PA Systems are not that complicated. Most have similar components.
They usually have a mixing board. The mixing board allows someone to control the volume of every microphone separately. So if one person is too loud or too quite, that person’s microphone can be adjusted. Almost anything can be plugged into the mixing board: microphones, instruments, computers, and recording devices. The mixing board is the control center.
Amplifiers are another component that is necessary in all PA Systems. When a microphone or guitar sends a signal to the mixing board, it is just a signal. Without an amplifier, no one would be able to hear the guitar or microphone.
Sometimes a mixer board will have an amp build into it. Sometimes the amplifiers are separate and sometimes the amplifiers are inside the speaker cabinets. You have to be careful what you can hook together. If the mixing board has an amp built in, the you do not want to plug it into speakers that have an amplifier in the cabinets. Here is how to know what to do - anytime there is an amplifier, the wire you plug into the amp cannot have power in it (Or already been amplified).
Case 1: The mixing board does not have power. (This is referred to as passive). You need an amp to amplify the signal before it gets to the speakers. You can either plug into an amplifier and then into the speaker cabinet or plug into a speaker cabinet that has an amplifier built in.
Case 2: The mixing board has power because it has an amplifier built in. In this case, you do not want to plug into an amp and you do not want to plug into speakers that have an amp built in. Your only option is to plug directly into speakers that do not have an amp built in.
The above diagram has a passive mixing board and active speakers. Active speakers mean that the speakers have amplifiers inside of them.
The above diagram has a passive mixing board (No power) and passive speakers (No power in the speakers). So, this system needs amplifiers. A signal goes out of the mixing board and to the amplifiers where it is boosted. The boosted signal then goes to the speakers.
One amplifier can be used to run one speaker or many speakers.
If you use separate amplifiers it is good to learn about Ohms. When you add more speakers, the amp has to work harder. You have to make sure that the amp can handle the number of speakers you plug into it. At The Youth Division, we try to use simple systems that do not involve separate amplifiers.
Amplifiers can look different. Here is a stack of four Crown amplifiers.
Amplifiers require a lot of power. Each amp should have its own outlet and breaker. This can be difficult to find. Often churches will have just one outlet to run everything.
Whichever system you use, this diagram shows the necessary components that make up a sound system.
Self-control is important when running a PA System. Sometimes teens like to crank up the volume too loud. The result can be expensive when speakers get blown. Remember that PA Systems are expensive and they do not belong to you. Be careful with them.
