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Wednesday, May 13, 2020 | History

3 edition of Active control of multi-dimensional random sound in ducts found in the catalog.

Active control of multi-dimensional random sound in ducts

Richard J. Silcox

Active control of multi-dimensional random sound in ducts

by Richard J. Silcox

  • 278 Want to read
  • 8 Currently reading

Published by National Aeronautics and Space Administration, Langley Research Center in Hampton, Va .
Written in English

    Subjects:
  • Airplanes -- Air ducts -- Noise -- Prevention

  • Edition Notes

    StatementR.J. Silcox, S.J. Elliott.
    SeriesNASA technical memorandum -- 102653.
    ContributionsElliott, S. J., Langley Research Center.
    The Physical Object
    Pagination9, [1] p. :
    ID Numbers
    Open LibraryOL17630471M
    OCLC/WorldCa25053586

    This thesis investigates active noise control over a large spatial region using efficient control systems. Active noise control (ANC) utilises secondary sound sources to cancel primary noise based on the principle of destructive interference, and has the advantage of high flexibility and easy adaptability. ANC over a large spatial region (spatial ANC), which requires multiple . Engineering Noise Control Also available from Spon Press Understanding Active Noise Cancellation Colin Hbk: 0–––4 Spon Press Pbk: 0–––2 Fundamentals of Noise and Vibration Edited by Frank Fahy and John Walker Pbk: 0–––8 Spon Press Active Control of Noise and Vibration Colin and Scott .

    Chapter 10 – Sound in Ducts. Dept. of Mech. Engineering 2 ME Vibro-Acoustic Design Book, On the Sensations of Tone as a Physiological Basis for the Theory of Music, • Resonators used as side branches attenuate sound in the main duct or Size: 2MB. An active noise control scenario of simple ducts is considered. The previously suggested technique of using an single loudspeaker and its rear sound to cancel the upstream sound is further examined and compared to the bidirectional solution in order to give theoretical proof of its advantage. Firstly, a model with a new approach for taking damping effects into account is Author: Karel Kreuter, Yasuhide Kobayashi.

    The active noise control of a one-dimensional hard-walled duct with a partially dissipative boundary condition is addressed in this paper. Previous techniques have attacked this problem by developing adaptive filters designed to cancel acoustic noise at a single measurement by: Inter-noise Page 1 of 10 Active noise control in practice: transformer station Edwin Buikema 1; Fokke D. van der Ploeg 2; Jan H. Granneman 3 1, 2, 3 Peutz bv, Netherlands ABSTRACT Based on literature and extensive measurements at a specific transformer two concepts regarding anti noise have been developed.


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Active control of multi-dimensional random sound in ducts by Richard J. Silcox Download PDF EPUB FB2

Get this from a library. Active control of multi-dimensional random sound in ducts. [Richard J Silcox; S J Elliott; Langley Research Center.]. The application of active control in the multi-dimensional propagation of random noise in waveguides is examined.

An adaptive system is implemented using measured system frequency response functions. Experimental results are presented illustrating attained suppressions of 15 to 30 dB for random noise propagating in multiple modesAuthor: S.

Elliott and R. Silcox. Active Control of Noise and Vibration - CRC Press Book Since the publication of the first edition, considerable progress has been made in the development and application of active noise control (ANC) systems, particularly in the propeller aircraft and automotive industries.

Active adaptive sound control in a duct: A computer simulation. Most active sound cancellation systems reported in the literature use open‐loop control, depend on near‐zero phase delay in control system elements, and require constant acoustic signal transit time from a signal pickup (microphone) to a control sound source (loudspeaker).Cited by: The active control of tonal noise propagating in ducts at frequencies where many modes are able to propagate is considered.

The final objective of the work reported is to cancel the prominent – Hz blade passing frequency of the rotary suction fans found in chimney stacks of power by: 8. multichannel feedforward control of periodic and random sound, discussions of cost functions, and control algorithms to reduce cost functions.

