Your Guide to Buying Wireless PA Speakers

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Your Guide to Buying Wireless PA Speakers


Public address (PA) systems have been in use for decades to amplify voice and music, allowing the address of large audiences with little effort. The first patent for a loudspeaker was filed by Edwin Jensen and Peter Pridham in 1911, and since then PA systems have become a critical part of any application where voice amplification is required.

Benefits of Wireless PA Speakers


The benefits of wireless PA speakers in are numerous and diverse. In the past, a PA system would have required the linkage of a multitude of devices with cables strung throughout the venue, creating an untidy workspace, as well as a plethora of potential hazards. A set of wireless PA speakers allows the addition of any number of speakers to a network all without wires, therefore, allowing even those speakers found in isolated locations to be linked with ease. Wireless PA speakers also create the opportunity to add a wireless microphone to the system, allowing performers or speakers to enjoy the freedom and professional appeal associated with this calibre of equipment. Wireless PA systems also allow a quick and easy way to connect multiple devices together without having to invest in cumbersome cable splitters and hubs, and since wireless systems often transmit their signals through digital channels, the possibility of interference interrupting the transmitted sound is vastly reduced when compared to that of expensive shielded cables.

Choosing the Ideal Wireless PA Speakers


Since wireless PA speakers come with so many varieties and options available, it is important to do the appropriate level of research before committing to a purchase. Three aspects of a PA system are important enough to be considered in great depth: the pickup, the amplifier, and the loudspeaker. Purchasing a low-quality version of any of these components will result in an overall reduction in the efficiency of a system. Many wireless PA systems available today are fabricated by the manufacturer, who compiles a selection of components of similar quality into one unit for sale. While this is likely the quickest and easiest way for most people to obtain a low cost PA, serious users may wish to experiment with putting together their own for best results. This section deals with the best options to choose from in order to get the highest-quality wireless PA system for the lowest price.

Choosing a Microphone


The microphone is the point in the system which receives the sound input and transmits it into electrical signals ready for transmission or amplification. Two types of microphone are commonly used in wireless and PA systems: dynamic microphones and condenser microphones. The advantages and disadvantages of each of these are summarised in the table below.

Dynamic microphone
 

Dynamic microphones work by converting the movement of coils induced by sound waves into electrical signals.
 

These microphones are cheap and compact, allowing for easy use on stage or in a recording studio in the home.
 

Because of the limitations of their design, dynamic microphones result in inferior sound quality when compared to condenser microphones.

 

Condenser Microphone
 

Condenser microphones contain a thin membrane suspended between two charged plates, forming what is essentially a capacitor. As sound waves penetrate the microphone, vibrations in the plates and membrane change the capacitance of the device, allowing sound waves to be detected and amplified.
 

Condenser microphones are much more sensitive than dynamic microphones, making them especially useful in recording studios, although more and more artists are beginning to use them on-stage.
 

The sensitivity of condenser microphones makes them incredibly fragile and therefore unsuited to the harsh use associated with tour and on-stage performance. These microphones are also understandably much more expensive than dynamic microphones.

 

Battery or Mains?


The power requirements of a wireless PA system vary with its application. Generally, the higher the power of a PA system (measured in Watts), the greater amplification it will produce. For addressing a small function room, a battery operated wireless PA system will likely be sufficient. For addressing a large concert hall, though, a mains powered system will likely be indispensable. It is also important to keep in mind that the roof and walls of an indoor venue reflect sound, having the effect of increasing the perception of amplification of the sound. Outdoor venues have no such reflective surfaces, and sound is simply able to escape into the surrounding environment. Any outdoor events will, therefore, require a wireless PA system with a greater than average power in order to provide the necessary amplification. A general guide to the power required for various scenarios is shown in the table below:

Speech
 

80-100 square metres/50-100 people
 

100 Watt

 

Small musical event
 

200-400 square metres/100-250 people
 

300-500 Watt

 

Large musical event
 

800-1000 square metres/250-500 people
 

1000-2000 Watt

 


A good strategy to employ when estimating a PA system's power requirements is to always purchase a system with an overall power rating in slight excess to these predictions, and an amplifier which can supply a power output slightly greater than what the speakers can transmit; a PA system working comfortably within its range will produce a much cleaner output than one which is barely able to cope with the required amplification. In addition to concerns about the acoustic environment of a PA system, the type of input can also profoundly affect a system's power requirements. Music playback can almost double the power needs of a wireless PA system due to the increased spectrum of frequency dealt with.

Choosing a Loudspeaker


The loudspeaker is the heart of any PA system, so being well informed about the specifications to look out for when choosing a loudspeaker is of great importance. The essential specifications required are shown in the table below:


Cabinet Design
 

The design of the cabinet into which a speaker is placed can have a dramatic effect on the depth of sound produced by the system. Simply experimenting with materials of different densities and cases of different shapes and sizes is usually the best way to find the ideal wireless PA speaker.

 

Frequency Range
 

The human ear can detect sounds between 20Hz and 20000Hz, and so it is natural to assume that a good-quality speaker will be able to provide sound output over this whole range. Only very few speakers can deal with this entire range, though, meaning that choosing the right speaker is important. Most loudspeakers will be able to transmit optimally at high, medium, or low frequency ranges, but not all of these. The key aspect when choosing a frequency range for a set of speakers, however, is a property known as linear transmission. Linear transmission describes the ability of speakers to transmit consistently and efficiently within the optimal frequency range of the device.

 

Impedance
 

Speaker impedance values are particularly important when selecting a speaker which will be compatible with an amplifier. Impedance values describe the resistance of a device when under the influence of AC current, and are given as a value in Ohms, the units of resistance. Typical speakers have impedance values of 4 or 8 Ohms. Speakers with impedance values which are not matched to the amplifier they are connected to can damage the system, so this specification warrants care and attention when choosing devices.

 

Power
 

Making sure that the amplifier can transmit around 30 per cent more power than the speakers connected to it ensures that the amplifier has more than enough power to supply the speaker, even during spikes in the audio input, without compromising on quality.

 

Buying Wireless PA Speakers on eBay


A search for 'wireless PA speakers' directly from the eBay homepage yields just a few hundred results, but even this is too broad for most users. Honing of the results is possible through the use of eBay's powerful category system. Firstly, click on Musical Instruments under the Other categories section in the Shop by category menu at the top of the home page. Under Pro Audio Equipment, select Speakers and Monitors. The left hand side of the page now lists several check-boxes which can be selected. Check the PA Speaker box to narrow results even further. Selection by brand and other features is also possible here, but simply typing 'wireless' into the search bar now generates a much more refined list of results to begin searching through.

Conclusion


To find the best deals on wireless PA speakers, second hand retailers such as eBay can provide a vast range of results. Keeping in mind the specifications detailed above is a sure way to get just the right wireless PA speakers, and will allow intelligent decisions to be made about the unit required.

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