We received a question from a consumer regarding low-frequency home and vibration. After a response from expert staff of Acoustics and Noise instructors and a few additional posts on this general topic of interest, the response below came from the original consumer. Dear Sir, Here is my reply. You asked for it, and it is […]
We received a question from a consumer regarding low-frequency home and vibration. After a response from expert staff of Acoustics and Noise instructors and a few additional posts on this general topic of interest, the response below came from the original consumer.
Here is my reply. You asked for it, and it is lengthy. I am so grateful that you all are taking your time to give me your suggestions. I think a probable low frequency noise source, in addition to the trains, and obvious manufacturers’ noises, could be an asphalt batch plant that is located just behind our neighborhood. I drove by and listened and it is quite noisy with its clattering conveyer belts, giant blower, and the huge rotating mixing bin. I doubt we could have any influence on quieting such an operation. When we moved into our present house this plant was hidden by trees. Now that the leaves are gone, it is easily seen. Let the renter beware!
We have tried all the things that were suggested in your e-mail. White noise machines and fans just added noise to the home and was not the solution I needed. The best brand of ear plugs worked well, but are kind of dangerous when you need to listen to what is going on in the house at night….like when someone might be sick and need help. ( mothers can appreciate this reason), or a tornado siren, etc. My husband must sleep and so I have the “night watch”. .The Bose headphones (thanks Grandma) did not do a thing for the low frequency, but one of my sons is enjoying them tremendously now for listening to music. I hate that she wasted so much money on something that didn’t work. I, too, have wasted lots of money buying several bundles of Fibrex to use as “bass traps” of sorts thinking that it might help. It did not.
We did the realtor thing also. We moved from our first house recently. That house has its own story. We had moved to this town from out of state and did not know much about the area. Well, the house we bought was down the street from a gas well compressor. It was hidden in a wooded area and we did not know about it. Who would ever think that such a thing as a gas well compressor would be in a neighborhood…..only in Texas. The days we viewed the house happened to be some of the few days a year that the compressor was down for repairs or maintenance. On closing day when I walked up the stairs to turn the key in the door, I said to my self, “What is that noise.” After searching the neighborhood, we discovered the culprit to be a very old noisy natural gas driven compressor on a gas well. I fought that oil company for a long time and only was successful getting them to put up a wooden fence that did absolutely no good. Oil companies are King around here. They always expressed to me that they were compliant. They were, but this city has wimpy standards and codes that do not measure low frequency. We had spent lots of time, sweat, tears and money fixing up “this old house” and we did not want to move. We had redone the wooden floors ourselves, and I did not want to cover them up with carpet, even though that might have helped with the sound. We couldn’t afford to change out the old windows that were huge and had just been refurbished by me. Our home was built in an L shape facing the compressor. This was perfect for capturing the “waves”. They came right in through our large glass windows. In addition to that, there were metal awnings over each window acting like ears to reflect the sound in through the single pane windows. (I had refurbished those as well) The neighborhood was refreshingly quiet on the few days that “The Beast” was off for one reason or another.
After three years of torment, the for sale sign went up. We disclosed the noise ( which probably brought our home value down) to the new buyer. She was not home much of the time anyway so she was not as bothered by it. The search for a quieter place was on. We were scared to think of buying again without knowing if “the sound” would be in that area too. , “ I had gone to look at houses for sale, just to see if I could hear how the house “sounded” and just to “test” a neighborhood. We decided just to rent. Little did we know that rental homes that are large enough for our family of six and that are in our price range are extremely hard to find in our town. We ended up having to grab a house when it became available just to get a decent place to live. As it turns out, we ended up moving from one frying pan to another frying pan so to speak. We have now been living in this rental for ten months and we are still plagued with noise problems. I say we because even though the others of our household are not as sensitive to LFN as I am, they still have to live with someone (the mom) who is and whose daily life is not as efficient as it could be were I able to sufficiently rest and relax. I went with our church on a mission trip to Mexico a couple of years ago. While up in a quiet mountain village, I discovered how wonderful peace and quiet were, and I realized just how much that LFN affected me while living in our bombarded home.
Since we now rent, I can’t beef up the windows, but I have heard that double panes do not help with low frequency anyway. I’ll try to make a window plug to see if that helps. I can’t run the TV “off channel” because we need to concentrate and study at home. We are one of those homeschooling families. Also, that noise is annoying to my teenage daughter and me.
You asked about whether or not other neighbors have had the same problems as I. I can’t tell you that. We haven’t gotten to know our neighbors very well yet. There are some factors to remember when questioning the neighbors about noise problems. Many in our neighborhood are retired and wearing hearing aids. They, of course, do not have problems with the noise. Second, if they did hear the offending frequency, they would be hesitant to say so in fear that this information might be something that could “go public” and cause their home values to go down. Third, low frequency noise is most often a source of annoyance to those fifty and older (I give away my age). The younger ones in the neighborhood have not yet reached that point. On a side note, there is an old man in the neighborhood who sits out in his attached garage with the garage door up for many hours a day. He will even sit out there when it is 100 degrees outside. I am just curious if he has a problem with LFN and is trying to escape it as I am. By the way, when I am out working in my ten by twelve foot shed (made of that composite siding stuff and sitting on wooden skids) I can’t hear or feel the vibration. This makes me wonder if the noise could be possibly ground borne. The LFN does seem to be worse when it is raining…..hum….saturated soil conducts noise very well doesn’t it. If the LFN was ground borne, would ….putting down a wood or laminate flooring that had a good coating of Green Glue behind it help. Is there any conclusive way to determine if LFN is indeed coming through a concrete slab? (I know this is some of that thousands of dollars of advice coming my way.) As was suggested, I am going to try to decouple the bed from the floor. I’ll order some sheets of sorbothane for that purpose. They are supposed to work better than rubber. What kind of instrument would measure the wall or slab vibrations?
