Sound level converter
Convert decibels to sound pressure and back. Decibels are logarithmic, so every 10 dB is ten times the intensity.
That's about the same as normal conversation. That carries about 1× the sound energy of ordinary conversation.
What it means
How loud is that?
Decibels here are dB SPL, referenced to 20 micropascals, the quietest sound a young ear can detect.
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Learn
Three things worth knowing
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+10 dB is twice as loud
Ten decibels is ten times the intensity, but the ear hears it as about double. Three decibels doubles the energy and is barely noticeable.
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Bell’s unit, cut into tenths
Bell Labs measured telephone line losses in bels, named after Alexander Graham Bell. A bel was too coarse, so the decibel, a tenth, became standard.
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Decibels never simply add
Two 80 dB machines together make 83 dB, not 160. Logarithms add by multiplying the underlying energy.
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Background
About sound units
The ear handles a range of a million to one in pressure, so sound is measured on a logarithmic scale: the decibel. Zero dB is the threshold of hearing, not silence.
Because the scale is logarithmic, +10 dB is ten times the intensity and roughly twice as loud to a listener.