Affordable PA System Buying Guide

Views 1 Like Comments Comment
Like if this guide is helpful
Affordable PA System Buying Guide

PA or Public Address systems are used to amplify, reinforce and broadcast sound. A PA system is a crucial component of any live performance. Musicians and artists that play smaller venues often prefer to own a PA system, lest the venue not have its own in-house system. PA systems can vary wildly in price and performance depending on the output power and system capabilities. A good PA system not only amplifies sound, but also allows artists to emphasise particular sounds.

About PA Systems

The purpose of a PA system is to amplify and distribute sound. PA systems are used in a variety of public settings, from live concerts to libraries. PA system is a broad term that refers to multiple instruments, including, but not limited to, mixing consoles, amplifiers, and loudspeakers. PA systems are sometimes also called Sound Reinforcement (RA) systems, although this term is used only in relation to live music performances.
Depending on the use, PA systems can be as simple as a microphone and loudspeaker assembly, or complex arrangements involving mixers, amplifiers, loudspeakers, and routers. The simplest possible PA system consists of at least one microphone, loudspeaker, and amplifier (either built into the loudspeaker or external). Such systems suffice in small venues, but larger venues such as airports, schools, and stadiums require more complex assemblies. These may include complicated monitoring and sound reinforcement systems with dozens of loudspeakers, mixers, amplifiers, and microphones.

Buying an Affordable PA System

Any good PA system would include a microphone, an amplifier, one or more speakers, a mixer, and preferably, a pair of headphones for monitoring purposes. Additional equipment such as power backup, quality cables and wiring, stage box, etc. may be required in certain circumstances.
A simple PA system assembly consists of a microphone plugged into a mixer. Output from the mixer is sent to a power amplifier, which ultimately connects to the speaker to reproduce sound. The mixer itself may be connected to effects boxes/pedals and foldback or stage monitors. The ultimate aim of the PA system is to broadcast as accurate a reproduction of the original sound as possible.

Types of PA Systems

PA Systems can be either active or passive. A passive PA system requires an external power amplifier, while an active system has an amplifier built into the loudspeaker. The performance of passive systems is generally superior to active systems, but they also cost more as one has to purchase amplifiers and speakers separately.

Affordable PA System Microphones

The microphone is the first instrument in any PA system assembly. The microphone captures acoustic sound waves and converts them into electrical signals, which can then be transmitted to the loudspeaker. Microphones may be either wireless or wired. They may be either handheld or stand mounted. Broadly speaking, microphones used in PA systems can be of the following types:

Condenser

Condenser microphones consist of capacitors that change capacitance when struck by sound waves. For this reason, they are also called capacitors. Condenser microphones are usually used for broadcasting vocals in a PA system. They require external power, which limits their functionality in live situations.

Dynamic

A dynamic microphone is made up of a thin diaphragm connected to a coil of wire suspended between two magnets. When sound waves strike the diaphragm, the coil starts moving between the magnets, producing an electrical current. Dynamic microphones, consequently, do not require an external power source. They are extremely affordable and the microphone of choice for use in PA systems.

Other types of microphones such as ribbon or crystal/piezoelectric microphones are usually used in studio settings and rarely find any application in live performances. Dynamic microphones are recommended for use in PA systems as they have a large dynamic range, good sound reproduction and are affordable.

Affordable PA System Mixers

Sound captured by a microphone is sent to a mixer. The purpose of a mixer is to balance and correct input sound. It can also apply effects and filters to the sound if necessary. The output sound can then be sent to a monitoring system and amplifiers.
Mixers can be broadly classified into the following three categories:

Analogue

An analogue mixer utilises the analogue sound waves coming from a microphone. The sound waves are broken into various frequencies which can then be amplified, reduced and modified with effects. Analogue mixers have a warmer tone and offer greater control to the user. On larger mixers, however, analogue controls can become extremely complicated.

Digital

A digital mixer first converts analogue signals coming from a microphone into digital signals through an analogue-to-digital converter. The sound waves, thus, are first converted into bits or discrete steps. A digital mixer is essentially a microprocessor that can modify and alter the incoming digital sound signal. Consequently, digital mixers have great versatility and ease of use but do not offer the warm, rich tone of their analogue counterparts.

Powered

A powered mixer is simply a digital mixer with a built-in power amplifier. It has the same advantages as a digital mixer in addition to increased portability.

