Speech interference level

Speech Interference Level (SIL) is an acoustical parameter calculated from sound pressure levels measured in octave bands. It is used to characterize a noise signal in the frequency range where the human ear has its highest sensitivity.[1]

The Speech Interference Level is calculated as the arithmetic mean of unweighted sound pressure levels in three or four octave bands in the 500 Hz - 4 kHz frequency range.[2]

Variants of Speech Interference Level[3]
PSILArithmetic mean of 500 Hz, 1 kHz, and 2 kHz octave bands
SIL3Arithmetic mean of 1 kHz, 2 kHz, and 4 kHz octave bands
SIL4Arithmetic mean of 500 Hz, 1 kHz, 2 kHz, and 4 kHz octave bands

References

  1. ↑ Karl D. Kryter (2023). The Handbook of Hearing and the Effects of Noise: Physiology, Psychology, and Public Health. Leiden, Netherlands: Brill Publishers. ISBN 9789004653443.
  2. ↑ Criteria for Evaluating Room Noise (standard). Melville, New York: American National Standards Institute. 2008. ANSI S12.2-2008.
  3. ↑ Acoustics — Description, measurement and assessment of environmental noise — Part 1: Basic quantities and assessment procedures (standard). Geneva, Switzerland: International Organization for Standardization. 2016. ISO 1996-1:2016. Retrieved 21 March 2026.