21. Science Central : Science - Technology - Acoustics, Ultrasound And Vibration - A Provides answers to common questions about active noise control including a Products from a manufacturer of active noise and vibration control systems http://www.sciencecentral.com/category/48634

Thursday, 24 January, 2008 Home Submit Science Site Add to Favorite Contact search for Directories Aeronautics and Aerospace Agriculture Anomalies and Alternative Science Astronomy ... Technology Category: Science Technology Acoustics, Ultrasound and Vibration Active Noise Control SUBMIT A SITE Active Noise Control Order by Popularity Alphabet Sites Records 1-5 of 5 BoscoItalia S.p.A. (Italy) (Popularity: company in the sector of the industrial noise, noise reduction systems in all industrial fields: ... Active Noise Control for Smart Materials (Popularity: Research results and software tools for using smart materials in active noise control. Active noise ... Frequently Asked Questions about Active Noise Control (Popularity: Provides answers to common questions about active noise control including a discussion of popular misconceptions ... Lord Corporation NVX Active Systems (Popularity: Products from a manufacturer of active noise and vibration control systems for passenger aircraft. Virginia Tech Vibration and Acoustics Lab (Popularity: Research at Virginia Tech.

22. Active Noise Control Primer He candidly admits that to date the practical (author s emphasis) applications of active noise control are few. However, having said that it is also http://www.iop.org/EJ/abstract/0957-0233/12/5/705

@import url(http://ej.iop.org/style/nu/EJ.css); User guide Site map Athens login IOP login: Password: Create account Alerts Contact us Journals Home ... Content finder BOOK REVIEW Active Noise Control Primer Scott D Snyder Meas. Sci. Technol. 654 doi:10.1088/0957-0233/12/5/705 Scott D Snyder ISBN 387 98951 X (hbk) It is rather rare for an active researcher in a particular discipline to be critical about the contributions made by his/her field of research towards technology. As becomes apparent by reading the preface, the author of this book is refreshingly different. He candidly admits that to date the practical (author's emphasis) applications of active noise control are few. However, having said that it is also apparent from the hundreds of archival publications that there are success stories, and to quote the author again `when active noise control works, it really works'. Graduate students and professionals who are new to the field of active control are often faced with the fact that they need a working knowledge of several fields, such as microelectronics and digital signal processing, in addition to being well versed in acoustics and noise control. This book certainly fills the need of such readers and assumes no background in any of the fields mentioned above. From the free-field problems the author moves to enclosed sound fields in chapter 5 and the treatment of passive control measures, which is rather short. In fact this chapter is rather short in its treatment of either active or passive noise control measures, considering that enclosed sound field control has been the motivating factor for active control. However, in the next chapter on duct acoustics, sufficient discussion on the do's and don'ts of active noise control can be found. The final two chapters are really well written and enlighten readers on the digital and signal processing aspects of active control. The final chapter is the longest and is a very good introduction to adaptive feedforward controller characteristics and what is desirable for the design of good controllers. Important issues such as sampling rates, quantization errors, leakage and convergence issues are addressed adequately.

23. Professor Makes Noise With Active Control Scott D. Sommerfeldt, an associate professor of physics, is at the forefront of active noise control research and the struggle against noise. http://magazine.byu.edu/g/viewarticle.php?a=189

24. Preface Of Active Noise Control Book active noise control Systems Algorithms and DSP Implementations 1 Introduction to active noise control. 1.1 General Concept. 1.2 General Applications http://www.ceet.niu.edu/faculty/kuo/books/acns/contents.html

