An algorithm for designing a broadband active sound control system

Ross, C.F.

doi:10.1016/0022-460x(82)90278-4

Cited by 31 publications

(4 citation statements)

References 4 publications

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“…This transfer function is then approximated in terms of weighting coefficients obtained by system identification, introducing an error sequence and its minimization by the least-squares method. Details of this algorithm can be found in Ross (1982). The resulting filters were actually tried on a square duct (between 15 to 20 dB of reduction was achieved from 25 to 350 Hz) and also in the entrance lobby of the R.S.R.E.…”

Section: Propagation Of Acoustive Waves In Turbulence; and Active Soumentioning

confidence: 99%

Acoustics of turbulent flows: a report on Euromech 142

1982

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The European Mechanics Colloquium, Euromech 142, ww held at the Ecole Centrale de Lyon from 23 to 26 September 1981 and WM attended by 70 participants, from 9 countries, active in the fields of (i) sound production by turbulent flows and (ii) the effects of flow and turbulence on the propagation of acoustic waves. For topic (i), attention was mostly paid to shear-layer and jet instabilities and to the flow-surface interaction of flexible boundaries, vibrating blades and rigid thick airfoils. Applications were concerned in particular with propeller noise and airframe self-noise of large aircraft. Impinging shear layers were also considered for single and multiple cavities in which self-sustained oscillations can occur. Another subject discussed at the meeting was the noise from inhomogeneities, with applications to flames. For topic (ii), theoretical formulations were presented for the far field of moving multipole sources in the presence of flow and for sound propagation in ducts of variable cross section, with flow, for frequencies around the cut-off. The effect of turbulence was investigated in terms of the space–time coherence of the transmitted pressure fields. Broadband active sound control in the presence of flow was also considered, with emphasis on the progress made possible by use of digital filters. Finally, new experimental techniques, such as acoustic intensity measurements, were presented and large anechoic wind tunnels and other acoustic facilities were described.

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Section: Propagation Of Acoustive Waves In Turbulence; and Active Soumentioning

confidence: 99%

Acoustics of turbulent flows: a report on Euromech 142

1982

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“…Active noise control (ANC) in three-dimensional enclosed spaces such as automobile interiors, aircraft cabins, and rooms in buildings seems to introduce significantly greater difficulties compared with that in free fields or one-dimensional enclosures [1][2] . Since a large number of sound reflections and reverberation exist along with the primary noise signal, an inverse model control using a considerably complex reference model is required in place of the simple "delay and out-phase" method.…”

Section: Introductionmentioning

confidence: 99%

An Alternative Inverse Filter for Global Noise Control in a Small Enclosure

TAMADA

2023

8th European Conference on Noise Control 2009

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In this article, an alternative method to estimate inverse filters is presented for the global noise control in a small enclosure. This method requires a priori system modeling by the modal decomposition of impulse responses between primary/control sources and error sensors. The theoretical development is based upon minimizing the signal energy of impulse responses. The performance of control using this method was investigated through computer simulations. As a result, it was confirmed that the obtained inverse filter would have an ability to accomplish the global noise reduction.

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“…3 Ross presented a convenient algorithm to calculate a closed loop active noise controller. 4 Eghtesadi et al developed a modified control system into which a compensating circuit was introduced to prevent the instability due to acoustic feedback. 5 Trinder et al reintroduced the acoustic virtual earth method into active noise control in a duct.…”

Section: Introductionmentioning

confidence: 99%

A state feedback electro-acoustic transducer for active control of acoustic impedance

Samejima¹

2003

The Journal of the Acoustical Society of America

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In this paper, a new control system in which the acoustic impedance of an electro-acoustic transducer diaphragm can be actively varied by modifying design parameters is presented and its effectiveness is theoretically investigated. The proposed control system is based on a state-space description of the control system derived from an electrical equivalent circuit of an electro-acoustic transducer to which a differentiating circuit is connected, and is designed using modem control theory. The optimal quadratic regulator is used in the control system design, with its quadratic performance index formulated for producing desired acoustic impedance. Computer simulations indicate that the acoustic impedance of the diaphragm can be significantly varied over a wide frequency range that includes the range below the resonance frequency of the electro-acoustic transducer. A computer model of the proposed control system is used to illustrate its application to semi-active noise control in a duct. It is demonstrated that the proposed control system provides substantial reductions in the noise radiating from the outlet of the duct, both in the stiffness control range and in the mass control range.

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An algorithm for designing a broadband active sound control system

Cited by 31 publications

References 4 publications

Acoustics of turbulent flows: a report on Euromech 142

Acoustics of turbulent flows: a report on Euromech 142

An Alternative Inverse Filter for Global Noise Control in a Small Enclosure

A state feedback electro-acoustic transducer for active control of acoustic impedance

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