., CONTROL DATA CORP MELVILLE NY TRG DIV, *SOUND...
Photographed on: 06/15/98. -- Radiated susceptibility test of e evaluation Boeing EDP (Engine Data Processor) per DO-160 procedure. In building 1220, Semi-Anechoic Facility.
Topic: TEST FACILITIES -- REVERBERATION CHAMBER
The thesis explores the phenomena unique to echo-ranging with a source widely separated from the receiver. In an asset-austere era of antisubmarine warfare, this technique serves as a tactical advantage, particularly in the passive tracking of a submarine. Particular emphasis is placed on the terms of the sonar equation most affected by the bistatic geometry: Reverberation level and target strength. The research is particularly applicable to ongoing NATO and Naval Laboratory work involving the...
Topics: DTIC Archive, Harvey,Lawrence Michael, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *Bistatic sonar,...
One-third octave band background noise and reverberation time measurements were conducted in the Exterior Effect Room (EER) at the NASA Langley Research Center. The related overall acoustic absorption of the room was calculated. The acoustic field in the room was characterized. Reverberation time measurements were performed using the integrated impulse response method. The results were compared with independent measurements using the interrupted noise reverberation time method and different...
Topics: NASA Technical Reports Server (NTRS), REVERBERATION, BACKGROUND NOISE, ACOUSTIC ATTENUATION,...
8
8.0
Sep 19, 2011
09/11
by
Daniel Bartsch
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Daniel Bartsch on the book Reverberation
Topics: Daniel Bartsch, the book, Reverberation
Naval Postgraduate School
2
2.0
Jan 31, 2021
01/21
by
Ball, Ernest Charles; Carlson, John Algot
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Acoustic backscattering from a random rough water surface has been studied experimentally to test the application of two scattering theories, a statistical description and a resonance approach. The rough surface was created by wind agitation over an anechoic tank. The wave height distribution was measured with a resistive probe and the wave slope distribution by optical glitter detection using a photocell. The distributions of backscattered sound pressures were recorded for surface roughnesses...
Topics: Scattering, Backscattering, Acoustic scattering, Rough water surface, Wave height distribution,...
This report describes a study in which several aspects of the discrete time Neyman-Pearson detector are investigated using experimental acoustic data. The problem considered is that of detecting a known signal from an active sonar operating a reverberant environment. The noise background consists of sonar returns obtained by directing a transmitter and receiver toward the wind driven surface of a freshwater lake. Data for the known signal consist of echoes from a styrofoam sphere. Both signal...
Topics: DTIC Archive, Estes,Arthur J, TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS, *SONAR SOUND ANALYZERS,...
Results investigating the effects of variable bottom composition on modeled high-frequency backscattered levels are presented for a typical shallow-water, variable bottom (range-dependent) environment. The modeled environment consisted of a single sound speed profile, a flat sea bottom with range-dependent bottom composition, and a smooth, flat sea surface. Coarse-and fine-grained sandy areas were partitioned in range to create range dependence. Bottom backscattering and reflection loss for...
Topics: DTIC Archive, Savage, Kristen D., NAVAL RESEARCH LAB STENNIS SPACE CENTER MS, *ACOUSTIC SCATTERING,...
The objectives of this study were to enhance understanding of the parameters affecting transmission loss in the shallow waters of the Timor Sea and to conduct a performance analysis of the range dependent acoustic PE model, RAM. The study utilized transmission loss data (from 10-1600 Hz) collected by DSTO and NAWC during the SWISS 1 experiment held in the Sahul Shelf area in early March 1994 in waters ranging from 60 to 120 m depth. In addition, transmission loss data from a similar experiment...
Topics: DTIC Archive, Taylor, Stuart M., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *SOUND TRANSMISSION,...
This document is a compendium of simulation models for use in a wide variety of research and development projects. The purpose of this compilation is to acquaint the reader with the functional capability of each of the models, and to explain how the models are employed in simulating a physical system.
Topics: DTIC Archive, TRACOR INC AUSTIN TEX, *ACOUSTIC DETECTION, *TRANSDUCERS, *SONAR, *ECHO RANGING,...
588
588
Jun 9, 2011
06/11
by
Litvin, Faydor L.; Fuentes, Alfonso; Vecchiato, Daniele; Gonzalez-Perez, Ignaci
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The development of new types of planetary and planetary face-gear drives is proposed. The new designs are based on regulating backlash between the gears and modifying the tooth surfaces to improve the design. The goal of this work is to obtain a nearly uniform distribution of load between the planet gears. In addition, a new type of planetary face-gear drive was developed in this project.
