Design of undirectional sources for active control of noise in ducts

Vesa Välimäki, Seppo Uosukainen, Paulo Diniz

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


    Unidirectional sound sources can be used in the implementation of forward active noise control (ANC) systems for ducts, where the anti-sound needs to propagate downstream but it is also desirable that no upstream radiation occurs. This paper discusses a new approach to the design of a unidirectional source. A digital signal processing system involving adaptive filtering is proposed for automatic design of a unidirectional source The automatic calibiation of the system can be executed in 3 phases: 1) calibration of the impulse responses from the actuators to the microphones, 2) calibration of unidirectionality, and 3) calibration of the error path from the unidirectional source to the error detetector. After these procedures, the ANC operation can start. In this paper, a fixed target FIR filter for the design stage of unidirectional two-element sources is proposed. The new method is compared with an earlier one proposed by the authors. The directivity of the source can be improved at almost all frequencies, and the obtainable attenuation is improved at the frequency range which overlaps with the passband of the target filter.
    Original languageEnglish
    Title of host publication6th International Congress on Sound and Vibration (ICSV6)
    Place of PublicationLyngby
    PublisherInternational Institute of Acoustics and Vibration (IIAV)
    Pages1627 - 1634
    ISBN (Print) 8798745786
    Publication statusPublished - 1999
    MoE publication typeB3 Non-refereed article in conference proceedings
    Event6th International Congress on Sound and Vibration, ICSV6 - Copenhagen, Denmark
    Duration: 5 Jul 19998 Jul 1999


    Conference6th International Congress on Sound and Vibration, ICSV6


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