# SIL - Speech Interference Levels

## Approximate speech interference levels

Speech Interference Levels - SIL - are arithmetic average sound pressure levels at the 500, 1000 and 2000 Hz center frequencies - and a measure of the degree to which background noise interferes with speech.

• 1 ft = 0.3048 m

The diagram above indicates the SIL and the distance at which a person would have talk in a normal, raised, very loud or shouting voice to be understood.

### Example - Use of Voice with Background Noise

If the background noise - sound pressure level - is 75 dB and the distance between two persons is 6 m - they have to raise their voice to more than a very load level according the diagram above.

## Related Topics

• Acoustics - Room acoustics and acoustic properties - decibel A, B and C - Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation

## Related Documents

• Daily Noise Dose Level - Daily noise dose when exposed in periods with different noise levels
• EPA Protective Noise Levels - The noise level should not exceed certain values to protect public health and welfare
• Comparing Noise Criteria - Comparing Noise Criteria - Noise Criterion (NC, NCB, RNC), Noise Rating (NR) and dB(A)
• Sound Level - Online Calculator - Convert between sound level, sound pressure and sound intensity
• Outdoor Ambient Sound Levels - Outdoor ambient sound level (dBA) in rural and urban business and industrial environments with or without limited traffic
• Telephone use in Noisy Areas - Use of telephone in noisy areas - satisfactory, difficult and impossible noise levels
• Sound Power - Sound Power Level from common sources like fans, jet engines, cars, humans and more ..
• Sound Pressure - Sound Pressure is the force of sound on a surface area perpendicular to the direction of sound
• Decibel - Decibel is a logarithmic unit used to describe the ratio of a signal level - like power, sound pressure, voltage, intensity etc. to a reference level

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