Calculation Mode
Source List
Reference Distance r₀
1.0 m
Reference SPL L₀
80 dB
Target Distance r
10.0 m
Octave Band Sound Pressure Levels
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Total SPL [dB]
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A-weighted LAeq [dBA]
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Distance Correction ΔL [dB]
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WHO Standard Comparison
Formulas
dB Combination (incoherent sources):
$$L_{total} = 10\log_{10}\!\left(\sum_{i} 10^{L_i/10}\right)$$Distance Attenuation (free field, point source):
$$\Delta L = -20\log_{10}\!\left(\frac{r_2}{r_1}\right) \text{ dB}$$A-weighted total:
$$L_{Aeq} = 10\log_{10}\!\left(\sum_{i} 10^{(L_i + A_i)/10}\right)$$A-weighting corrections: 125 Hz: -16.1 dB / 250 Hz: -8.6 dB / 500 Hz: -3.2 dB / 1k Hz: 0 dB / 2k Hz: +1.2 dB / 4k Hz: +1.0 dB / 8k Hz: -1.1 dB
Noise Standards Reference: WHO Environmental Noise Guidelines (2018) — Road traffic: Lden < 53 dBA / Night-time: Lnight < 45 dBA. Japan Environmental Quality Standards (residential): Daytime ≤ 55 dB / Night-time ≤ 45 dB. Occupational noise exposure limit (ISO 1999): 8-hour 85 dBA.