Active Noise Control Systems - Algorithms and DSP Implementations Sen M. Kuo and Dennis R. Morgan Contents Preface Acknowledgments Introduction to Active Noise Control General Concept General Applications Air-Acoustic ANC Hydroacoustic ANC Vibration ANC ANC Systems Broadband Feedforward ANC Systems Narrowband Feedforward ANC Systems Feedback ANC Systems Multiple-Channel ANC System Performance Evaluation Adaptive Transversal Filters Introduction to Adaptive Systems Adaptive Algorithms MSE Performance Surface Method of Steepest Descent LMS Algorithm Performance Analysis of the LMS Algorithm The Stability Constraint Time Constant of the Adaptive Process Excess Mean-Square Error Modified LMS Algorithms Normalized LMS Algorithm Correlation LMS Algorithm Leaky LMS Algorithm Partial-Update LMS Algorithm Variable-Step-Size LMS Algorithm Signed LMS Algorithms Complex LMS Algorithm Analysis of Adaptive Systems Using the z -Transform Applications Adaptive Noise Cancellation Adaptive System Identification Adaptive Linear Prediction Broadband Feedforward Active Noise Control Basic Principles Simplified System Identification Scheme Coherence Secondary-Path Effects FXLMS Algorithm and Off-Line Secondary-Path Modeling Derivation of the FXLMS Algorithm Analysis of the FXLMS Algorithm Secondary-Path Equalization Off-Line Modeling Technique Effects of Modeling Errors Effects of Measurement Noise Leaky FXLMS Algorithm Feedback Effects and Solutions Effects of Feedback Feedback Neutralization Dual-Microphone Reference Sensing System Other Acoustic Arrangements

25. Active Noise Control Equipment - US (United States) Find active noise control Equipment suppliers in US. Kellysearch has 26 companies listed for active noise control Equipment. http://www.kellysearch.com/us-product-119712.html

Suppliers News Web Search Add my company ... Advertise Worldwide United States United Kingdom Asia Africa Middle East Australasia Europe North America South America Southeast Asia Australia Canada China Finland Germany Hong Kong India Indonesia Ireland Japan Netherlands New Zealand Norway Malaysia Singapore South Africa Sweden Taiwan Thailand Vietnam Product/Service Company Click to refine by region or country Worldwide (27) Africa (1) Asia (1) Australasia (2) ... UK (7) US (11) California (CA) (1) Georgia (GA) (1) Massachusetts (MA) (1) Michigan (MI) (1) ... Active Noise Control Equipment US Active Noise Control Equipment Suppliers - US (United States) More in this sector... 3 Pass Fire Tube Boilers ABS Water Booster Units ASME Standard Boiler Heads ATEX Certified Explosion Protected (EX) Electric Process Heating Systems ... More terms... 1 - 11 of American results ArtUSA Industries Atlanta, GA, US ARTUSA INDUSTRIES, is a company that is leading the nation in cost effective Noise Control , Sound Enclosures and Air Filtration Systems. We offer complete design, engineering, fabrication and installation capabilities for all of our products. Details Save Share www.noisecontrolproducts.com/active_noise_cancelin...

26. Inverse Structure For Active Noise Control And Combined Active In this paper, a simple inverse structure for multichannel active noise control ANC is introduced, based on the use of noncausal models of the pseudo http://citeseer.ist.psu.edu/722548.html

27. 3.3. What Universities Teach Active Noise Control? alt.sci.physics.acoustics FAQ . What universities teach active noise control? http://stason.org/TULARC/physics/noise-control-faq/3-3-What-universities-teach-a

stason.org TULARC Physics Active Noise Control 3.3. What universities teach active noise control? stason.org Articles Development Books ... Site Map Search Favorites Chest of Books I want a better... Meta Religion StasoSphere ... MailChannels Hosted by Description This article is from the Active Noise Control FAQ , by Dr. Chris Ruckman 3.3. What universities teach active noise control? Some readers may wish to contact universities regarding curricula that include active noise control. Many universities teach active noise control (primarily at the graduate level). The following schools, LISTED IN ALPHABETICAL ORDER, have reasonably extensive graduate research programs in active noise control. No endorsement of any kind is implied by inclusion in this list, nor is this meant to be a complete list. [Editor's note: Please help me add to this list, especially universities outside the USA. CR] * Delft University of Technology, Delft, Netherlands http://www.tudelft.nl/home.html * Duke University, Durham, North Carolina, USA http://www.duke.edu/ * Georgia Institute of Technology, Atlanta, Georgia, USA http://www.gatech.edu/

