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How To Choose The Portable PA System That's Right For You - Part One.

First of all, it is worth noting that this article does not deal with PA systems designed for DJ's or live bands! Instead, we concentrate on systems which are used primarily for voice or music reinforcement, i.e. for localised communication and smaller scale entertainment.

Fundamentally, taking the above qualification into account, there are two types of portable PA (public address) system which are differentiated by their derived source of operating power. The options are for a wireless re-chargeable battery powered system or the more traditional wired mains electric powered system.

An Introduction to Battery Powered Portable Public Address Systems

Also able to run on mains power when appropriate, battery powered portable PA systems are far more flexible in their range of applications and locations as they are not dependant on a mains supply being close at hand and so are very popular for outdoor use. Typical examples would be for sports events, fetes, carnivals, busking, market stalls, auctions, guided tours, etc. However, their indoor use is also very valid for presentations, conferences, meetings, etc. as they are quick and easy to set up and eliminate the existence of trailing cables.

The down side of battery powered portable PA systems is the limitations placed on them by the internal battery itself which restricts the continuous operating time to anything between 5 and 8 hours as well as limiting the audio output power to a maximum of 250W. Nonetheless, such maximums are very often more than adequate for users of this type of equipment as their events are rarely any longer and their audiences never excessively large. Conversely, multiple units can, of course, achieve much higher output levels and greater coverage but at an increased cost. The concept of multiple wireless PA speakers will be addressed in a later section of this article.

Battery powered PA systems are mostly all-in-one solutions. They house the speaker(s) at the front, the batteries, amplifier and circuitry inside and the control panel on the back. The majority of models feature wireless 'radio' microphones to maintain the wireless operating principle of the system as a whole. Working in conjunction with the microphone receiver(s) built into the PA unit, the microphones themselves can be of the hand held, lapel or headset variety. An additional cabled microphone input is often featured too.

Additionally, for sheer convenience, many units feature integral CD players, cassette decks and even DVD players as well as MP3 recorders or players plus USB input connectivity and external memory SD card slots.

Battery powered PA systems provide the most flexible solution for indoor and outdoor events where their wireless features are definitely necessary or simply convenient.

LOUDSPEAKERS – Active or Passive? – Part One

Within the realms of professional audio, much is often said regarding the pros and cons of a PA system featuring active or a passive speakers. Avoiding the ‘techno speak’, here are the facts. For ease, we will refer to a loudspeaker box or loudspeaker enclosure containing one or more drivers as a speaker.

A passive speaker is the more traditional way of doing things. It has no internal amplifier and is connected to a power amplifier, located at a convenient and perhaps remote point within the venue, via traditional speaker cable. The speaker itself might contain a single driver e.g. a sub-woofer where the original audio signal has previously been split up into frequency bands so that the correct range of frequencies go to the correct driver(s). Alternatively the speaker might actually comprise of two or three drivers e.g. bass, mid, high featuring a passive crossover within the box which takes the entire audio signal and splits them up (as best it can) to each appropriate driver.

An active speaker is where the power amplifier for each driver is actually located inside the box as an all-in-one solution.

In professional sound systems there will be two or three integral dedicated power amplifiers – one for each size or type of driver. In this instance, there will also be an active (or electronic) crossover that acts in the same way as an external active crossover in a passive system, accurately routing the right frequencies to the right driver. Active speakers are connected to the mixing desk or audio source via screened signal cables.

A self powered portable PA system such as those from SoundPlus, dB Technologies and Mipro which have integral

re-chargeable batteries can, to a degree, be referred to as an active speaker as they obviously have their own amplifier on board although some may say that, as they don’t have dedicated amplifiers for each driver and rely on a passive crossover, they are not strictly active PA speakers and are merely self-powered!

In Part Two, we will look at the advantages and disadvantages of active speakers vs. passive speakers.