Understanding amplitude

- [Speaker] In the previous video, we discussed frequency,…or the cycles per second of a sound wave.…The other important part of measuring a sound…is amplitude or how much the sound wave…fluctuates up and down.…Files with smaller fluctuations will be softer…and bigger fluctuations will be louder.…Looking at this file that I have open in the waveform editor…I can tell just visually that I have three sounds here…and each one is louder than the previous.…Let's play back to confirm this.…(three progressively louder tones)…So the way that we measure amplitude is in decibels…or dB for short and that's a small d and an uppercase B.…

And that's the scale on the vertical axis here.…At the top we have zero dBFS or decibels full scale…and that's as loud as anything can be.…And down at the bottom here we have infinity…or basically silence.…This is why all amplitude is expressed as a negative number,…because you can't actually go above zero…and the scale is married underneath for fluctuations…that go below this line here…