FullCalculator

Noise Reduction Calculator

Distance Attenuation

Calculate noise reduction from distance

Sound Barrier/Wall

Calculate noise reduction from a barrier or wall

Combine Sound Sources

Calculate total dB from multiple noise sources

Formula

Distance: dB₂ = dB₁ - 20×log₁₀(d₂/d₁) | Combine: dBtotal = 10×log₁₀(10^(dB₁/10) + 10^(dB₂/10))

Frequently Asked Questions

How does distance affect sound level?
Sound level drops by 6 dB each time you double the distance from the source (outdoors, point source). So an 80 dB noise at 10 feet becomes 74 dB at 20 feet, 68 dB at 40 feet, and 62 dB at 80 feet.
How much noise reduction do I need?
Every 10 dB reduction sounds roughly half as loud. A 20 dB reduction makes noise seem about 1/4 as loud. For comfortable indoor living, aim for 40-50 dB from exterior noise sources (STC 45+). For home theaters, STC 55+ is recommended.
What are common noise levels?
Whisper: 30 dB, Normal conversation: 60 dB, Vacuum cleaner: 70 dB, Lawn mower: 85-90 dB, Concert: 100-115 dB, Jet engine at 100 ft: 130 dB. Prolonged exposure above 85 dB can cause hearing damage.

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