Topics: FUEL TANKS, PASSENGERS, TRANSMITTERS, ELECTROMAGNETIC FIELDS, FAULT DETECTION, PORTABLE EQUIPMENT,...
Loading effects of aircraft seats in an electromagnetic reverberating environment are investigated. The effects are determined by comparing the reverberation chamber s insertion losses with and without the seats. The average per-seat absorption cross-sections are derived for coach and first class seats, and the results are compared for several seat configurations. An example is given for how the seat absorption cross-sections can be used to estimate the loading effects on the RF environment in...
Topics: NASA Technical Reports Server (NTRS), RADIO FREQUENCIES, REVERBERATION CHAMBERS, SEATS, LOADS...
Bell System Technical Journal, 12: 1. January 1933 pp 119-122. Abstracts of Technical Articles from Bell System Sources.
Topics: reverberation, system, bell, telephone, storage, cable, humidities, adsorption, resistances, air,...
Topics: DTIC Archive, MAURY CENTER FOR OCEAN SCIENCE WASHINGTON DC, *ANTISUBMARINE WARFARE, *UNDERWATER...
This report discusses high frequency (15-60 kHz) models of surface forward scattering and reflection that are appropriate for use in acoustic simulations based on ray tracing techniques. Typically, some of the following properties of a pulse after a single surface interaction are needed for modeling purposes: (1) the amplitude as a function of time in or near the specular direction (for example, this gives pulse elongation); (2) the corresponding amplitude statistics; (3) the partitioning into...
Topics: DTIC Archive, Thorsos,E I, WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB, *ACOUSTIC SCATTERING,...
The long-term goal of this research is to develop a package of upgraded bottom reverberation codes based on up-to-date understanding of the physics and mechanisms of sound-seabed interaction. The specific scientific objective of this project is to develop a prototype for a package of physics-based bottom reverberation codes which would be self-consistent and practical. It assumes that the codes would be tested by practical use, particularly by including in analysis of existing seabed scattering...
Topics: DTIC Archive, Ivakin, Anatoliy N, WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB, *SHALLOW WATER,...
The long-term goal is adaptive environmentally aware active sonar design and performance enhancement in shallow water through a better understanding of bottom reverberation, which is a major source of active sonar interference.
Topics: DTIC Archive, BBN TECHNOLOGIES CAMBRIDGE MA, *REVERBERATION, *SHALLOW WATER, *SONAR, MODELS
UNITES is a unique, interdisciplinary team with expertise spanning the environment (physical oceanography and bottom geology), ocean acoustics (propagation, ambient noise, reverberation and signal processing), and tactical sonar systems. The overall goals of the research are to enhance the understanding of the uncertainty in the ocean environment (including the sea bottom), characterize its impact on sonar system performance, and provide the Navy with guidance for understanding sonar system...
Topics: DTIC Archive, OCEAN ACOUSTICAL SERVICES AND INSTRUMENTATION SYSTEMS INC LEXINGTON MA, *OCEAN...
UNITES is a unique, interdisciplinary team with expertise spanning the environment (physical oceanography and bottom geology), ocean acoustics (propagation, ambient noise, reverberation and signal processing), and tactical sonar systems. The overall goals of the research are to enhance the understanding of the uncertainty in the ocean environment (including the sea bottom), characterize its impact on sonar system performance, and provide the Navy with guidance for understanding sonar system...
Topics: DTIC Archive, OCEAN ACOUSTICAL SERVICES AND INSTRUMENTATION SYSTEMS INC LEXINGTON MA, *OCEAN...
The first section describes the observations of first-order mantle reverberations and develops techniques for using these data to constrain upper-mantle velocity and attenuation structure. The second section discusses our work on the waveform inversion of higher-mode surface waves, and the third analyzes the resolving power of the higher-mode data set. The fourth section reviews recent progress in seismic tomography and its implications for mantle dynamics. The fifth section applies methods for...
Topics: DTIC Archive, Jordan,Thomas H, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF EARTH ATMOSPHERIC AND...
Sound scattering from rough surfaces is a very complex phenomenon. Although it has been studied extensively, a full understanding of a three-dimensional scattering function is still lacking. In 1989 the Office of Naval Research (ONR) established the Acoustic Reverberation Special Research Program (ARSRP) whose purpose is to improve this understanding for scattering from the sea surface and the seafloor. As a part of the bottom scattering effort of the ARSRP, researchers from NRL, several...
Topics: DTIC Archive, Caruthers, Jerald W., NAVAL RESEARCH LAB STENNIS SPACE CENTER MS, *ACOUSTIC...
