Consideration of complex loudspeaker setups, including phase effects in the frame of environmental noise predictions on the basis of the ISO 9613-2 and the Nord2000.

Authors: Belcher, Daniel; Shabalina, Elena
Publication Date: 17.01.2018

The prediction of noise in the neighborhood of open-air events is becoming more important. An extension of the hitherto procedure for cal- culating predictions regarding two aspects is introduced:

  • Complex summation to account for coher- ence effects
  • Import of detailed data of a sound reinforce- ment system from a system design tool

Commonly available software for calculating environmental noise did not consider complex summation of sound, because typical noise sourcesintrafficorindustryareusuallyincoher- ent. State of the art sound systems with arrays of loudspeakers and subwoofers effectively use coherence in order to achieve high directivity. The possibility to utilize the detailed data of an entire sound reinforcement system via import into environmental noise software enables pre- cise and reliable source modelling for calculat- ing predictions.

Here, two areas with different professionals and tools overlap: sound engineers design sound re- inforcement systems with system design tools and acoustic consultants calculate predictions with software for environmental noise.

The extension for complex summation was im- plemented with two standards for sound propa- gation: Nord2000 as the most advanced and ISO 9613-2 as the widely used. The choice is deter- mined by the particular requirements. Concerning weather conditions in the case of open-air events that only last a few days, spe- cific scenarios should be considered rather than annual averages .