My son, who is now an engineering major (ME), once measured the sound with a microphone on his computer. Using music recording software, he measured the frequencies from 30 to 60htz or so. He had fun isolating the sound and turning it way up for all to hear and feel till we yelled at him to shut it off….ah teens. He captured it in the tile shower. So I know it is “out there” and not just “in my head”. It could be that I am one of those “hummers”. Read about them online. They can hear the Kokomo Hum, the Taos Hum, the London Hum, etc. There is even a low frequency sufferer’s society. This is your market for whoever invents a comfortable low frequency blocking head gear that can be worn at night. This wouldn’t block (as ear plugs do) the types of noise that parent’s need to hear at night.
I would be interested in any tests like the one that one of the teacher’s mentioned ….measuring the frequency outdoors and comparing it to the indoor reading. I guess I just have to rent a device that measures what I need to measure. We would like to move, but as I said previously, I would not like to buy a home without knowing that I can block the offending noise that this town seems to produce whether from trains, underground gas pipes, well drilling, or chemical and manufacturing industries, etc. If we were to rent, we could not spend lots of money to “treat” the house for LFN. My husband likes his job and would like to stay in the area if possible. Me, I’d rather move to a small mountain village in Mexico. Or until then, I’ll just sleep with a pair of sorbothane shoe insoles smashed over my ears.
I am glad you are teaching classes to train engineers in ways of mitigating noise and vibration, because ultimately these problems have a personal side and a personal face. If I have been a “textbook” case for you then so be it, and may you all become the best problem solvers in this area. If any of you have any other suggestions for me, send them my way. If you solve my problem, then my hat is (or should I say ear plugs are) off to you. Please do not share my e-mail address with the masses.
My humble thanks,
Miami Herald September 10, 2009 By Curtis Morgan Every winter endangered North Atlantic right whales migrate to warm, shallow waters to give birth and nurse their young. That’s right next to where the U.S. Navy wants to conduct antisubmarine training. Florida isn’t known for whale watching, but every winter the coastline offers a haven for […]
September 10, 2009
By Curtis Morgan
Every winter endangered North Atlantic right whales migrate to warm, shallow waters to give birth and nurse their young.
That’s right next to where the U.S. Navy wants to conduct antisubmarine training.
Florida isn’t known for whale watching, but every winter the coastline offers a haven for endangered North Atlantic right whales. They migrate to warm, shallow waters to give birth and nurse little — relatively speaking — one-ton bundles of blubber.
That’s right next to where the U.S. Navy wants to conduct antisubmarine training.
The Navy has selected a site bordering a federally protected whale nursery stretching from Savannah to Sebastian for an undersea warfare range, where ships, submarines and aircraft outfitted with powerful sonar can practice hunting subs.
Citing voluminous studies, the Navy concluded that training 58 miles off Jacksonville would rarely, and barely, disturb right whales.
Environmentalists say the Navy has soft-pedaled risks from the 500-square-mile range.
Ship strikes already rank as the top right whale killer. The Navy also intends to heavily employ sonar that can disrupt feeding and communication, cause hearing damage and — in extreme cases — trigger mass strandings such as one in the Bahamas that killed six beaked whales in 2000.
“It’s one of the worst possible places,” said Catherine Wannamaker, an attorney for the Southern Environmental Law Center, one of 21 groups that contested the choice. “It’s right next to the calving grounds for one of the rarest whales in the world.”
The groups contend that the range poses a disruptive, potentially deadly threat to a whale population numbering no more than 400 — and that’s after producing 39 calves last year, the most in decades. Florida and Georgia environmental regulators have raised similar concerns.
Navy is moving ahead because Florida’s location and logistics beat sites off South Carolina, North Carolina and Maryland. Jacksonville boasts a seaport, air base and submarine base across the St. Mary’s River in King’s Bay, Ga.
The Navy already has a deep-water sonar range in the Bahamas, but Julie Ripley, the Navy’s environmental spokeswoman, said the shallow sea floor and busy shipping lanes off northeast Florida provide a real-world test for sonar operators who must pinpoint a new generation of stealthier subs.
Environmentalists, who have been battling the Navy for years over sonar, argue that it’s the whales that are perishable.
Though there are signs of slow recovery, scientists consider their future precarious. The whales take a decade to hit sexual maturity. Females produce one calf a year, so losing one prematurely can set back recovery.
Ship strikes are such a serious concern — 22 whales were hit between 1999 and 2006, with 13 confirmed deaths — that the fisheries service last year imposed seasonal zones limiting large vessels to 10 knots in whale habitat.
The Navy — involved in roughly one-sixth of 134 documented strikes over 60 years — was exempted.
Factoring in total sea hours, the service calculated the chance of any Navy ship hitting a whale in any year at .0000472 percent. The chances of not doing it: 99.99 percent.
