So the idea of using ratios helps make the 'unit of measurement' explicit.

Why bother with this? it becomes clearer when we say the same thing in a different way: any quantitative measurement, absolute or relative, implicitly has some underlying 'reference' measurement, which is the 'unit' of measurement. Example: 100 degrees Celsius? That's a ratio where you have 100 times more than one unit of degrees Celsius. Step 1: Any measurement, absolute or relative, can technically be re-interpreted as a ratio compared to some reference value. Not how decibels were conceived as I understand, but good for learning:

So now we can make up a new unit called dB BB (bottle B) and say 'bottle A has 3dB(BB)' or something. So 6db SPL would be 80 micropascals which is really completely inaudible. Eg: dB SPL (sound pressure level) are relative to 20 micropascals (a measure of pressure). Which is why there are many types of decibels. The final piece of the puzzle is that you need a reference value. Imagine you had to say 'oh increase the gain by 10000000 units' vs 'increase the gain 70dbs'. Why use decibels instead of a linear value like kgs, pounds, etc? Well, the thing with sound is that it would be a mess to use a linear value since it can go from tiny values to extreme huge values. So doubling is increasing by 3dbs, quadrupling 6dbs, etc. The other thing to understand is that decibels are logarithmic and not linear. So you have a base reference (bottle B) and the actual value (bottle A). The basic idea is 'bottle A contains double the water compared to bottle B'. Like David said, a decibel is only a unit of relative value. I am thoroughly confused and lack any sort of practical understanding of these terms. And another source mentioned noise in dbA unit. What does this mean? In comparison to DAWs, this would be deafening and yet I am aware that helicopters emit over 150dB.

For instance, I found that CPU fans have an approximate <21dB sound output. In life, I hear the term decibel refer to all sorts of things. A clear, (not necessarily) concise explanation would be very helpful.Ģ. I have tried and failed to understand why it is in negative as it makes no practical sense to me. From a DAW point of view, we are all accustomed to seeing a meter starting all the way for -60dB and going all the way up to 6dB mostly). However, one term that still eludes my understanding is the very unit of sound level: Decibel (dB). I have been involved in music production and composition for almost 2 years now and have a very basic understanding of the essential terms one comes across in this field, in general.

Decibel reference scale