In case of annoyance due to low frequency pure tone noise an anti-noise reduction method can be an effective solution. The cost, in comparison with displacement or replacement, are relative low. In this case the costs amounted to approx. Dfl. 70.000,-(inclusive R&D).If in similar cases larger reductions than 16 dB are needed the adjustment of the speaker blade amplitude should also be automatic controlled. An equalization of the noise production of both noise sources within 0,3 dB for instance can lead to 30 dB reduction.
展开▼