While whales have been spotted 60 miles out where the range is planned, past surveys — which environmentalists consider inadequate — suggest that most swim relatively close to shore, some 30 miles from where the Navy plans to train.
The Navy, which adopted whale-avoidance policies in 2002, also has proposed more precautions during calving season — posted lookouts, daytime training and exercising “extreme caution” in ship speed and sonar power.
But environmentalists remain skeptical, pointing to a series of strikes that have killed whales since 2000, including six pregnant females.
Then there is the complex question of sonar. For the Navy, it’s critical protection for military vessels and shipping lanes — particularly mid-frequency active systems that emit “pings” of powerful sound, measuring echoes to identify and track targets.
There is no dispute that active sonar can disturb whales and dolphins. They rely on echolocation, their own internal sonar, to navigate and hunt, and use an array of calls or “songs” to communicate.
But research — much of it bankrolled by $20 million a year from the Navy — shows widely varying impacts, depending on species and sonar levels.
Animals can leave an area, possibly under stress, or abandon feeding or breeding. Some studies indicate that repeated exposure can cause temporary hearing loss. In the worst cases, fleeing whales and dolphins beach in mass, often fatal, strandings.
The Navy, in a 2001 study after 17 whales and a dolphin beached in the Bahamas, acknowledged that its mid-frequency sonar played a role, but also pointed to an unusual confluence of other factors.
Necropsies of whales that beached in the Canary Islands in 2002 during international naval exercises showed brain hemorrhages, vascular ruptures and lung congestion. One theory is that they bolt from depths so quickly their organs can’t handle rapid pressure changes — akin to the “bends,” or embolisms that divers suffer when surfacing too quickly.
As a concession to state concerns, the Navy agreed not to lay fiber-optic cable and transducers during calving season, which runs from mid-November to mid-April.
Wannamaker said it would resolve many concerns if the Navy made the same pledge for sonar training. The Navy responded that option has “been given consideration” but that they want to retain “flexibility.”
Wannamaker said the groups are pondering a lawsuit, not trusting that more studies and surveys will sway the final decision.
“Once you build a $100 million project,” she said, “nobody is going to tell them they can’t use it.” Full story here.
Lowrance announced today the premier of its next-generation sonar technology, the LSS-1 StructureScan(TM) sonar imaging module for Lowrance High Definition Systems (HDS), at ICAST 2009 in Orlando, Florida. Raising the bar in fish-finding technology, the sonar-imaging module is the world’s first to offer anglers a new dimension in underwater picture-like displays – side-to-side plus straight […]
Lowrance announced today the premier of its next-generation sonar technology, the LSS-1 StructureScan(TM) sonar imaging module for Lowrance High Definition Systems (HDS), at ICAST 2009 in Orlando, Florida. Raising the bar in fish-finding technology, the sonar-imaging module is the world’s first to offer anglers a new dimension in underwater picture-like displays – side-to-side plus straight down, full panoramic viewing.
The innovative Lowrance StructureScan features a combination of SideScan and an exclusive new DownScan Imaging(TM) technology. SideScan provides full-screen left and right side-viewing with extra-crisp detail of up to 480 ft. (146 m) of underwater coverage that displays structure and fish targets, as well as their imaging-scan shadows. The new DownScan Imaging feature allows anglers, for the first time, to see submerged detail directly beneath their boats, providing a complete underwater picture in a screen format that is easy to interpret. With revolutionary on-screen display versatility, anglers can merge Lowrance side and down sonar scans in split-screen to view wide-area surveys and highly-defined detail. As a unique new tool, anglers can also compare DownScan Imaging with 2D sonar images in split-screen display to better distinguish fish from structure. Removing all of the guesswork common to existing fish-finding technology, the new LSS-1 delivers the highest underwater definition ever achieved with crystal-clear views in shallow and deep, freshwater or saltwater – even at speeds up to 30 mph.
Scientists on board a federal fisheries research vassal in Alaska’s Pribilof Islands are using multi-beam sonar to survey and map seafloors. According to ecologists, mapping this vital crab habitat is an important step in preserving deteriorating king crab populations. The primary goal of current mapping pilot project is to test the usefulness of multi-beam sonar […]
Scientists on board a federal fisheries research vassal in Alaska’s Pribilof Islands are using multi-beam sonar to survey and map seafloors. According to ecologists, mapping this vital crab habitat is an important step in preserving deteriorating king crab populations.
The primary goal of current mapping pilot project is to test the usefulness of multi-beam sonar systems for finding “shell hash” (deposits of crushed crab shell believed to be important in the survival of young crabs). In the past efforts to monitor, crab populations and record vital habitats were limited to trawl and pot surveys.
Although these surveys could inform ecologist which habitats were being used as nursery grounds for immature crabs they could not provide much needed information regarding the habitat itself. Today’s current multi-beam sonar technology has the potential to drastically transform ecologist’s ability to monitor and preserve critical habitats of declining sea species. These technologies, however, do not come without a cost. According to Michelle Ridgway, the ecologist in charge of the shell hash project the systems currently being tested cost over $3,000 an hour to operate.
After the initial data is, collected Ridgway will compare the newly collected sonar imagery to seafloor samples, side scan sonar imagery, and remotely operated vehicle video that have already been collected to help interpret the acoustic backscatter images.
