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What is a PA System?

Public Address systems, or PA systems, are used to broadcast announcements over a designated area and are comprised of loudspeakers and other audio equipment.
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  • Originally Written By: Jessica Ellis
  • Revised By: G. Wiesen
  • Edited By: Bronwyn Harris
  • Last Modified Date: 23 March 2014
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A Public Address (PA) system is a collection of audio equipment that allows broadcasts over a designated area. Often found in schools and office buildings, PA systems can be used for general announcements or emergency information, providing a simple way to get information out quickly. PA systems can be basic or advanced, and people can customize them to fit a variety of needs. There are even personal models that can be less expensive, but allow for a much shorter range.

General Systems

Basic PA systems are comprised of loudspeakers placed in convenient locations around a broadcasting area, an amplifier to increase the sound, and a mixer that adjusts audio levels. The user speaks into a microphone, and the sound is transmitted through connected cables, or a wireless system, out through the speakers. Some systems also include microphones or intercoms near the speaker locations, allowing the listener to reply to the central location. These responses are not broadcast to the entire system, however, but only to the main user area.

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Functions for Schools

Many schools use a PA system to broadcast daily announcements about school activities, and often let students use it to give reports or announce special events. The device can also function as an emergency warning system. In case of fires, earthquakes or other natural disasters, administrators often use a PA system to instruct students and teachers on where to go and how to respond. With the tragic rise in school shootings in the early 21st Century, many schools have installed special emergency warnings through these systems to alert students and staff about a violent attack on the campus.

Performance Systems

Many venues use a large-scale PA system to amplify sound for concerts or theater productions. Often called Sound Reinforcement (SR) systems, these versions are much more complex than the simple ones found in schools and offices. SR systems frequently use a dual broadcast setup, projecting the sound from the stage into the audience, and also into backstage monitors that keep any off-stage personnel informed of what is happening. This type of PA system may have dozens of microphones feeding into it, and may need several technicians to operate and maintain it correctly.

Personal Units and Custom Devices

While a simple and portable PA system is often fairly expensive, it can provide a speaker with some options for addressing a crowd of people. This type of public announcement hardware provides someone with extremely limited broadcasting range, often including only a single speaker, but still serves to amplify the user's voice. More advanced versions increase in price considerably, especially with numerous cords, wireless hubs, and adaptors that may be required. This all depends, however, on what a person or business needs in terms of PA system hardware and installation.

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Discuss this Article

perspective
Post 6

@TunaLine: Powerwerks PW100T. Amazing pa system starter buy. My advice from experience is to stay away from the all in one kits like those mentioned (they are good for PA, not sound reinforcement). I would also suggest the Harbinger series, however the company is owned by Guitar Center (I loathe Guitar Center with every fiber of my being in existence).

I own a pw100t and I love it. I think it was $230 with tax included, so it's not really that big of an investment. You can add subs and monitors as you go (I don't think the ones mentioned add on, which is another reason why not to buy them for a band whose fan base only grows). I play acoustic guitar through a samson r21s mic and sing through an sm58, and the amp sounds better than I expected it to.

First impressions of the PW100t were "Oh wow, a knockoff fish stick, and 800 bucks off the price? Yeah. Watch it sound like crap." I played it for maybe five minutes in the store and put it on layaway that day. I haven't had it too too long, but it's been through a few coffee houses and dive bars since.

Powerwerks also makes other models of PAs, mixers, subs and monitors, so you should check them out as a brand some time. You might find what you like with their label on it. Most of the products I've seen don't seem like a huge chunk of your pocket is lost.

Lastly, PA systems mixers and all that Hz feedback mumbo jumbo used to confuse me. The mixer onboard the pw100t is about as user friendly as you can get, gets loud for the price range, and the quality of the product blew me away. I will definitely add a monitor and subs soon to my pw100t just to make me louder and louder as needed at a particular venue, and because of my expectations, it will probably be a powerwerks logo.

But if you are set on one of those three, do not let me turn you away from it, by any means. I'm just letting you know the route I took. Have fun. And in the words of Todd Rundgren, "I don't wanna work, I wanna bang on the drum all day."

TunaLine
Post 4

So I'm trying to choose a good PA system/amplifier for my band, and I'm stuck on which one to go for. I mean, it's a big investment, so I don't want to back the wrong horse, right?

I've narrowed it down to a few, and I'm stuck deciding between a Yorkville wireless PA system, a Soundtech PA system, a NADY PA system and a JBL PA system.

Which one should I go for? I really want a good one, since my band plays a lot of different venues with different acoustics.

Of course, I'd rather not break the bank either, but if it comes down to it, I would prefer to have a better performing system that's more expensive than a cheaper, but acoustically worthless, system.

Any audio engineers (or others) got advice for me?

LittleMan
Post 3

Whenever I think of PA audio systems, two things come to mind -- the morning announcements in the movie "Grease", with the little chime that the secretary played, and the announcements that Nurse Ratchet used to make over the PA in "One Flew Over the Cuckoo's Nest".

Both excellent examples of how something as ordinary as an audio PA system can be used in a movie to create two very different effects.

closerfan12
Post 2

I always remember the old PA sound system at my elementary school being so fuzzy and unclear. I don't know if if was just the wiring or if the school had gone with a cut-rate system, but you could hardly ever hear what people were saying over that thing.

I remember it being a running joke among the teachers, too -- the best you could do was guess at what the PA was saying, and then send a kid to the office to find out if you were right.

StraightLine
Post 1

Music has helped drive some wonderful innovations in PA systems and speaker technology. For instance, the Leslie Cabinet rotated at varying speeds, sending the sound in all directions of the room (rather than simply in the direction the speaker was facing). A lot of guitar players in the psychedelic rock era, such as George Harrison and Jimi Hendrix, used these speakers to create the sensation that their guitar sounds were careening around the room, no doubt adding to the psychedelic experience of the shows.

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