Thin broadband noise absorption through acoustic reactance control by electro-mechanical coupling without sensor.

نویسندگان

  • Yumin Zhang
  • Yum-Ji Chan
  • Lixi Huang
چکیده

Broadband noise with profound low-frequency profile is prevalent and difficult to be controlled mechanically. This study demonstrates effective broadband sound absorption by reducing the mechanical reactance of a loudspeaker using a shunt circuit through electro-mechanical coupling, which induces reactance with different signs from that of loudspeaker. An RLC shunt circuit is connected to the moving coil to provide an electrically induced mechanical impedance which counters the cavity stiffness at low frequencies and reduces the system inertia above the resonance frequency. A sound absorption coefficient well above 0.5 is demonstrated across frequencies between 150 and 1200 Hz. The performance of the proposed device is superior to existing passive absorbers of the same depth (60 mm), which has lower frequency limits of around 300 Hz. A passive noise absorber is further proposed by paralleling a micro-perforated panel with shunted loudspeaker which shows potentials in absorbing band-limit impulse noise.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Simulation and Modeling of a High Sensitivity Micro-electro-mechanical Systems Capacitive Pressure Sensor with Small Size and Clamped Square Diaphragm

This paper proposes a Micro-electro-mechanical (MEMS) capacitive pressure sensor that relies on the movable electrode displaced like a flat plate equal to the maximum center deflection of diaphragm. The diaphragm, movable electrode and mechanical coupling are made of polysilicon, gold and Si3N4, respectively. The fixed electrode is gold and the substrate is Pyrex glass. This proposed method inc...

متن کامل

Investigation of the efficiency of various reactive mufflers by noise reduction and transmission loss analyses

Transmission loss and noise reduction of reactive mufflers are determined by linear acoustic theory and unsteady flow field study, respectively. The effects of extending the inlet tube of the muffler, adding holes to the extension, and the number of holes on both transmission loss and noise reduction are investigated. In noise reduction analysis, the Navier-Stokes equations and k-ε model are us...

متن کامل

A COMPARISON OF lWO ACTUATORS FOR A SEMI-ACTIVE HELMHOLTZ RESONATOR

Two electro-mechanical actuators are examined for a semi­ active Helmholtz resonator acoustic device. The device is used to reflect narrowband noise back to the source in an acoustic duct. The controller and actuator are used to tune the system on-line allowing optimum performance over a range of operating conditions. Actuator. dynamics play an important role in the controller design and the op...

متن کامل

Preparation and Characterization of Aluminum Nitride Thin Films with the Potential Application in Electro-Acoustic Devices

In this work, aluminum nitride (AlN) thin films with different thicknesses were deposited on quartz and  silicon  substrates  using  single  ion  beam  sputtering  technique.  The  physical  and  chemical properties  of  prepared  films  were  investigated  by  different  characterization  technique.  X-ray diffraction (XRD) spectra revealed that all of the deposited films have an amorphous str...

متن کامل

Aerodynamic Noise Computation of the Flow Field around NACA 0012 Airfoil Using Large Eddy Simulation and Acoustic Analogy

The current study presents the results of the aerodynamic noise prediction of the flow field around a NACA 0012 airfoil at a chord-based Reynolds number of 100,000 and at 8.4 degree angle of attack. An incompressible Large Eddy Simulation (LES) turbulence model is applied to obtain the instantaneous turbulent flow field. The noise prediction is performed by the Ffowcs Williams and Hawkings (FW-...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Journal of the Acoustical Society of America

دوره 135 5  شماره 

صفحات  -

تاریخ انتشار 2014