Classic Acoustics and Sonar books for from Peninsula Publishing Los Altos Hills, California USA Many of these texts were written by current or retired ATIcourse instructors and several of the textbooks are given out free as part of the ATI sponsored short course on the subject. June 2009 Principles of Underwater Sound, Third edition. Robert […]
Classic Acoustics and Sonar books for from Peninsula Publishing Los Altos Hills, California USA
Many of these texts were written by current or retired ATIcourse instructors and several of the textbooks are given out free as part of the ATI sponsored short course on the subject.
Principles of Underwater Sound, Third edition. Robert J. Urick. The most widely used book on underwater acoustics and sonar published today. This book continues to be the standby of practicing engineers, scientists, underwater systems managers and students. Its contents lie squarely in the middle between theory at one end and practical technology at the other. Principles summarizes fundamentals, effects and phenomena of underwater sound and their application to sonar. It provides numerical, quantitative data for the solution of practical problems. 229 figures; 23 tables; 673 references. Detailed index pinpoints data and explanations instantly. Problem section with solutions.
Hardcover. 444 pages. ISBN: 9780932146625
Mechanics of Underwater Noise. Donald Ross. Most authoritative book on fundamentals of underwater noise radiated by ships, submarines, torpedoes. Stresses physical explanations of mechanisms by which noise is generated, transmitted by structures and radiated into the sea.
Hardcover. 375 pages. ISBN: 9780932146168
Sediment Acoustics. Robert D. Stoll. Seminal book addressing Biot Theory for the modeling of acoustic behavior of ocean sediments. Written for seismic-acousticians in the geo-exploration, engineering, oceanographic and underwater sound communities. Stoll, a respected leader in marine geoacoustics for more than forty years, added a brief preface and updated selected bibliography to this second printing of his book, first published in 1989. Sediment Acoustics provides an excellent introduction to Biot Theory, the physics underlying the model parameters, and experimentally measurable predictions of the theory. The book constitutes a major synthesis for non-specialists: the results of laboratory, in-situ and numerical modeling studies of seismic-acoustic wave propagation, reflection and attenuation in two-phase poro-visco-elastic media. Includes tutorial sections and references for new researchers in seismic modeling, quantitative seismic stratigraphy, offshore marine geotechnique, underwater acoustics and sonar, and ground-interacting aeroacoustics.
Softcover. 172 pages. ISBN: 9780932146144
Underwater Electroacoustic Transducers. Dennis Stansfield. This reprint is a practical handbook for users and designers of underwater transducers. It has been an authoritative text in the field since first published by the Bath University Press in 1991. Design methods are illustrated by concentrating on the design of piezoelectric transducers in the 2 – 20 kHz range, most commonly used in sonar systems. Designs for frequencies below this range are also discussed. Treatment is down-to-earth and avoids complex mathematics. Topics include the role of the transducer as an element of the complete system; wide bandwidth, high power transmitter applications; wide band hydrophones; characteristics of piezoelectric and magnetostrictive materials; and transducer testing. For the user, the wide range of topics and practical approach of the book help him to identify the most important features of the requirement and assist him in drawing up realistic specifications. For the designer, the book describes the necessary theoretical and practical aspects involved in developing a transducer to most effectively suit the application and it discusses the main features of the various types of designs.
Softcover. 429 pages. ISBN: 9780932146724
Introduction to the Theory and Design of Sonar Transducers. Oscar Bryan Wilson. Written in 1985 as a text at the Naval Postgraduate School, this book provides a complete treatment of the fundamentals of transducer theory and design using equivalent circuit techniques. Subjects addressed: introductory baseline and definitions, equivalent circuits, properties of materials: piezoelectric and magnetorestrictive, hydrophone design and transducer arrays.
Hardcover. 202 pages. ISBN: 9780932146229
Underwater Electroacoustic Measurements. Robert J. Bobber. Theory and practice of measuring electroacoustic parameters such as response, sensitivity, directivity, impedance, efficiency, linearity and noise limits of transducers used in sonars.
Hardcover. 341 pages. ISBN: 9780932146199
Matched Field Processing for Underwater Acoustics. Alexandra Tolstoy. Published by the World Scientific Publishing Company in 1993. The author was with the Naval Research Laboratory. Matched Field Processing is the process of cross-correlation of a measured field with a modeled, predicted or replica field to determine a set of input parameters that yield the highest correlation. Typically, input parameters in to a selected sound propagation model would include candidate range, bearing and depth of a source relative to the receiving array. The sound propagation model might be defined by environmental data such as sound speed profiles, bottom and surface conditions, tides, and composition of the water. The matched field processing (MFP) would be employed to determine the location of the source – the exact relative range, bearing and depth of the source. This book is for scientists and engineers who are familiarizing themselves with MFP and those in need of detailed information about the process. The first two chapters address a brief history of MFP and discuss other types of processors used in underwater acoustics. The third chapter discusses where errors in MFP solutions occur due to errors in the propagation model. Chapter 4 gives the reader a familiarity of how linear and minimum variance processors perform under a wide range of conditions. And the last chapter addresses broadband processing, source movement, and multiple sources.
Hardcover. 228 pages. ISBN: 9789810210595
Space-Time Information Processing. Charles Loda and A. Winder. Classic reference for signal processing and data analysis for acoustic and sonar engineering. Features Fourier transforms, statistical analyses, spectra and correlation. Valuable chapters address spatially and temporally limited functions, optimal filtering procedures, and interpretation of results.
