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SpectraSim Documentation
Parameter · 07 Run Settings

Outlet height

acoustics.radiated_spl.outlet_height Unit: m Step 07 · Run Settings

The height of the centre of the outlet orifice above the reflecting ground. It sets the automatic microphone height and the geometric check of the measurement position.

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Theory

Because the ground is represented by the directivity factor Q=2Q = 2, the level does not depend on the heights. The heights define the position:

  • the automatic microphone height is the outlet height, but not below 0.2 m, equation (1);
  • the microphone may not lie farther above or below the outlet than the distance dd, equation (2).

Equations

hr=max⁡(hs, 0.2 m)(microphone height on auto)h_r = \max(h_s,\ 0.2\ \mathrm{m}) \quad \text{(microphone height on auto)}
(1)
∣hr−hs∣≤d\lvert h_r - h_s\rvert \le d
(2)
wheremeaningunit
hsh_sOutlet height (this setting)m
hrh_rMicrophone heightm
ddMicrophone distancem

Default and rule

Default
0.2 m
Rule

0.2 m.

Source

ISO 5130 (stationary road vehicles, survey method, 6.3.1): microphone at the height of the orifice, but not lower than 0.2 m.

Valid range 0 to 20 m

Values

0 to 20 m.