28. Active Noise Reduction, Sound Insulation, Noise Control Solutions Silentium is leading in providing advanced noise reduction solutions, utilizing its unique active noise control technology (ANC) (also known as noise http://www.silentium.com/

AC_FL_RunContent( 'codebase','http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,28,0','width','758','height','222','title','silence in a chip','src','flash_04','quality','high','pluginspage','http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash','movie','flash_04' ); //end AC code Company Technology News Events ... Contact Form cssdropdown.startchrome("chromemenu") CeBIT 2008 Come and see our innovative solutions , Hall 2 booth C49 Active Noise Solutions Rackmount Cabinet ActiveSilenser Duct ActiveSilenser Docking Station We are looking for business partners If you are Distributor, System Integrator or IT consultant, you are welcome to contact us sound before sound after Listen to an audio presentation giving 'before' and 'after' recordings of the AcoustiRACK active Cabinet. Noise pollution, usually generated by fans and motors is one of the most irritating phenomena accompanies modern life. Silentium is leading in providing advanced noise reduction solutions, utilizing its unique Active noise control technology (ANC) (also known as noise cancellation, active noise reduction (ANR) or antinoise). Silentium’s sound insulation solution is based on its S-Cube Kit and is implemented in servers, soundproof rackmount cabinets, AC systems, personal computers (pc) etc.

29. Active Noise Control By the usage of signal processors it has became possible to utilize different active noise control methods. These are based on the phenomenon of the http://home.mit.bme.hu/~sujbert/active.html

Introduction Passive suppression of low-frequency noise or vibration has numerous disadvantages, mainly because of the volume of the absorbers. By the usage of signal processors it has became possible to utilize different active noise control methods. These are based on the phenomenon of the destructive interference. A "secondary" noise has to be generated, which suppresses the "primary" (i.e. the original) noise at the properly situated microphones. The whole problem has both acoustical and control aspects. In some cases, if the secondary source can be implemented near to the primary source (e.g. a ventilation duct), a single loudspeaker - microphone pair is enough. In other cases, if the noise source is not concentrated, and the suppression in an enclosure has to be achieved (e.g. an airplane), more loudspeakers and microphones are utilized. Active noise control is a new research and development direction at our department. However, the knowledge-base in measurement, system identification and signal processing helps us to obtain new results in this field. Technical Background Active noise control requires multifarious knowledge, such as measurement, analog and digital signal processing and acoustics. Design of active noise control systems needs

30. The MathWorks - Filter Design Toolbox - Active Noise Control Using A Filtered-X This demonstration illustrates the application of adaptive filters to the attenuation of acoustic noise via active noise control. http://www.mathworks.com/products/filterdesign/demos.html?file=/products/demos/s

31. First Test Of Fan Active Noise Control (ANC) Completed active noise control (ANC) holds promise as a solution to this problem. It uses secondary (added) noise sources to reduce or eliminate the offending noise http://www.grc.nasa.gov/WWW/RT1995/2000/2770h.htm

First Test of Fan Active Noise Control (ANC) Completed With the advent of ultrahigh-bypass engines, the space available for passive acoustic treatment is becoming more limited, whereas noise regulations are becoming more stringent. Active noise control (ANC) holds promise as a solution to this problem. It uses secondary (added) noise sources to reduce or eliminate the offending noise radiation. The first active noise control test on the low-speed fan test bed was a General Electric Company system designed to control either the exhaust or inlet fan tone. This system consists of a "ring source," an induct array of error microphones, and a control computer. Fan tone noise propagates in a duct in the form of spinning waves. These waves are detected by the microphone array, and the computer identifies their spinning structure. The computer then controls the "ring source" to generate waves that have the same spinning structure and amplitude, but 180° out of phase with the fan noise. This computer-generated tone cancels the fan tone before it radiates from the duct and is heard in the far field. The "ring source" used in these tests is a cylindrical array of 16 flat-plate acoustic radiators that are driven by thin piezoceramic sheets bonded to their back surfaces. The resulting source can produce spinning waves up to mode 7 at levels high enough to cancel the fan tone. The control software is flexible enough to work on spinning mode orders from -6 to 6. In this test, the fan was configured to produce a tone of order 6.

