Pop! Thump! Boom!
It happens every time you turn your sound system on or off, a loud pop or thump. Not only does it sound bad, it can damage your speakers. So why does this happen and how can you prevent it? Often, this happens when you turn equipment on or off all at once instead of in the proper sequence.
To keep things simple, your speaker amplifiers (or powered speakers) should be the last thing turned on and the first thing turned off.
Here’s why. Gear that sends signals to your speakers (a mixer for example) generally sends a very small power spike down the audio line when powered on or off. While it’s not very powerful, the job of amplifiers or powered speakers is to weak signals into powerful signals. The result is that when you turn off your mixer the amplifiers turn that tiny power spike into a big “THUMP” at your speaker.
Some gear has a “soft” power down, which means that you don’t have to worry about this issue. For the rest of us there are a few things we can do.
Establish a Power Up/Down Sequence. This can just be a small note, indicating in what order you should turn things on and off. Train your volunteers to follow this procedure.
Use a power sequencer. Several companies make units that will power the whole system up and down in a proper order with just one switch. This is a great way to simplify and protect your sound system.