Hardcover. 192 pages. ISBN: 9780932146045
Transducers and Arrays for Underwater Sound. Charles H. Sherman and John Butler. This book is published by Springer, released in 2007, and sold by Peninsula Publishing. This is the most recent and complete book on the theory and design of underwater transducers in print today. Sponsored by the Office of Naval Research of the U. S. Navy. This book addresses the theory, development and design of electroacoustic transducers for underwater applications. It is more comprehensive than any existing book in this field. It includes the basics of the six major types of electroacoustic transducers and shows why piezoelectric ceramic transducers are the most suitable for underwater sound. It presents the basic acoustic concepts and models needed in transducer and transducer array development, and discusses most currently used transducer designs. It analyzes nonlinear effects and describes methods of transducer evaluation and measurement. The extensive Appendix and numerous diagrams provide an up to date source for use by students and practicing engineers and scientists.
Hardcover. 630 pages. ISBN: 9780387329406
Underwater Acoustic System Analysis, Second Edition. William S. Burdic. Provides a comprehensive exploration of underwater acoustics, acoustic signal generation, and acoustic signal processing for systems analysts, systems engineers and sonar engineers. This book is a reprint of the second edition published in 1991 and is still a classic text in the field. Updated and expanded in 1991, this edition contains all the valuable information it its earlier text plus a detailed discussion of adaptive processing as applied to spatial filtering. You will also find review sections on Fourier analysis, correlation, random processes and hypothesis testing. Highlights include: generation and propagation of compressional acoustic waves in the ocean; narrow band signatures of surface ships caused by cavitating propeller blades and diesel engine firing; optimization of signal-to-noise ratio and spatial resolution in the presence of multiple signals; ambient noise in the ocean; and examples of system performance.
Softcover. 489 pages. ISBN: 9780932146632
Sonar Engineering Handbook. Harrison T. Loeser. Fundamentals and
engineering formulas dealing with sonar, signal processing, sound transmission, noise generation, vibration control and elastomers. Each formula is briefly explained in an associated paragraph with references provided for detailed follow up.
Softcover. 216 pages. ISBN: 9780932146595
Ambient Noise in the Sea. Robert J. Urick. Examines significant aspects of ambient noise beneath sea’s surface: definition; measurement; sources; variation. Essential for work in sonar systems.
Hardcover. 205 pages. ISBN: 9780932146137
Sound Propagation in the Sea. Robert J. Urick. Overviews underwater sound propagation, multipath, deep sound channel, sea surface reflections scattering, attenuation, absorption, modeling.
Hardcover. 225 pages. ISBN: 9780932146083
Physics of Sound in the Sea. Milestone work on undersea sound propagation resulting from the World War II studies. Discusses transmission loss, target strength and echoes from subs/surface ships, sound transmission through wakes, etc.
Hardcover. 577 pages. ISBN: 9780932146244
Side Scan Sonar Record Interpretation. Charles Mazel. Training manual produced by Klein Associates, Inc., manufacturer of side scan sonars. Applies to interpretation of all commercial side scan sonars. The 144 figures and photographs of actual sonar records depict mine and ship targets, shadows, clutter, noise, wakes and dolphins.
Softcover. 146 pages. ISBN: 9780932146502
Noise Reduction. Edited by Leo L. Beranek. Classic book of fundamentals of noise control and noise reduction for the general engineer. Elementary beginnings leading to the advanced aspects of noise reduction for offices, residences, auditoriums and transportation vehicles. Case histories and abundant references.
Hardcover. 776 pages. ISBN: 9780932146588
Collected Papers on Acoustics. Wallace Clement Sabine, the Father of Architectural Acoustics. Acoustic problems in theater, auditorium, church, classrooms and their solutions. Magnificent sketches and photos. This unabridged volume forms the foundation of modern architectural acoustics.
Hardcover. 304 pages. ISBN: 9780932146601
Signal Detection and Recognition by Human Observers. Edited by John A. Swets in 1964, this book was the first to bring together into one volume a broad discussion coverage of modern signal detection theory applications to human performance, specifically in auditory and visual sensory tasks. Applications address problems in psychology including the integration of sensory information, signal uncertainty, auditory frequency analysis, speech communication, vigilance and recognition memory. Bibliography updated to 1988.
Hardcover. 734 pages. ISBN: 9780932146212
Signal Detection Theory and Psychophysics. David Green and John Swets. Summarizes the application of signal detection theory to the analysis and measurement of the human observer’s sensory system. Outlines the theory of statistical decision making and its application to a variety of common psychophysical activities. Applies signal detection theory to problems in a sensory psychology.
Hardcover. 521 pages. ISBN: 9780932146236
Applied Acoustics. G. Porges. Develops the basic theory of sound from first principles and applies the theory to obtain practical formula for the transmission and absorption of sound, sound levels in closed spaces and the radiation of sound from common noise sources. In keeping with the practical orientation of the book, the mathematics used is relatively elementary.
