We need to pay attention to the order in which we turn on and off sound equipment. Mixers and computers "pop" on and off, amps "warm" up and down. This means that if the amp is on when you turn on/off a mixer or computer, then the "pop" will be amplified through the speakers, and that could damage them.
So...
When turning on a sound system, turn on the computer and mixer first, then the amp.
When turning off a sound system, turn off the amp first, then the computer and mixer.
