Yeah "2000 dB" is a reasonable number for something being really loud
So this is one of those bits of physics that isn't really intuitive.
Until you put the pieces together and have that ah ha! moment.
You've maybe seen that demonstration showing what transverse and longitudinal waves look like with a slinky. Transverse you wave it side to side. Longitudinal you push it back and forth so it bunches up.
Maybe you can visualise the cone of a speaker moving back and forth and see that resulting in a wave.
Maybe you can visualise that expanding out in a sphere.
We talk about high and low points on waves, because it's familiar to visualise them like ripples on water. With sound waves, which are longitudinal, it's pressure though. Bands of high and low pressure. (Think about the slinky coils getting closer together and further apart)
When you visualise it as a ring of high pressure moving out from a central point you can see it starting to look pretty much identical to an explosion.
The higher the 'peak' of the wave the more pressure.
Added fun: this is true regardless of what the sound is moving through. You're making atoms bunch up, then having them spring back apart. Which makes the number of instruments that work by hitting something make more sense. Whether that's a gong, or a piano, you're still sending that ring of contacting and expanding atoms out.