The Third Acoustic Surface Reverberation Experiment (ASREX III) took place from December 1993 to March 1994 in the mid-Atlantic. As part of this experiment, two moorings were deployed to measure the environmental background. A meteorological and oceanographic mooring was deployed to characterize the surface wind stress, buoyancy flux, and the current and temperature structure over the top 500 meters. A Seatex WavescanTM buoy was deployed to characterize the directional wave spectrum. This...
Topics: DTIC Archive, Galbraith, Nancy R., WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *METEOROLOGICAL DATA,...
The work reported here is taken verbatim from a proposal for the study and design of a computer aided sonar echo classification system. In the proposal, the discussion of a signal processing and waveform design was felt to be of sufficient general nature to be useful to others working in related fields.
Topics: DTIC Archive, Applebaum,Sid, GENERAL ELECTRIC CO SYRACUSE N Y HEAVY MILITARY ELECTRONIC SYSTEMS,...
The CST (Critical Sea Test) Support project is a two-year effort that addresses further development of the SAIC Active System Model (NOP Baseline) for at-sea modeling support. This report covers the first installment of this model development. Efforts during this phase primarily have been directed to reconfiguring the graphics portion of the model in order to provide more flexible graphical display of the computed arrays and to allow graphical output of the environmental data bases. A second...
Topics: DTIC Archive, Eller, A, SCIENCE APPLICATIONS INTERNATIONAL CORP MCLEAN VA, *OCEANOGRAPHY, *PHYSICAL...
The purpose of this thesis was to investigate a shallow coastal region to compile a detailed environmental picture of its sediment composition and water characteristics and from this model MCM sonar performance at the FBE-H exercise location as a means to determine what parameters exerted the greatest effect on performance. Seven parameters were intercompared to assess their sensitivity in detecting mines: bottom type, SSP, water depth/sonar depth, mine depth, frequency, sonars and models....
Topics: DTIC Archive, Dubsky, Barbra K, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *MINE COUNTERMEASURES,...
A better understanding of the science and engineering of buried mine detection leading to safe, standoff detection technologies. A unified model of acoustic penetration of ocean sediments for a wide variety of sediment types, from gravel through sand, silt and clay and combinations thereof, and a model of signal attenuation and reverberation due to multiple scattering by sediment grains.
Topics: DTIC Archive, TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS, *BURIED OBJECTS, *UNDERWATER MINES, *MINE...
LONG-TERM GOALS: Propagation and reverberation of acoustic fields in shallow waters depend strongly on the spatial variability of seabed geoacoustic parameters, and lack of knowledge of seabed variability is often a limiting factor in acoustic modeling applications. However, direct sampling (e.g., coring) of vertical and lateral variability is expensive and laborious, and matched-field and other long-range inversion methods fail to provide sufficient resolution. The long-term goal of this work...
Topics: DTIC Archive, VICTORIA UNIV (BRITISH COLUMBIA) SCHOOL OF EARTH AND OCEAN SCIENCES, *GEOACOUSTICS,...
This report describes a computer cataloging technique that is capable of detecting strong signals. It was developed for use in analyzing the unprocessed but digitized signal data obtained in the joint US/UK VERULAM/ANDREW sea trials. Using the technique of energy averaging, the time of the peak arrival of one way signals and bottom reflections are detected and recorded.
Topics: DTIC Archive, Mueller,R A, TRACOR INC SAN DIEGO CA SAN DIEGO LAB, *SONAR SIGNALS, SIGNAL...
A computer program, Navy Interim Surface ship Model (NISSM) II, has been developed to predict the performance of active sonar systems. Thereby acoustic ray trajectories, propagation-loss curves, boundary and volume reverberation, signal-to-noise ratios, and the probability of detection are determined using continuous-gradient ray-tracing techniques. Caustic, shadow zone, and surface-duct corrections modify the classical ray theory. The major limitations of the model are that the ocean bottom...
Topics: DTIC Archive, Weinberg, Henry, NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT, *COMPUTER PROGRAMS,...
The goal of this research was to make a performance assessment for a generic UK Low Frequency Active Sonar (LFAS) operating in the northwest approaches to the UK. Five diverse and operationally significant sound speed and geoacoustic transects of the region in winter and summer were considered. The intention was to use an operational, ray theory based, acoustic propagation loss model for the performance assessment at 400 Hz and. 800 Hz for various source/target depths. Prior to the assessment...
Topics: DTIC Archive, Hunt, Charles J., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *GEOACOUSTICS, *SONAR,...
