SPL explained - Sound Advice

In this video, Alejandro explains what Sound Pressure level is and why understanding this can help when making a decision to purchase a powered loudspeaker.
Sound pressure level. What is this?
One of the most relevant, sound related numerical specifications
when choosing an active loudspeaker is the sound pressure level or SPL value.
This number is expressed in decibels,
and indicates how loud a system can reproduce sound at a given distance.
At the receiving end, which is our ears,
Our auditory system has a dynamic range of about 90 dB,
ranging from a 30 dB whisper to an airplane taking off at 120 dB.
Beyond such levels sound pressure starts to create physical pain.
Now, how does Power or Watts relate to SPL?
A driver requires electrical power to move its voice coil
so that its attached diaphragm can move like a piston and create sound waves.
Now, you understand that to create sound, you need energy.
If a system consumes little energy and provides high SPL, it is efficient.
QSC Loudspeakers are designed to be very efficient.
As an example, a PA system consisting of two K12.2 over two KS212C subwoofers
will draw 11 amps at 120V.
This means you can run an entire rig on a single common household power circuit.