I have been playing many instruments for a decade and now I kinda understand em real well , but this abstract is not about me bragging about how many instruments I can play but it is about wtf is a DB, I mean being a working underpaid musician for years I have never been into the core concepts of music and acoustics, it was only few years back when I got Into mixing and mastering that I went into deep mathematical and scientific journey around the ONE AND ONLY — db, and since then it changed a lot inside me, so let’s dig deep into what the heck is Db and why you have to know about it, so let me tell you it totally doesn’t even matter if your an amateur or a pro if you don’t know about it you are missing out a lot.
So when we talk about volume we talk about the loudness (Db) which is quite obvious because volume refers to the volume of the sound being spread, more volume the more spread it will have and hence you can hear the sound frequencies from a long distance, okkk so to make it super simple think about a big tub of water which has a small hole , I mean whatever is the size of the tub , the flow of the water will depend on the hole size and the water will flow out as long as the tub is full or reach below the hole level , now apply the same analogy with the sound , when you turn the volume up you are increasing the surface area of the hole so that more sound flows , the more area the hole has the more sound will follow , this analogy fits with volume the more you crank it up the more you can hear them and just like water hole gets bigger and bigger the water pressure will increase , the same goes with volume the SPL ie the sound pressure level will increase .
Now keep the above mentioned analogy in your mind and fit it with Db, decibel is a term that is used a lot in electrical and electronic engineering , Db is a log scale that means it is not a linear function hence it is an exponential function which defines the SPL and POWER of sound waves.
The Db has a formula and it is usually a measure of very large quantities in a form which can be easily measured , the master level Db meter is kept below -6db to provide more head room to the mixing and the mastering engineer, so when you look at the Db on the channels these are the measurement of the sound pressure and how much power that an acoustic setup is delivering.
The formula of Db used in your DAWs are based upon the calculation of the lowest hearing range to the highest hearing range and these ranges are the measurement of INTENSITY so they have W/m2 unit.
These min and maximum threshold values are the SOUND PRESSURE LEVEL VALUES that our ear can process, these values are fed into a log scale to get the Db value, Db value are always in reference with 2 values (REAL/REFERENCE) usually of power, intensity, pressure and volt units. (Taking one unit at a time).
I know it is kinda geeky but as soon as you will see the formula of Db you can easily understand that it is a measuring system that is used across multiple domains, the wifi in your home has a Db value , the radio signals have a certain measured Db value and these values are the most vital measuring unit in Digital signal and analog signal processing.