R&D Report 1956-27 : Visit to U.S.A. and Canada - June 1956. T. Somerville The Second International Congress on Acoustics was attended at Cambridge, Massachusetts, and following this visits were paid to broadcasting organisations and laboratories engaged on acoustic research to USA. A visit was also paid to the Canadian Broadcasting Corporation.
Topics: reverberation, sound, acoustics, studios, loudspeakers, reflections, acoustic, noise, broadcasting,...
R&D Report 1966-11 : Acoustic tests in Dubbing Suite 1, East Block, Television Centre. D.K. Jones The installation of a new Dubbing Theatre and its associated Mixer and Recording Rooms has recently been completed in the East Block at Television Centre. Reverberation times and noise levels were measured in the three rooms and the sound insulation between the rooms taken in pairs was obtained. The results are given in Section 2, and their implications are discussed in Section 3.
Topics: reverberation, mixer, insulation, recording, noise, rooms, theatre, dubbing, sound, room,...
15
15
Aug 5, 2020
08/20
by
Elijah Harter
movies
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Ah yes, F U N N Y R E V E R B.
Topics: reverb, reverb marketplace, crazy reverb, funny, cool reverb, gated reverb, spring reverb, funny...
NRL is developing a long range active acoustics technique for estimating seamount heights and mapping undersea topography over an entire ocean basin region. A concept demonstration, the BHST, was conducted in the eastern Atlantic in 1980. The technique uses explosive shot acoustic sources and a large aperture, towed acoustic receiver array. Reverberation data are output to an imaging system to study the spatial distribution of acoustic backscatter. These images are in the form of...
Topics: DTIC Archive, Erskine, F T, NAVAL RESEARCH LAB WASHINGTON DC, *ACOUSTIC SCATTERING, *BATHYMETRY,...
Three popular numerical techniques are employed to examine the acoustic pressure and intensity features present in several environments of interest. Free field propagation and analytically tractable planar interfacial two-fluid transmission and reflection are used to benchmark the commercial software package COMSOL. Canonical Pekeris-type waveguides are used as initial points of comparison to illustrate COMSOL's ability to capture all pertinent physics. Additional environments with non-trivial...
Topics: wave propagation, normal modes, parabolic equation, finite element method, acoustic intensity,...
Several tools have been developed, primarily using MATLAB, for modeling the active return of a target in an arbitrary, three-dimensional ocean environment and for quantifying the environmental distortion and interference. An acoustic model based on ray theory is used to compute the target echo and reverberation. These tools have been applied to Barents Sea and Gulf of Sidra ocean environments for a billboard transmit/receive any of 23 equally spaced elements. The frequency dependence of a sonar...
Topics: DTIC Archive, Huelsnitz, Warren G., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *UNDERSEA WARFARE,...
R&D Report 1971-01 : Simultaneous subliminal signalling in conventional sound circuits: a feasibility study P.C.J. Hill Abstract Programme transmission networks use auxiliary lines for operational control. Considerable savings might be possible if the auxiliary signals could be combined with the associated sound signal and sent simultaneously on a single circuit. The simultaneous system should operate in-band and provide sufficient information for operational use. Ideally, it should be...
Topics: signalling, signal, subjective, frequency, programme, signals, subliminal, sound, notches, khz,...
R&D Report 1975-35 : Acoustic scaling: The design of a large music studio for Manchester. Final report. H.D. Harwood, K.E. Randall, K.F.L. Lansdowne This report gives the results of further modifications to the design of the large music studio for Manchester and assesses their performances subjectively and objectively. Final recommendations for the design are given and these should not only result in a better design than the original, but in a lower cost.
Topics: reverberation, acoustic, studio, observers, standard, optimum, sound, design, music, quality, final...
The problem which Lord Rayleigh considered, (Reflection from a Corrugated Surface) and which several have treated approximately in recent years, is developed in a general form. An exact solution is obtained by extensive use of Wiener's Generalized Harmonic Analysis. This solution is readily extended to include electromagnetic waves, general elastic waves, and non-planar, non-harmonic sources. Numerical evaluation of the formulae is considered by means of an operational representation, from...
Topics: DTIC Archive, Marsh,H W, NAVY UNDERWATER SOUND LAB NEW LONDON CT, *ACOUSTIC SCATTERING, *UNDERWATER...
From an operational perspective clutter is one of the most important problems facing active sonar in shallow water. The long-term objective of this work is, through quantitative model-data comparisons, to better understand target echo, clutter and reverberation in shallow water environments, and to develop techniques and models for multistatic sonar, rapid environmental assessment and environmentally adaptive sonar.
Topics: DTIC Archive, Ellis,Dale D, Mount Allison University Sackville, NB Canada, sea clutter, shallow...