Digital mixers are very useful for live performances as one can save pre-sets or scenes in the mixer's memory for instant use during a performance. This removes the need to fiddle with individual knobs and sliders as in analogue mixers. Digital mixers have improved radically in quality in the last few years and have replaced most analogue mixers in PA systems today.
Besides digital vs. analogue, buyers must also consider the number of channels and aux ports in the mixer. The channel determines how many different microphones/instruments can be attached to the mixer at the same time. Aux ports, on the other hand, feed need monitoring systems and effects units. Mixers with higher number of aux ports and channels cost more. For an affordable PA system, care must be taken to buy a mixer with only as many channels/aux as needed.
A powered mixer is a good option for an affordable PA system as it eliminates the need to purchase an additional amplifier. Some mixers also have built-in mixers which can further reduce costs.

Affordable PA System Amplifiers

The purpose of an amplifier is to amplify or drive up the voltage of a sound signal and prepare it for delivery to the loudspeakers. The amplifier is connected to the mixer where it performs the job of increasing the power of the outgoing signal as well as managing the resistance or impedance between itself and the speakers. Advanced PA systems may use multiple amplifiers to increase the signal's voltage enough for large venues.
The most important consideration for choosing an amplifier is its power, measured in Watts RMS. For small to medium PA systems, the requisite power of an amplifier can be classified as follows:

Power

Venue/Capacity

200 Watts

50-100 people, appropriate for small studios, lecture halls and large rooms.

600-1000 Watts

100-250 people, appropriate for clubs and small halls.

2000-4000 Watts

250-500 people, appropriate for medium halls and clubs.

As a general rule of the thumb, the power rating of an amplifier should be at least 30 per cent to 50 per cent more than the speakers. Ideally, the amplifier should be twice as powerful as the speakers to allow for enough headroom to meet the requirements of any live performance.
Another important consideration is the resistance, measured in Ohms. The resistance of the amplifier should match the resistance of the speakers. Higher or lower resistance can cause distortion and even damage the speakers. Power amplifiers are available in Ohm ratings of 4, 8, or 16.

Affordable PA System Speakers

The speakers are the final and possibly, the most important part of any PA system. The amplified signal from a power amp is delivered to the speaker where it is converted in acoustic sound waves – i.e. actual sound. Speakers vary vastly in quality, cost and capabilities and it is possible to spend an inordinate amount of money on them. For affordable PA system speakers, the following considerations must be kept in mind:

Types of PA System Speakers

Active

Active loudspeakers have a built-in amplifier. Though not as powerful as speakers with separate amplifiers, these can be a cost effective option in an affordable PA system.

Passive

Passive speakers need external amplification. They offer more power and flexibility, but are also more expensive.

PA System Speaker Frequency Range

All sound is measured in Hertz. Human beings can hear sounds within the 20Hz to 20,000Hz frequency range. A quality speaker must be able to replicate sound within as large a range as possible. In practice, however, speakers can only reproduce sound accurately from a narrow set of frequencies. The better the PA system speaker, the wider the range of frequencies it can replicate accurately.
The frequency range of speakers is measured in Hertz. This unit is usually combined with the speaker's level (measured in decibels – dB) which determines how much certain frequencies have been dampened. Thus, a speaker with a range of 20-20,000Hz plus/minus 5dB means that all bass frequencies have been raised by 5 dB while treble frequencies have been reduced by 5dB. When buying PA system speakers, it is best to select speakers with as large a range and as low a level as possible.

PA System Speaker Volume

The volume of a speaker – also called its sound pressure – is measured in a unit called 'decibel', written as dB. Sounds above 100 dB are perceived as extremely loud and can cause pain and even permanent hearing damage to the listener. Sounds below 20 dB are virtually inaudible to the human ear. Speakers with lower decibel ratings require more power to produce high sound volumes. It is always prudent to purchase speakers with a high decibel rating.

How to Buy Affordable PA Systems on eBay

One can either purchase individual PA system components or buy package deals that include one or more loudspeakers, power amp, mixer, and microphone(s). eBay has a wide selection of both individual components and PA system packages. To buy an affordable PA system on eBay, go to the eBay.co.uk homepage and search for 'PA system' in the Pro Audio Equipment category. The searches can be further filtered by category, such as speakers and monitors, microphones, amplifiers and mixers. PA system speakers can be sorted by brand (Skytec, Ibiza, Auna), by type (active, passive) and by features. PA system microphones can be searched according to type and brand. Amplifiers can be purchased according to brand and RMS power.

Conclusion

An affordable PA system includes a number of separate components. This starts from the microphone which is responsible for converting acoustic sound into electrical signals. This signal travels to the mixer where it can be modified and enhanced before moving to the amplifier which increases its power for playing through the speakers. Advanced PA systems can include dozens of microphones, amplifiers and loudspeakers. Some may even have routers, stage boxes and monitors. PA systems can be purchased either as separate, individual components, or as entire assembled systems. eBay is one of the best marketplaces to buy affordable PA systems with competitive prices and a wide range of products.

Have something to share, create your own guide... Write a guide
Explore more guides