The Oshima Maru is a 226-gross-ton training ship equipped with one 1300 Ps, 370r.p.m. diesel engine. In this ship, various structural countermeasures against vibration and noise were taken. However, unpleasant low-frequency sound from the engine room persisted in the mess hall where crews take their breaks. The main engine room, located on the lower deck, is adjacent to and partially below the mess hall. Conventional solutions for that noise are also subject to considerable structurally variation. Active noise control, ANC, is capable of providing a universal solution. In order to apply ANC, we investigated the sound field in the mess hall using complex intensity analyses and multiple coherence function. From these results, we selected the reference signals suitable for ANC and considered constructing the active control system using multichannel filtered-x LMS algorithm of the ship interior noise.
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