ACTIVE SOUND ABSORBER ARRANGEMENT FOR A NON-UNIFORM SOUND FIELD OF A HIGHER ORDER IN A PIPE.

摘要

A system is provided for increasing the frequency range of an active acoustic attenuation system in a duct without increasing cut-off frequency fc of the duct or otherwise splitting or partitioning the duct into separate ducts or chambers. The frequency range is increased above fc to include higher order modes. A plurality of cancelling model sets are provided. Each transverse portion of the acoustic pressure wave has its own set of an adaptive filter model, cancelling speaker, and error microphone. A single input microphone may service all sets.