The simplest explanation of Dynamic range is the difference between the loudest and quietest parts of the music, as measured in decibels, is called the Dynamic Range.
If you need a review of what is a decibel
, click here
However, there is a dilemma here. How do you define what is the quietest part of the music? It seems an easy definition, but if you consider that electronic audio equipment have inherent self noise, then the quietest part of the music is fainter than the self noise produced by the equipment. i.e. the quietest part of the music is below the "noise floor" of the equipment.
So in this case, the dynamic range is the difference between the loudest part and the noise floor, in decibels.
Are you still confused? okay.... let's say you're attending a symphony concert. Sometimes, the orchestra will be playing full blast! Let's consider this the "loudest part of the music." Then in one part of the music, only the flutes can be heard... let's call this the "quietest part of the music." The difference in volume between the solo flute and the whole orchestra playing is the "dynamic range" of the orchestra. But by some bad luck, you're seated to an obnoxious person that's talking on his cell phone. You can't hear the flute solo clearly because your seatmate is making so much "noise." That obnoxious guy, is your "noise floor." So that means, the dynamic range of your music has been reduced. Because now, all you can hear is anywhere between the loudest part of the orchestra playing and the noisy guy talking on his cell phone.
The above illustration illustrates how "noise floor" can rob you of available dynamic range.
In real world scenario, we'd want equipment that gives us the lowest noise floor possible. Because this makes the dynamic range available to us bigger.