Acoustic Pressure Minimization for Diffuse Fields

Abstract:

In this paper performance of actively controlling diffuse fields using acoustic pressure minimization has been presented. The technique is -norm acoustic pressure minimization. The theory and simulations of pressure minimization over space and frequency using two-channel and three-channel systems are presented. This paper focuses on diffuse primary fields with two and three secondary sources. A constrained pressure minimization is also introduced in this paper, to control pressure at various spaces and frequencies. The results show that a good attenuation is achieved at the microphone location or desired range over space and frequency using a two-channel system and a three-channel system. Also the shape of the attenuation contour could be controlled using the proposed method in this paper.

• Periodical: Advanced Engineering Forum (Volume 4)
• Pages: 243-248
• DOI: https://doi.org/10.4028/www.scientific.net/AEF.4.243
• Online since: June 2012
• Authors: Wen Kung Tseng
• Keywords: ∞-Norm, Acoustic Pressure Minimization, Diffuse Fields, Secondary Sources, Three-Channel, Two-Channel

References

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DOI: 10.1121/1.429397

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[7] M. Morari, and E. Zafiriou: Robust Process Control Prentice-Hall, NJ. 1989. Fig. 1 Two-channel feedback control system with two internal model controllers. Fig. 2 Attenuation in decibels as function of space and frequency for a two-channel system with two FIR filters having 64 coefficients and with constraints on amplification not exceeding 20dB at spatial axis from r=0. 1m to r=0. 2m for all frequencies and constraints on robust stability with B1 = B2 =0. 3. Fig. 3 Attenuation in decibels as a function of space and frequency for a three-channel system with FIR filters having 64 coefficients and constraints on robust stability for B1=B2=B3=0. 3 and amplification not to exceed 20dB at the spatial axis from r=0. 1m to r=0. 2m for all the frequencies. (a) (b) Figure 4. Attenuation in decibels as a function of space and frequency for a three-channel system with FIR filters having 64 coefficients without constraints for the different minimization shape represented by a bold rectangular frame. (a) The rectangular frame is narrow in the frequency axis direction and longer in the space axis direction. (b) The rectangular frame is narrow in the space axis direction and longer in the frequency axis direction.