The long-term goal of this research is development of computationally efficient physics-based methods for modeling of propagation, scattering, and reverberation in shallow waters with complicated spatial and temporal variability of environmental parameters. Scientific objective of this project is to develop a model of mid frequency reverberation for very shallow water environments. The model is to be relevant to specific conditions (1 10 kHz, 20 m water depth, 5 km range) of the ONR Target and...
Topics: DTIC Archive, WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB, *MEDIUM FREQUENCY, *REVERBERATION,...
There is a unique relationship between sound wave scattering from a rough surface and its elevation spectrum. This relationship allows the use of available underwater sound reverberation measurements in the wave number range 0.025 to 2.5 radians/cm (5 to 55 radians/sec) to be used to develop sea surface capillary wave spectra. As an aside, optically measured surface slope spectra are converted to elevation spectra and these suggest the possible variability of capillary wave height spectra as...
Topics: DTIC Archive, INSTITUTE FOR DEFENSE ANALYSES ALEXANDRIA VA, *ACOUSTIC SCATTERING, *SOUND WAVES,...
A previous contract resulted in the addition of the ray theory program Bellhop to the reverberation inversion program BREVER. This was done to allow inversion of reverberation results calculated from acoustic data recorded during the BASE 04 trials. However tests with Bellhop using parameters from the BASE 04 site indicated shortcomings in that program. The current contract began with test runs of CASS, a potential Bellhop replacement for reverberation inversions. The test results indicated...
Topics: DTIC Archive, Calnan, C, DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA),...
The objectives of this research are: a) to develop the method of extracting the modal back-scattering matrix Smn from the reverberation data in shallow-water, b) to analysis the adiabaticity of acoustic propagation in shallow-water so we can identify the conditions that the modal back-scattering matrix is induced by bottom-interaction only, and the volum-interaction is not involved.
Topics: DTIC Archive, SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB, *REVERBERATION,...
An expression is developed based upon the ray-wave synthesis generalization of the Kirchoff-Helmholtz acoustic field equation. This expression represents the signal received for the case of an arbitrary narrow band transmission, moving transmitter and receiver, arbitrary transmit and receive beam patterns, a smoothly varying sound speed profile and includes scattering from a rough bottom. The mean and correlation functions of this field are computed and used to calculate the generalized...
Topics: DTIC Archive, Grace, O D, NAVAL UNDERSEA CENTER SAN DIEGO CA, *ACOUSTIC SIGNALS, *OCEAN BOTTOM,...
This technical report summarizes work done during the period December 1979 - May 1980 on the computation of relative receiver functions. Such functions are vitally important to the understanding of explosion or earthquake source functions, since the effects of crustal reverberations, local amplification effects and lateral variations in attenuation near seismic stations cannot otherwise be separated from source or source crustal properties. Two steps are involved in the calculation. Trace...
Topics: DTIC Archive, Lundquist, G M, SIERRA GEOPHYSICS INC ARCADIA CA, *RECURSIVE FUNCTIONS,...
Measurements of backscattering from the ocean bottom were performed in a shallow water environment off the coast of Oregon as part of the Littoral Warfare Advanced Development 99-3 Experiment. Scattering strengths were obtained at 0.4 to 4.5 kHz as a function of the mean grazing angle. For all measurements, the grazing angle dependence was fit adequately by assuming a dependence of scattering strength (dB) on the sine of the mean grazing angle: mu + 10 log (sin theta). At the primary scattering...
Topics: DTIC Archive, Kunz, Edward L, NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS SYSTEMS BRANCH,...
The purpose of this document is to provide a review and synthesis of the author's recent detailed analyses of scatter channels and target models for the active threshold detection of underwater targets in an ocean environment [1]. The summary and synthesis describe the main results of analytic modeling of: (1) Generalized scatter (reverberation) channels; (2) Line target models, with bistatic orientation and doppler; (3) Threshold detection algorithms for the mixed gauss, non-gauss ambient and...
Topics: DTIC Archive, NAVAL UNDERSEA WARFARE CENTER NEWPORT DIV NEW LONDON CT NEW LONDON DETACHMENT,...
Acoustic clutter is the primary problem encountered by active sonar systems operating in Continental Shelf environments. Clutter is defined as any returns from the environment that stand prominently above the diffuse and temporally decaying reverberation background and so can be confused with or camouflage returns from an intended target such as an underwater vehicle. The long-term goal of this program is to determine and understand the physical mechanisms that cause acoustic clutter in...
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING, *ACOUSTIC SCATTERING,...