32. Advances In Acoustics And Vibration — An Open Access Journal Global active noise control in an entire enclosure or a large freefield area is For many active noise control applications, even those based on virtual http://www.hindawi.com/journals/aav/si/anc.html

Advanced search Hindawi Publishing Corporation Home Journals About Us About this Journal ... Table of Contents Journal Menu Aims and Scope Article Processing Charges Author Guidelines Bibliographic Information ... Special Issue Guidelines Active Noise Control Call for Papers Therefore, more microphones and loudspeakers are often necessary. In the most general case, a coupling between subsequent pairs (channels) should be taken into account resulting in a multichannel system. Another successful control strategy is to shift the zones of quiet to desired locations without performing measurements at those locations. Such strategy can also be performed in a multichannel structure. This special issue of the journal aims to report on the latest research and development findings related to active control of acoustic noise. Papers concentrating on physical analysis, optimal and adaptive control, or single and multi-channel systems will be appreciated. The main topics of the special issue include but are not limited to the following: Generating zones of quiet Extending zones of quiet Virtual-microphone control systems Single and multichannel control systems Optimal control systems Adaptive control systems Feedforward, feedback, and combined systems

33. Active Noise Control (ANC) | Portable Audio Devices - CNET Reviews Portable Audio Devices active noise control (ANC). CNET brings you the best reviews for active noise control (ANC) Portable Audio Devices. http://usatoday.com.com/4566-6450_7-0.html?filter=500909_14440432_

34. Active Noise Control System - Patent 7254240 An active noise control system is capable of canceling out noise in the passenger compartment of a vehicle based on lowfrequency road noise. http://www.freepatentsonline.com/7254240.html

Login or Create Free Account Search Go to Advanced Search Home Search Patents Data Services ... Help Title: Active noise control system Document Type and Number: United States Patent 7254240 Link to this page: http://www.freepatentsonline.com/7254240.html Abstract: Inventors: Inoue, Toshio (Tochigi-ken, JP) Sano, Hisashi (Utsunomiya, JP) Takahashi, Akira (Tochigi-ken, JP) Terai, Kenichi (Shijonawate, JP) Hashimoto, Hiroyuki (Daito, JP) Kakuhari, Isao (Ikoma, JP) Application Number: Filing Date: Publication Date: View Patent Images: Images are available in PDF form when logged in. To view PDFs, Login or Create Account (Free!) Referenced by: View patents that cite this patent Export Citation: Click for automatic bibliography generation Assignee: Honda Giken Kogyo Kabushiki Kaisha (Tokyo, JP) Matsushita Electric Industrial Co., Ltd. (Osaka, JP) Primary Class: International Classes: Field of Search: US Patent References: April, 1995 Mason et al. Method and apparatus for reducing noise radiated from a complex vibrating surface July, 1997

35. Campanella Associates (Acoustics Consultants) - Active Noise Control active noise control . Campanella Associates 3201 Ridgewood Drive Columbus, Ohio 43026 614.876.5108 FAX 614.771.8740 (call ahead) a.campanella@att.net http://www.campanellaacoustics.com/anc.html

Active Noise Control or Cancellation (ANC) We have received many inquiries about the feasibility of ANC in reducing domestic and commercial noise problems. The conventional wisdom seems to be that most noise situations are amenable to an ANC solution. This is false, just as is the notion that the computer is the solution to all calculation and bookkeeping problems, or that computers reduce the consumption of paper. Consider that most general noise problems are 3-dimensional in nature, typically a noisy area where one or more persons work or relax. Explanations are needed: ANC uses the principle of destructive interference, where the noise sound wave is sensed with a microphone. This signal is amplified and fed to a loudspeaker which emits sound of the same type but of opposite phase with respect to the original sound wave. Such cancellation can occur at only one point in space. In the case of one-dimensional propagation down a duct, the sound wave for all intents is "stopped" at that point since the sound from the loudspeaker proceeds one - dimensionally down the duct, matching the original noise waves precisely along the way. (upstream toward the sound source, the sound wave is doubled, but that is of no concern. In the case of two or three dimensional propagation into space as into a room, The spreading of the loudspeaker sound does not match the pattern of the divergence of the noise field, having

