General Buying Guide
Nothing gets your message out more clearly or to more people then with using a PA system. A key component is deciding which PA speaker to use and what to look for when buying PA speakers. Hopefully this short guide will help make the choice easier.
The Power of Powered Speakers
Before active powered PA speakers became available, heavy cumbersome amplifiers had to be lugged around as well as all of the cables and speakers to go with it. Powered PA speakers are much more convenient and light weight. The sound quality is also of a much higher quality. The speaker, as well as its power source and cables are all housed in the same unit, cutting down on size and weight. This also eliminates the need to figure out which speaker goes with which amp.
Mackie's SRM450 active PA speakers are probably the brand and model that put the active speakers on the map. It has a state of the art internal circuitry, which includes a phase-accurate electronic crossover. SRM450's power amplifiers are designed to work seamlessly with each transducer. They are also tightly coupled to the transducers via servo feedback circuitry. The transducers amps are able to 'communicate' with one another. This allows for complete and accurate control and superior sound quality. The state of the art signal processing circuitry allows for control over a whole host of important functions that can't be possible by using a simple passive crossover. The SRM450 is highly recommended.
Bi-amplification is when a single audio signal is divided into two separate frequencies. Each frequency is then sent to separate amplifiers that drive two different speakers. An active crossover network divides the audio into frequencies that are better suited for the drivers that will reproduce them. Bi-amplification also allows the amplifiers to be chosen specifically to match the speakers.
Crossovers are devices that splits audio signals into different frequencies so that they can then be sent to different hubs in an audio system. Though audio is passed through a set of filters. There are two types of crossovers, active or passive. Passive crossovers are usually in the speaker housing along with its components. A single jack is usually the crossovers access to other units. Active crossovers are occur before the power stage and direct the frequencies to its appropriate power amp and transducers. Crossovers can have different filter configurations which result in different results.
To sub woofer or not to sub woofer
The more efficient and cost effective way to add some 'umph' to your PA
system is by adding a sub woofer to the mix. A sub woofer's job is to
produce the deepest bass filled notes. Sub woofers operate at a level
where most regular speakers cannot, and helps those low octave notes
pump out. Besides boosting the quality of low notes without breaking
nearby glass, sub woofers also allow a PA system to run at a low volume
but still retain high quality sound. Sub woofers are available that
integrate themselves seamlessly to most existing speakers, as well as PA
speakers such as the above mentioned Mackie SRM450. Just like with
regular speakers, sub woofers come in the powered and un-powered
variety. A powered sub woofer is ready to use and just needs to be
plugged in. An un-powered sub woofer requires its own powerful
Here is a quick checklist to help you decide when shopping for PA speakers:
Size: Decide what you'll be using the PA system for and this will help you narrow down your choices. Giving a speech to a small room of folks versus a concert to a thousand will require differing equipment.
Number of Sets: What they'll be used for will again be a good indicator here. A single small room could be served by just two column speakers. Whereas a large auditorium would require multiple mounted speakers. Multiple rooms would obviously require multiple sets of speakers as well as multiple power sources.
Powered vs Un-Powered: Powered speakers are going to need extra outlets. Make sure the venue you're using has an accommodating number of outlets, or be prepared to buy some extension cables.
Sub woofer: See the above section to determine if a sub woofer would be of any help. A sub woofer can drastically improve the quality of sound but can also add bulk to an already growing array of equipment.
Placement: Decide where you want your speakers to rest. On the floor? Wall mounted? On stands?