A PA system, or Public Address System, is used to project sound/music to a large group. These systems are used in sports stadiums, concerts, marching bands, parades, auctions, news conferences, or any situation where a voice or instrument needs to be amplified.
At its simplest form, a PA system includes microphones, mixers, amplifiers, and loudspeakers. How these components are combined is completely up to you depending on your specific needs.
How Does it Work?
Ok, let’s get down and nerdy. Starting from top to bottom there are two popular microphone types used by tech companies. Both rely on a group of coils within the microphone called the diaphragm to interact with sound waves to produce an electrical current. Dynamic Microphones create this current when the diaphragm interacts with surrounding magnets. Condenser Mics have external power sources that produce an electrical charge between the diaphragm and an internal metal plate. The diaphragm in a condenser mic vibrates when struck by sound waves. This results in the coils moving back and forth, changing the distance between it and the metal plate, and creating a sound flow.
From the mic, the sound is put into a mixer. The way the sound travels can vary whether it is digital or analog. Mixers, also known as audio mixers or mixing consoles, vary greatly in size and abilities, but serve the same purpose: to make the sound waves come out of the speakers the way they are intended. Mixers can balance our ensembles, clear the tone of a speaker, add effects, and even combine prerecorded sounds with live performances. We could go on all day about mixers and trust me I have before. For our purposes here though, let’s just stick with the basics. Mixers are a) cool, b) required for PA systems. Portable PA systems like the Megavox 2 have the mixer built into their speaker units. Just because you can’t see them, doesn’t mean they aren’t there. In the shortest explanation possible, sound goes in a mixer through channels and inputs, then makes its way out through, well, outputs.
Those outputs lead us to the speakers.
There are two main speaker types to start. Powered, also known as active speakers, have a built-in amplifier. Think of this as an all-in-one system. All you need is an external power source like a battery, and little understanding of how PA systems work. Unpowered, or passive speakers, need external amps and mixers to power them. They also require cables, cutting back on their portability. No matter which type of speaker you chose, they both convert the electric energy, or the electric current, into motion, or sound waves. This change in energy is achieved by the current within a speaker interacting with coils and magnets, producing pressure and vibration that we know as sound. The type of speaker greatly impacts the sound quality. There are 4 main sub-types of individual speakers:
- Subwoofer – used for the lowest frequencies, never above 300Hz
- Woofer – used for low frequencies, typically below 500Hz
- Mid-Range – used for mid-range frequencies between 200Hz and 3000Hz
- Tweeter – used for higher frequencies between 2000Hz and 20,000Hz
These can be used together, or individually depending on your needs. Most portable systems have a combination of speakers. For example, the Samson Resound VX8.1 has a frequency range of 60Hz-20,000Hz and can be used for essentially any event. Whereas the Anchor Audio Liberty 2 lives in the mid-range sweet spot of 900Hz and is great for speaking, leading rehearsals, or hooking up a metronome.
What does all this mean? Besides the fact I have way too much fun talking about all of this, the biggest take way should be that PA systems can be as easy or difficult as you want. Every pieces of your PA system affects the sound quality, and we haven’t even touched on feedback. No matter how daunting all this seams, tech companies have come a long way in making their products easy to understand, assemble, and use. Whether you’re announcing the winning sow at the state fair or rocking out on stage to a crowd of thousands the perfect system is out there waiting to make you sound amazing, with our selection of audio equipment sold at Band Shoppe, we can help you achieve that goal.