36. Active Noise Control Of Tilt-Rotor Aircraft BVI is a major source of noise produced by helicopters and tiltrotor aircraft during descent. This noise has been reduced using active control of the blade http://128.102.216.35/factsheets/view.php?id=396

37. Active Noise Control - DiracDelta Science & Engineering Encyclopedia There are many institutions and companies around the world working on the technology to increase the circumstances where ANC can be used effectively. http://www.diracdelta.co.uk/science/source/a/c/active noise control/source.html

A B C D ... Subjects google_ad_client = "pub-5380227926861825";google_ad_width = 120;google_ad_height = 600;google_ad_format = "120x600_as";google_ad_type = "text_image";google_ad_channel ="5378264726";google_color_border = "8DA58E";google_color_bg = "8DA58F";google_color_link = "000000";google_color_url = "666666";google_color_text = "1B3121"; addthis_url = location.href; addthis_title = document.title; addthis_pub = 'charliehawkins'; Active Noise Control This is an electronic method of reducing or removing unwanted sound by the production of a pressure wave of equal amplitude but opposite sign to the unwanted sound. When the electronically produced inverse wave is added to original unwanted sound the result is sound cancellation. This method of noise control is becoming increasingly popular for a variety of uses. It is sometimes considered a miracle "cure-all" for noise problems which, at the present time, is not the case. For example noise cancellation in 3D spaces, such as living areas, is very difficult to achieve. However it can be more successful locally, eg for a passenger sitting in an aircraft or car. There are many institutions and companies around the world working on the technology to increase the circumstances where ANC can be used effectively. In its general form as applied to the vehicles, the technique involves continuous monitoring of the selected parameter(s) whose effect is to be controlled and producing, by means of an electronic method, a cancelling signal. In the case of Active Noise cancellation, for example, the engine noise is the monitored parameter, selected because of its order related nature, and the cancellation is provided by a loud-speaker in the passenger cabin at a carefully chosen location.

38. Active Noise Control Earbuds: Wolverine Data Wolverine active noise control earbuds are perfect companion for MP3 and CD players, portable radios, PC audio or portable DVD players. http://secure.serverlab.net/shop/merchant.mvc?Screen=PROD&Product_Code=ACCE32&Ca

39. Active Noise Control (ANC) | Headphones - CNET Reviews CNET brings you the best reviews for active noise control (ANC) Headphones. You found 1 item for Features active noise control (ANC). Too few results? http://reviews.cnet.com/4566-7877_7-0.html?filter=500909_14440432_

40. Active Noise Control Apparatus - US Patent 6683960 active noise control apparatus US Patent 6683960 from Patent Storm. An active noise control apparatus for transmitting, from a loud speaker, http://www.patentstorm.us/patents/6683960.html

Home Browse by Inventor Browse by Date Links ... Contact Us United States Patent 6683960 Active noise control apparatus US Patent Issued on January 27, 2004 Inventor(s) Kensaku Fujii Juro Ohga Assignee Fujitsu Limited Application No. 641660 filed on 2000-08-18 Current US Class Counterwave generation control path ACOUSTICAL NOISE OR SOUND CANCELLATION Adaptive filter topology Field of Search ACOUSTICAL NOISE OR SOUND CANCELLATION Algorithm or formula (e.g., LMS, Filtered-X, etc.) Analog or nonadaptive Tonal noise or particular frequency or band Acoustic, nonairborne vibration sensing or counterwave emission Within cabin or compartment of vehicle Counterwave generation control path Non-acoustically derived reference signal NOISE OR DISTORTION SUPPRESSION Examiners Primary: Xu Mei Attorney, Agent or Firm Katten Muchin Zavis Rosenman US Patent References Coefficient updating method for an adaptive filter Issued on: September 16, 1997 Inventor: Ohashi Reduction of computational burden of adaptively updating control filter(s) in active systems Issued on: April 28, 1998

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