SOUND FIELDS IN A SLIGHTLY DAMPED RECTANGULAR ENCLOSURE UNDER ACTIVE CONTROL

Effectiveness of the global sound field control inside a slightly damped rectangular enclosure by using the potential energy, the squared pressure and the energy density as the cost function is investigated numerically in the present study. A detailed comparison between results obtained using pressure-squared sensing and energy density sensing is presented and the distributions of the zones of quiet are discussed. Three-dimensional visualization of the sound fields confirms that significant localized sound attenuation can be achieved in specific areas even an overall amplification of total potential energy in the enclosure results. The present results also show the occurrence of the detrimental effects and spillovers under the pressure-squared sensing, while they can be removed by using the energy density control. The energy density control results in more uniform sound fields, but is not effective if the error sensor is located between the primary and secondary sound sources. The present finding on producing large quiet zones using a simple system has significant implication for building noise control.