Hardcover. 190 pages. ISBN: 9780932146182
The Sabines at Riverbank. John Kopec. Chronicles the people and research involved in the birth and first decades of the science of architectural acoustics. Here is the history of the first family of architectural acoustics, the Sabines, and the Riverbank Acoustical Laboratories, the world’s first independent laboratory for measuring the acoustical properties of architectural materials. The story begins in the early 1900s with Wallace Clement Sabine, a Harvard professor, who led the practice of acoustics toward a quantitative science with great insight, industry and integrity. He was followed by two other giants in the field of architectural acoustics: Paul Earls Sabine, a cousin, and his son, Hale Johnson Sabine, all Harvard graduates. No one other than John Kopec with his historical perspective and inside knowledge of the lab could have authored this extraordinary history.
Hardcover. 230 pages. ISBN: 9780932146618
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This is of interest to ATIcourses sonar group. It is clear that the towed sonar array would have detected the nearby submarine. There was not that much surface ship could do to maneuver to prevent the submarine from hitting the towed array. Conversely the submarine should have known that this class of surface ship was […]
This is of interest to ATIcourses sonar group. It is clear that the towed sonar array would have detected the nearby submarine. There was not that much surface ship could do to maneuver to prevent the submarine from hitting the towed array. Conversely the submarine should have known that this class of surface ship was towing an array. I personally doubt that this was inadvertently.
A Chinese submarine hit an underwater towed array sonar being towed by the destroyer USS John McCain on Thursday.
The array was damaged, but the sub and the ship did not collide, the official said. A sonar array is a device towed behind a ship that listens and locates underwater sounds.
The incident occurred near Subic Bay off the coast of the Philippines.
The official, who declined to be named because the incident had not been made public, would not say whether the U.S. ship knew the submarine was that close to it. But of course the sonar knew the submarine was close, but could not maneuver to get out of the way.
However, the Navy does not believe this was a deliberate incident of Chinese harassment, as it would have been extremely dangerous had the array gotten caught in the submarine’s propellers.
The Navy has complained in the past that Chinese vessels, including fishing boats, have deliberately tried to disrupt U.S. naval activities in international waters near China. In one widely publicized incident in March, five Chinese vessels maneuvered close enough to the USNS Impeccable to warrant the use of a fire hose by the unarmed American vessel to avoid a collision. The Navy later released video of that incident.
ATIcourses teaches short courses in underwater sound, sonar and acoustics. See our schedule for our technical training seminars at ATI Training Courses Here are some acoustic and underwater sound conferences that we include as a service to our readers. June 22-26, 2009 – Third International Conference And Exhibition On Underwater Acoustic Measurements: Technology And Results, […]
FINDING THE SPOT “They’ll have to work with flotsam,” he said. “You get the wind and current data and work back. You have to distinguish between the light material that is on the surface and exposed to the wind, and the buoyant material, which is floating, but just under the surface and not exposed to […]
FINDING THE SPOT
“They’ll have to work with flotsam,” he said. “You get the wind and current data and work back. You have to distinguish between the light material that is on the surface and exposed to the wind, and the buoyant material, which is floating, but just under the surface and not exposed to the winds.”
Chris German, the chief scientist for the deep submergence group at the Woods Hole Oceanographic Institute on Cape Cod, said that even with two debris fields located miles apart, the backtracking can be done.
“You look at the ocean currents and wind and determine where the debris was 10 hours before, then 10 hours before that. You do that all the way back to when you think the crash occurred.” Fish said that the hindcasting could trace out the path up to 30 days back in time
Video explaining the sonar search is shown at
This is an interesting article about a Navy Captain who served in submarines and was involved in tracking one of the first Soviet submarines patrolling off the Atlantic coast of the US. The incident used passive sonar to track a Zulu submarine in May 28, 1959 and was able to direct a patrol plane to […]
This is an interesting article about a Navy Captain who served in submarines and was involved in tracking one of the first Soviet submarines patrolling off the Atlantic coast of the US. The incident used passive sonar to track a Zulu submarine in May 28, 1959 and was able to direct a patrol plane to photograph the submarine as it surfaced to recharge its batteries. This was an intelligence bonanza for the US.
Six sonar experts will gather in Newport, Rhode Island in June 1-4 to teach an innovative new course, Advanced Topics in Underwater Acoustics. This four-day course summarizes some of the “leading-edge” topics in underwater acoustics, providing an in-depth treatment of current topics of interest. Focus areas are sound propagation in deep and shallow water, ambient […]
Six sonar experts will gather in Newport, Rhode Island in June 1-4 to teach an innovative new course, Advanced Topics in Underwater Acoustics. This four-day course summarizes some of the “leading-edge” topics in underwater acoustics, providing an in-depth treatment of current topics of interest. Focus areas are sound propagation in deep and shallow water, ambient noise, sonar arrays, sonar signal processing, active sonar technology, and marine mammals mitigation.
The instructors, who are well-known authorities in the field, each have 30 to 40 years of experience in underwater acoustics. Instructors include William Carey, Allan Pierce, Richard Evans, Edmund J. Sullivan, Bill Ellison and Peter G. Cable. Dr. William Carey and Dr. Allan D. Pierce are both professors of Mechanical Engineering at Boston University, and Associate Editor and Editor-in-Chief, respectively, of the Journal of the Acoustical Society of America. Dr. Evans has conducted workshops that led to the standardization of Navy models for underwater sound propagation. Dr. Edmund J. Sullivan was a leading researcher at the Naval Undersea Warfare Center and head of the Signal Processing Group at the SACLANT Undersea Research Centre. Dr. Sullivan has published numerous journal articles, 2 encyclopedia articles, 6 book chapters, and government reports covering the subjects of Underwater Acoustics, Signal Processing, and Electromagnetics. Peter G. Cable was a Principal Scientist at the Naval Undersea Warfare Center and BBN Technologies where he was engaged in acoustic signal processing and sonar system studies.
