As the number of out-door events in urban areas is increasing, so are the accompanied noise challenges and therefore the need for accurate noise predictions. A new easy method for noise predictions with sound systems for out-door events, that uses data of actual system designs and applies complex summation, is introduced and shown.
The system data including all electronic filters is simply imported with a system design file (d&b’s ArrayCalc simulation software). This procedure eliminates any friction losses, because it spares the repeated process of re-modeling a sound system in the noise prediction software and therefore ensures that the prediction is done with the actual and current state of the system design. It also is the only sensible way to include the specific electronic filters of a sound system (also IIR, FIR).
Noise prediction software did not consider complex summation simply because noise sources are assumed not to be correlated with each other (e.g. in traffic and industry). This is where sound systems are quite different, because the signals sent to the loudspeakers at different positions are usually always correlated. Furthermore, modern sound system even use coherence effects to influence directivity (e.g. arrays).
The sound propagation calculation was extended for complex summation and the method of inporting system data was implemented in SoundPLAN software and in NoizCalc – a separate tool from d&b for free download.