Recently, I was asked by my best friend to set up the PA system for his birthday party, and as an obedient friend, I acquiesced to his request. My long years of experience as a sound engineer in many gigs and shows had taught me more about PA systems, and for this reason, I thought I was in a better position to help my friend at that time.
The PA system, of course, consists of many components. So, if you intend to master the PA system, you need to be cognizant of these components and their functions in a PA system. Moreover, there are also various types of PA systems. So, if you want to be a sound engineer, you need to familiarize yourself with multiple types of PA systems.
Main Components of a PA System
The main components of a PA system include the speakers, amplifiers, audio mixer, speaker processor, microphones, effects, DI box, cables, and other accessories. Reading through this post, you can familiarize yourself with each of these components:
1) Main Speakers
The main speakers are crucial to a PA system, without which, the system will never be a PA system. They produce a significant amount of the PA system’s sound. Their placement, of course, in a venue, is crucial to the PA system’s coverage area.
Besides, it will help to mount them on stands or top of the subwoofers. Their sizes are enormous and range between 10″ to 15″. They also have a smaller tweeter on top of the woofer.
Subwoofers are bigger than the main speakers, for they got a particular job of producing the lower frequencies, and the sound they make fills out the ear. The sizes of subwoofers range from 15′ to 20′. Moreover, you can see dual subs that are only 12′.
A crossover unit separates the sound of the main speakers and the subwoofers. This crossover unit is typically rack-mounted. It separates the signal that courses through it according to frequency. Thus, it sends the higher frequencies to the mains and the lower frequencies to the specific subwoofers. Given that fact, you would need a crossover unit; besides, you need to choose the right crossover frequency for the venue.
3) Stage Monitors
The typical stage monitors are set on the ground at a tilted angle towards the performers. You would see the stage monitors near the performers to enable them to hear themselves when they perform. The audio signals coming out of the monitors are not the same as the audio signals from the mains and subs. However, you will sometimes see some main speakers that serve as stage monitors.
The microphone is an essential component of a PA system. It is the reason why the PA system is called a public address system, without which you can never address the public. It converts sound energy into electrical energy. It is the transducer that catches the sound waves and turns them into electrical audio signals.
The microphone achieves this transduction in many ways. Yet, the typical way is via electromagnetism. One example of mics that make use of electromagnetism is the dynamic microphone. The dynamic microphone is the typical microphone you will see in use, and it uses electromagnetism.
PA systems make use of either passive or active speakers. The active speakers come with an internal amplifier, while the passive speakers don’t have a built-in amplifier. They require an external amplifier to boost the line-level signals to a higher level. Therefore, if you have passive speakers, you will rely heavily on the amplifiers to raise the line-level signals.
If you would shop around for an amplifier, you will discover that the price range of amplifiers is high, which means they are expensive. Well, they must be costly because they play a critical role in the PA system.
There are instances when the mixers come with built-in amplifiers. Such mixers are called “power mixers” or “all-in-one mixers.” Having such a mixer would surely simplify your PA setup.
If you don’t have mixers with built-in amps, you need separate cables to transmit the mixer’s and the amplifier’s audio signals.
6) Mixing Console
The mixing console is the device that you would use to combine sounds from different audio sources. As such, there are very important to the PA system. If setting up the PA system is like preparing for war, the mixing console would serve as the main headquarters where the tactics and strategies are done.
The typical mixing board comes with many channels ranging from 8 to 32 channels. It also has main stereo outputs, plus multiple aux outputs. It also has a few subgroups.
The mixing board is also responsible for routing and changing the audio signals’ volume level, the timbre, and even the dynamics of various audio signals. The cables that go into the mixers are usually TRS and XLR cables.
The mixer can also supply phantom power for the microphones. It can pan control for every channel. It can also monitor mixes and channel signals to the stage monitors. Moreover, the typical mixing consoles come with right and left outputs. It also comes with individual outputs called “Aux sends.”
The different components of the PA system are not connected wirelessly. Hence, you will need cables to join them. The most common cable types used to connect the different PA system components are the XLR, TRS, and Speakon. The amplifiers and mixers, for example, come with TRS and XLR outputs and inputs. Some amplifiers may have banana cabling, which is one form of RCA outputs.
The use of the right cables is critical to the overall setup of the PA system. If you use the wrong cables and connectors, the components may not function well or get damaged in the worst case.
Microphones mostly use XLR cables with three-pins. Yet, you will also find some mics using 1/4″ TRS jacks. Some others even make use of 1/8″ jacks.
If you look closely at the PA system, you will notice the faders, which are the sliding controls. These fader controls organize every bus assignment and level of each channel. The faders also come with solo and mute buttons. These buttons partition the activities on every channel.
Faders can also be digital or analog. With analog fader, you can directly control the resistance to the source. It can also be digital. Digital faders can control the digital signal processor numerically. Many call the digital fader a virtual fader, for they are viewable on the audio workstation’s screen.
The layouts of most PAs are almost similar to each other. Thus, if you get the hang of the use of the simple PAs, you can also transition to the more complicated PAs without much problem. Furthermore, the prices of Public Address Systems range from $400 to $1,000 or even more.
You can also include effects in your PA system, though including them, is optional. Moreover, you can find modern mixers equipped with onboard effects. However, many prefer to have outboard effects in their PA systems. These outboard effects are stand-alone units, and examples of these outboard effects are compression, reverb, gates, delay, and equalizers.
Once you’ve known the essential components of a PA system is the first step in setting up a workable PA system. Operating the PA system necessitates another level of knowledge, and it can be frustrating sometimes but very rewarding most of the time. The operation of the PA system can be straightforward and trite, or it can be not very easy, especially if you are involved in large scale productions like big concerts.
If you intend to purchase a new PA system or want to dip your hands into the audio business, you need to be familiar with these different components and their functions. It will also help to hire a good sound engineer to manage your system sound mixing and routing.