Required Voice Level at Distance

Distance and perception of voice. Calculates required voice level at various distances based on the inverse square law (6 dB decrease per distance doubling).

Distance (ft)Distance (m)Normal Voice (dB)Raised Voice (dB)Very Loud Voice (dB)Shouting Voice (dB)
10.370768288
30.960667278
61.854606672
123.748546066
247.342485460

Voice Level Classifications

  • Normal Voice: ~70 dB PSIL at 1 ft (0.3 m)
  • Raised Voice: ~76 dB PSIL at 1 ft (0.3 m)
  • Very Loud Voice: ~82 dB PSIL at 1 ft (0.3 m)
  • Shouting Voice: ~88 dB PSIL at 1 ft (0.3 m)

Key Principle

For every doubling of distance from the noise source, the sound pressure level decreases by 6 decibels (inverse square law).

Background Noise Guidelines

  • Social Settings (1-4 m): Background noise should not exceed 55-60 dBA
  • Outdoor Recreation (5-10 m): Background noise should not exceed 45-55 dBA

PSIL Formula

PSIL (Preferred Speech Interference Level) = 1/3 (Lp500 + Lp1000 + Lp2000)

Or from dBA: PSIL = Lp (dBA) - 7

Required Voice Level at Distance | MEPKit Engineering Tools | MEPKit