Powered Pro Audio Speakers

Powered PA speakers comes down to convenience and sound quality. If you're not familiar with active PA speakers, the idea is that the power and all connections are simply built into the same cabinet as the speaker. This all-in-one design also takes the heat off of those of us who don't really know how to marry the right power amp with the right speaker, which can lead to degraded sound quality at best and damaged gear at worst.

The Mackie's SRM450 active PA speaker takes the whole self-powered concept to the next level with sophisticated internal circuitry, including a phase-accurate electronic crossover. Their power amplifiers are :

1) optimized to work perfectly with each transducer and,

2) tightly coupled to the transducers via servo feedback circuitry. In other words, the transducers can "talk back" to the amps. This closed system means total, precise control and far better sound. Plus, having sophisticated signal processing circuitry on board lets you exercise control over a wide range of critical functions that you cannot get from a passive crossover system. The SRM450 sounds great!

Today, there are several lines of active PA speakers to choose from, all with different features and benefits. For instance, Yamaha's MSR250 is quite a bit smaller than the SRM450, so they can be used in smaller rooms as PA speakers or in bigger setups as powered monitors. Plus, the MSR100 has a simple but effective mixer built into the rear of each unit that provides three inputs with master EQ for precise sound control.

When Do I Need to Use a Subwoofer?

Looking to add some low-end thump to your PA system without having to upgrade all the existing gear you're using? Then you want a subwoofer ("sub" for short) - a speaker that's dedicated to producing the lowest of the low notes.

Generally subwoofers handle reproducing audio signals in the 20-100Hz range - sometimes a bit higher and occasionally a bit lower. Basically (no pun intended) a sub is used to pump out the lowest octave or two, below where many "full-range" speakers can effectively operate. It takes a great deal of amplifier power and a large speaker to produce those low tones at room-filling volumes. If a sub were incorporated into a full-range speaker, the cabinet would likely get unwieldy.

So when do you need a subwoofer? When the kick drum goes "tick" instead of "thump," when the low notes on your bass guitar, piano, synth, or electric tuba are sounding decidedly anemic, when your beats aren't inciting dance-frenzy in the masses - in any of those cases you may be a candidate for some low-end reinforcement. But there's another reason to use a sub. Having a sub's big low-end response often means that you can run your PA at a lower volume level while still retaining a fat, full sound.

You can buy subs that "match" with most popular full-range speakers; they have their frequency response and crossover specifically tailored to provide a smooth transition between what the sub is doing and what the full-range speaker is doing.

As with full-range speakers, you can get powered and un-powered subwoofers. Powered models are very convenient - just plug in and go. Un-powered models will require a separate power amplifier (with LOTS of power) and possibly an external crossover.

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