The course will be close to one of the Navy’s leading research centers, the Naval Undersea Warfare Center in Newport, RI, so that NUWC employees can take advantage of the training, while minimizing travel costs.
ATI the leader in scientific and technical training since 1984, will be hosting the course. To register, contact, Applied Technology Institute at (888) 501-2100 or register online at www.ATIcourses.com.
Jim Jenkins and Ed McCarthy (and families) from ATIcourses.com went fishing on April 28, 2009. We left from Chesapeake Beach, Maryland with Captain Russel on the Carol G. The Captain used high frequency sonar to locate the best fishing holes and to alert when fish past near the boat. He also used a high-tech planar board […]
Jim Jenkins and Ed McCarthy (and families) from ATIcourses.com went fishing on April 28, 2009. We left from Chesapeake Beach, Maryland with Captain Russel on the Carol G. The Captain used high frequency sonar to locate the best fishing holes and to alert when fish past near the boat. He also used a high-tech planar board ( or out-rigger sled) to fish more lines to both sides of the boat.
It was a clear, sunny day. The fishing was great. Six rockfish (also known as striped bass) were caught in about 6 hours. The biggest were 47 and 37 inches. Both are really big fish. The 47 incher approaches the state record holder ( 52 inches in length, but more weight). The fish was shared by all and was mighty tasty.
During the trophy season that runs through May 15, anglers may catch one striped bass per day measuring over 28 inches in the lower Potomac River and throughout much of the Chesapeake Bay.
The striped bass, named the official fish of the State of Maryland in 1965, gets its name from the seven or eight dark stripes that run from head to tail. The fish has an olive green back, fading to light silver on its sides, with a white underside. Known for its size and ability to put up a good fight, the striped bass is considered by many to be the premier sport fish on the Bay. It is also mighty tasty.
Jim’s comments This actually is favorable. First the sound levels are very high and the hearing loss was temporary. “The deafness, though, was only temporary and the dolphin was not hurt in the experiment”. “The hearing was typically restored after 20 minutes, and its loss only occurred after the dolphin was exposed to five rounds […]
This actually is favorable. First the sound levels are very high and the hearing loss was temporary. “The deafness, though, was only temporary and the dolphin was not hurt in the experiment”. “The hearing was typically restored after 20 minutes, and its loss only occurred after the dolphin was exposed to five rounds of noise.”
Secondly the animal was restrained, but in the wild the dolphin can move away our turn its body. The levels are equivalent to a very high level in the peak of a sonar beam. “The sound levels that we used were essentially the equivalent of if an animal is about 40 metres (yards) from the sonar source” . That would mean a source level of 203 + 32 = 235dB re 1 uPa at 1 meter. But the sound typically reduces as 20 Log (Range) from 1 to hundreds of meters. At 100 m the sound is reduced by 40 dB and at 300 m the sound is reduced by 50 dB.
Powerful sonar causes deafness in dolphins: study AFP/File – Dolphins swim off the coast of the Tuamotu islands in French Polynesia. Very loud, repeated blasts of …
Tue Apr 7, 7:05 pm ET
PARIS (AFP) – Very loud, repeated blasts of sonar can cause a dolphin to temporarily lose its hearing, according to an investigation into a suspected link between naval operations and cetacean strandings.
Numerous beachings of whales, dolphins and porpoises have occurred over the past decade, prompting a finger of blame to be pointed at warship exercises.
A theory is that the mammals’ hearing becomes damaged by the powerful mid-frequency sonar used by submarines and surface vessels, prompting the creatures, which themselves use sound for navigation, to become disoriented.
A paper published in the British journal Biology Letters on Wednesday provides the first lab-scale investigation into this idea, although its authors stress it does not provide proof that warship sonar is to blame.
Marine biologists led by Aran Mooney at the University of Hawaii exposed a captive-born, trained Atlantic bottlenose dolphin to progressively louder pings of mid-frequency sonar.
The experiment took place in open water pens at the Hawaii Institute of Marine Biology and in the presence of the dolphin’s trainer.
The scientists fitted a harmless suction cup to the dolphin’s head, with a sensor attached that monitored the animal’s brainwaves.
When the pings reached 203 decibels and were repeated, the neurological data showed the mammal had become deaf, for its brain no longer responded to sound.
The deafness, though, was only temporary and the dolphin was not hurt in the experiment, said Mooney.
The hearing was typically restored after 20 minutes, and its loss only occurred after the dolphin was exposed to five rounds of noise. Each round comprised a block of three pings, with 24 seconds between each block.
Other sensors showed that the dolphin’s breathing rose significantly when the sonar was turned on.
“We definitely showed that there are physiological and some behavioural effects [from repeated, loud sonar], but to extrapolate that into the wild, we don’t really know,” Mooney said in an interview with AFP.
“The sound levels that we used were essentially the equivalent of if an animal is about 40 metres (yards) from the sonar source,” he said.
