Use

Determine the noise level outdoors at a distance from a point source

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User Inputs

  1. Distance from the point source.
  2. Type of reflection or Source Directivity:
    1. Free space is a source and receiver which are not subject to reflection
    2. Hemispherical is a source or receiver subject to reflection off the ground
    3. Quarterspherical is a source or receiver subject to reflection off the ground and a wall
    4. Corner is a source or receiver subject to reflection off the ground and two adjacent perpendicular walls

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SoundSurfer Input

Sound Power Level (red node)

Algorithm

Hemispherical spreading (free space):

$L_p = L_w - 20logr - 8$

Where:

$L_p$ = Sound Pressure Level, dB re 20 $\mu$ Pa

$L_w$= Sound Power Level, dB re 10$^{-12}$W