Microsoft made a -23 decibel room, but how does that work exactly? Once something hits 0 decibels how exactly can we measure it getting more quiet than that?
In: 24
Decibels are a unit describing the ratio of two values. When used for amplifiers or attenuators this ratio is output to input. When used to describe a single value, like loudness, the ratio is between the measured value and a fixed reference value.
When describing sound levels that reference value is a sound pressure of 20 microPascals in air (because sound is just air pressure)
Decibels are a logarithmic representation of the measured air pressure divided by this reference air pressure. Specifically 10*log(measured pressure/reference pressure).
The way logarithms work , if the measured pressure is bigger than the reference you get a positive result. If it’s smaller than the reference you get a negative result, and if it’s exactly the same, you get zero decibels.
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