“The animal would have to be there for about two minutes or so” to get the same level of exposure as in the Hawaii experiment.
“That’s a pretty long time for an animal to be there. If the sound’s pretty loud and the animal’s not used to it, he would move around, and the ship itself is moving in a different direction.”
On the other hand, a cetacean that sought to escape a persistent loud sonar may not easily find an escape route, said Mooney.
“In the ocean, sound doesn’t attenuate in a normal fashion. Sound can sometimes get trapped at the surface, in layers called thermoclines, at the top 100 metres (325 feet) or so.
“Maybe in those conditions it’s more difficult to get away from the sound to a quieter area.”
Further work is needed to figure out what happens at lower sound levels from sonar and at greater distances to see how cetaceans respond, he said.
UK & Canada. Kongsberg Mesotech introduces new sonar products at Ocean Business Tuesday, 31 March 2009 Two new sonar products from Kongsberg Maritime’s specialist sonar division, Kongsberg Mesotech Ltd will be on display at Ocean Business 09. The 1171 Series is a complete range of multi-frequency, fast scanning obstacle avoidance imaging and profiling sonars offering […]
UK & Canada. Kongsberg Mesotech introduces new sonar products at Ocean Business
Tuesday, 31 March 2009
Two new sonar products from Kongsberg Maritime’s specialist sonar division, Kongsberg Mesotech Ltd will be on display at Ocean Business 09. The 1171 Series is a complete range of multi-frequency, fast scanning obstacle avoidance imaging and profiling sonars offering unrivalled resolution, from an industry leader in sonar technology.
The 1171 Series of sonar heads has been developed to meet the requirements for both shallow and deep ocean applications. As well as the choice of operating frequencies, the new sonar heads feature faster scanning rates, improved range resolution and even clearer, sharper images, all in a more compact lighter housing.
1171 Series – Obstacle Avoidance Imaging Sonar Heads:
The dual transducer design allows optimised operational configuration for both long range obstacle avoidance and shorter range imaging detail. The transducer is protected within an oil-filled, pressure compensating dome. The telemetry is RS485 and RS232 compatible and is automatically sensed and configured at start up to match the telemetry link used. The sonar head operation is configured and controlled using the MS1000 Software Processor. Other features include:
-Dual transducers for multi purpose obstacle avoidance and inspection use.
-Multiple frequency capability (330 to 400 kHz and 450 to 700 kHz).
-Improved range and scanning rate.
-Improved sampling resolution & beam foot print resulting in clearer, sharper images.
-Improved Range Resolution.
-Lighter 4000m depth rated design.
-Optional Ethernet telemetry interface.
1171 Series – Multi Frequency Profiling Heads:
The Multi-Frequency design allows optimising of the profiling configuration for different applications. Like the sonar head, the transducer is protected within an oil-filled, pressure compensating dome and the telemetry is automatically sensed and configured at start up to match the telemetry link used. The sonar head operation is also configured and controlled using the MS1000 Software Processor.
-Multiple frequency capability (675kHz to 1.35 mHz).
-Improved range and scanning rate.
-Clearer, sharper images and a >0.5 cm range resolution.
-Sample resolution of > 0.5mm.
-Lighter 4000m depth rated design.
-Optional Ethernet telemetry interface.
Kongsberg Mesotech Ltd. is the Canadian subsidiary of Kongsberg Maritime. Today the company supplies a worldwide customer base with a range of products for military, fisheries, oilfield, scientific, and other offshore market applications.
Kongsberg Mesotech’s strength lies in its unique engineering capabilities. Ongoing research and development has ensured the company’s position as a world-leader in high-resolution sonar systems, and acoustic technology. Kongsberg Mesotech manufactures over 100 models of multibeam, scanning, echo sounder, and altimeter sonar combinations.
CLEVELAND (AP) – Flanked by wide-eyed colleagues, Lorry Wagner holds tight to the line that disappears into a frigid, murky Lake Erie. The three men peer anxiously over the edge of a weather-beaten tugboat, 3-1/2 miles off Cleveland’s downtown shore. At the end of the line is an 80-pound prize – not a monster fish, […]
CLEVELAND (AP) – Flanked by wide-eyed colleagues, Lorry Wagner holds tight to the line that disappears into a frigid, murky Lake Erie.
The three men peer anxiously over the edge of a weather-beaten tugboat, 3-1/2 miles off Cleveland’s downtown shore.
At the end of the line is an 80-pound prize – not a monster fish, but a $20,000 sonar that measures ice thickness. It’s vital information, if wind turbines are to rise in these waters, near Cleveland’s water-intake crib.
The sonar – essentially, an upside-down fish finder, Wagner says – will sit till early April, pinging out sound waves that gauge the thickness of ice overhead.
To calculate the power of moving ice, Matthiesen and others at Case’s Great Lakes Institute for Energy Innovation will link the data on ice thickness with the movement of ice floes. A camera mounted nearby on the city’s water-intake crib is tracking that movement.
“ Nobody has this kind of data,” said Matthiesen, a task force member. “We’ve got to have it.”
Several years ago ATI constructed a list of recommended books for acoustics. We would like to update the list and request your suggestions of the most useful books. https://aticourses.com/acoustics_books.htm Thank you!
Several years ago ATI constructed a list of recommended books for acoustics. We would like to update the list and request your suggestions of the most useful books.