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Passive tuned loudspeakers as absorbers for room acoustics

Oldfield, RG and Cox, TJ 2007, 'Passive tuned loudspeakers as absorbers for room acoustics' , in: 19th International Congress on Acoustics : acoustics for the 21st century : Madrid, Spain, 2-7 September 2007 , Spanish Acoustical Society, Madrid, Spain.

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This paper presents a novel approach to improving the performance, tunability and efficiency of low frequency membrane absorbers. It is shown that a passive loudspeaker within a cabinet can be used as an efficient and adaptable membrane absorber, with variable passive electronic components connected across the terminals to alter its mechanical resonance properties. This allows the system to be tuned/re-tuned and installed in different rooms without the impractical geometrical re-design and manufacture needed for standard membrane absorbers. Impedance tube data is presented for an absorber with different electronic loads connected. Varying the value of a single capacitor across the loudspeaker terminals is shown to reduce the resonant frequency of the system by up to 30%, whilst varying solely resistive loads is shown to alter the effective bandwidth of absorption. A lumped element model is derived, allowing the system to be optimised for different resistive and reactive component combinations for a specific driver. Absorber systems of this type could find a place in small critical listening environments, where the damping of room modes is vital for good acoustic conditions.

Item Type: Book Section
Editors: Calvo-Manzano, A, Pérez-López, A and Santiago, S
Themes: Built and Human Environment
Schools: Schools > School of Computing, Science and Engineering
Schools > School of Computing, Science and Engineering > Salford Innovation Research Centre (SIRC)
Publisher: Spanish Acoustical Society
Refereed: No
ISBN: 9788487985126
Funders: International Congress on Acoustics (ICA)
Depositing User: RG Oldfield
Date Deposited: 15 Jan 2014 17:59
Last Modified: 01 Dec 2015 00:00

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