What do we gain from the most common unit of sound (Db) being non linear?
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It’s because the scale of the weakest sound to the strongest sound is so big that we used a non linear unit. It’s so that the number won’t have too many zeros in it.
It makes the scale much much smaller. A scale that wouldnt be as precise at low scales but not logartmic would need to be something like 0 – 100,000,000,000,000 (I hope I got the right amount of 0) instead of 0-100 and you dont need the precise numbers at the top as you wont notice a diffrence between 990,000,000,000,000 and 100,000,000,000,000 but you do notice a diffrence between 0 and 1000.
Decibels (dB) are a unit of *relative intensity*, meaning how much louder/brighter/stronger one signal is compared to another.
But mostly what we gain from using dB is a relationship between power and intensity that is close to how humans perceive it. An increase in power by a factor of ten correlates to approximately doubling the perceived intensity/volume.
Amplification and attenuation become addition and subtraction actions rather than multiplicative.
It makes the scale practical.
50 decibels is 10 times louder than 40 decibels, not 1/4 louder.
The logarithmic pattern of decibels describes the actual power produced, not the subjective loudness that you hear. Each increase of 3dB is twice the power, and **each increase of 10dB is 10x the power**.
Using this scale avoids having to use a LOT of zeroes.
if you tried to graph something like noise at a fourth of July party linearly over time, the cars parking, friends whispering to each other, children screaming and playing, and the oohs and aaahs would not even show up on the graph compared to the spikes when a firework went off.
If you want to be able to visually understand the information, logarithmic scales let you do that.
And its just as true as looking at numbers, nobody wants to look at 15 zeroes just to understand what you’re talking about.
In addition to what others have said about keeping scales reasonable, the way our body PERCEIVES sound works on a log scale. The deformation of the hairs in your ear is proportional to the log of the intensity.
The unit is decibels (dB), not Db. Deci is the SI prefix for 1/10 like in decimeters or decilitre. All SI prefixes less than one have lower case letters, All prefixes over 1000 have an upper case prefix, it is 10= deka (da), 100= hecto(h) and 1000= kilo(k) that do not follow the pattern
A bel is a power factor difference of 10
Human perception of sound is not linear, it is logaritmic. It is not as simple as just the sound pressure in dB, there is a frequency dependence look at [https://en.wikipedia.org/wiki/Phon#/media/File:Lindos1.svg](https://en.wikipedia.org/wiki/Phon#/media/File:Lindos1.svg)dB is not preferrect but a lot better than
The usage comes from how signal losses were measured in telegraph and telephone systems. the losses will be in percentage of power per unit of distance and calculating cumulative effect like that in linear scale is cumbersome. In the logaritmic scale if the power drop by 1.5 dB in 1 km then it will drop by 3 dB in 2km, 15 dB in 10 km. If the power starts at 60 dB the power after 10 km is 60-15=45 dB.
Amplification is the addition of an amplifier that has the output at 1000x the power of the input signal has an amplification of 30dB, the mean if we input the 45dB signal to it you put is 45-30=75 dB
Division in linear scale becomes substation in logaritmic scale and multiplication in linear scale becomes addition is logaritmic scale
Because a factor of 1bel was impractical larger measuring change 1/10 bel was a lot more practical and the result is dB is most of the time thereated as the base unit. Other prefixes are seldom use so five one-thousandths of a bel is normally written as 0.05dB not 5 mB (milibel)
The loudest sound possible in earths atmosphere is 194dB.
This is about 20,000,000,000,000,000,000 times as loud as 1dB.
Pretty quickly you just see “large number of zeros”. And humans don’t perceive power that way. If you double the actual volume, humans won’t hear something twice as loud. You have to make it more like 10x as loud for humans to think it’s doubled in volume.
While a logarithmic scale is harder to work with, it’s actually more intuitive. You can know that motorcycles and lawnmowers are at around 100, while vacuum cleaners are more like 80. But motorcycles and lawnmowers being 10,000,000,000 while vacuum cleaners are only 100,000,000 is a lot less clear.
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