Speakers: Why Powered Speakers?

by Mackie Designs

Why Powered Speakers?

As you probably know, all speaker systems require an amplifier. Better speakers systems may require two or three, one for the low frequency driver and one for the high frequency driver (this is called bi-amplification). Speakers that require a separate power amplifier are called "passive", meaning that the speaker is capable of nothing until you hook an amp up to it. A new breed of speaker system has been growing in popularity. They are referred to as "active" speaker systems and they have the amplification and signal processing built right in it. The advantages to this approach to you, the customer, are tremendous. Let's take a closer look.

Active Advantage #1: Value

Active speaker systems provide tremendous value. By including an amplifier, speaker and signal processing (EQ & crossover) in the same box, there is a huge cost savings through the ability to share the chassis and power supply. Additionally, because we know what speaker an amp is required to drive, the engineers don't need to overbuild the power amp the way we would traditional stand-alone amplifiers. These cost savings allow us to use better components and still offer the systems a very attractive pricing.

Active Advantage #2: Improved Damping

A speaker converts power into motion: the speaker receives an electrical impulse and it moves to convert it into an acoustical impulse. Unfortunately, as the speaker tries to recover to a resting position, the momentum of the motion can actually generate electrical impulses back down the speaker wire to the amplifier (called electromagnetic force or "back EMF"). The amplifier's ability to "dampen" or brake the speaker's motion is critical to the sonic integrity of the speaker/amp system. Active speaker systems have a tremendous advantage over passive systems when it comes to damping, because the amplifier in the speaker can be finely tuned to maximize the damping characteristic of the individual speaker it is controlling. The results of effective damping are tightly controlled, and very accurate bass response.

Active Advantage #3: Better Sound

Power amplifiers vary widely in output ratings, damping factors and sound characteristics. Active speaker systems eliminate the guesswork of trying to match the best amplifier for a specific speaker, tailoring the amps to the optimum power requirements of the specific speakers they will be driving. Active speaker designs are typically bi or tri-amped, having two or three amplifiers, each one dedicated to a specific task (low's, mid's or high's), and provide opportunities for more precise crossovers, active equalization and time correction in the speaker system. The result is a much more controlled, uncolored sound - and usually for less money than a separate speaker/amp combination.

Active Advantage #4: Better Protection

In passive system, you have to rely on some sort of crude circuit or fuse (or the user!) to provide protection to the speaker components. Having control of the entire amplifier/speaker signal chain allows design engineers to precisely control the maximum power going to the speakers. Each amp can be directed to a limited to a specific frequency spectrum. Output power, running temperature and headroom are all consistent in the design phase of the product so it can be optimized for the highest output and performance. The result is improved reliability and far fewer speaker failures.