This book would be. The active control of sound propagation in long ducts. A method of attenuating propagating waves in a duct by actively operated sources mounted in the walls of the duct is considered, and a simple control system for the operation of these sources is by: the active control of vibration.

In many cases active control of sound and vibration can be treated as one problem, especially when dealing with struc-ture-borne sound.

In this papera model of active noise control sys-tem for infinite ducts will be developed, useful for modeling of the active noise control systems in the ventilation by: 4.Active control of sound in ducts, Ph.D., Institute of Sound and Vibration Research, 4. es, Active control at the source of noise of a centrifugal fan, In Publications du CETIM, pp.5.

® and al., Active noise control of low speed fan rotor-stator modes, In 3rd AIAA/CEAS Aeroacoustic. Understanding Active Noise Cancellation Provides a concise introduction to the fundamentals and applications of active control of vibration and sound for the non-expert. It is also a useful quick reference for the specialist engineer.

The book emphasises the practical applications of technology, and complex control algorithms and structures are only discussed. However, due to the noise generated by propellers and rotors of a drone, the quality of sound in a video recorded by the drone is quite limited.

In order to solve the noise problem of drones, this paper proposes a novel hybrid noise reduction technique combining Active Noise Control and Spectral subtraction methods. adaptive signal processing skills to active noise control.

This book provides in a simple way the active noise control field and its associated problems. As the book provides only required amount of acoustical details and explains the filtered LMS algorithm very clearly unlike other books, for a beginer it is a very good book.

This paper examines the application of active control to the multi-dimensional propagation of random noise in waveguides.

The problem of designing a realizable controller using a finite impulse response filter and controlling the acoustic feedback path of the control source-detector microphone path are addressed using an acoustically lined section.

A digital computer simulation of adaptive closed-loop control for a specific application (sound cancellation in a duct) is discussed. The principal element is an extension of Sondhi's adaptive echo canceler and Widrow's adaptive noise canceler from signal processing to control.

Thus, the adaptive algorithm is based on the LMS gradient search. In this paper, an indirect feedback active noise control (ANC) scheme, based on the fundamental frequency-estimation method, is proposed for systems with multiple tonal noises.

The engine noise consists of the harmonic components of the rotation of the crankshaft in the engine. When it is difficult to obtain reference signals, which are necessary for a feedforward Cited by: 8. passive silencers commonly used to attenuate the ventilation noise are not effective in the low-frequency range.

A method proven to effectively reduce low-frequency noise in a wide variety of applications is active noise control (ANC). A feedforward ANC system applied to duct noise. An active noise control system incorporating a virtual sensing method thus has to be able to create a moving zone of quiet that tracks the observer’s by: X.

Kong, S.M. Kuo: Analysis of asymmetric out-of-band overshoot in narrowband active noise control systems, IEEE Trans. Speech Audio Process.

7, Cited by: Active Noise Control Primer (Modern Acoustics and Signal Processing) [Snyder, Scott D.] on *FREE* shipping on qualifying offers. Active Noise Control Primer (Modern Acoustics and Signal Processing)/5(3).

While the use of active noise control in ducts has met with considerable success, • its application to three-dimen- sional sound fields (as opposed to one-dimensional plane waves) has not. Recent work 2 has demonstrated that the acoustic control mechanism in a duct.

"A new 1,page reference book, "Handbook of Noise and Vibration Control," intended to be the definitive source on noise and vibration control for engineers, scientists, and researchers. The new reference book addresses a range of topics in acoustics and vibration, focusing on industrial needs.".Active control of sound is a technique for altering acoustic fields to a desired one by introducing controllable active secondary sound sources called controls.

An example problem formulation in this area involves a given region of space (bounded or unbounded) to be shielded from unwanted external noise by the active controls. The controls.Abstract. We deal with the design of active noise control systems for ventilation ducts with a pair of loud-speakers based on sampled-data optimization, in order to improve our previous study with a single loudspeaker.

The resultant controller requires lower computational complexity for the implementation, compared to the standard time-varying adaptive controllers, since it is time Cited by: 5.