Making a decision on the type of system to purchase is a very difficult task. Any wrong choice can make or break a company, especially in today's economy. That's why it is important to understand the advantages and disadvantages of different technologies and make the best choice for whatever the situation may be.
I remember reading FOH magazine about seven or eight years ago and seeing a huge boom in powered loudspeaker products. When that happened, it brought up some interesting questions, such as, "Will self-powered loudspeakers completely eliminate the use of conventionally-powered loudspeakers?"
At this point in time I think it's safe to say that both have been able to stand the test of time. While self-powered loudspeakers have benefits in some situations, conventionally-powered loudspeakers outweigh those benefits in other situations. It all depends on what you're looking for.
Power It Up
While the big boom of self-powered pro audio loudspeakers has happened within the last decade, the first loudspeakers of this type were actually developed more than three decades ago, and developments in self-powered loudspeaker technology continue.
At first, the big selling point of these self-powered systems was the difference in the damping factor when compared to conventional amplification. The damping factor is listed in any given amplifiers' specifications. In a nutshell, the value of the damping factor is a representation of how well the amplifier can control the speaker from unwanted vibrations. This is most relevant to low frequency reproduction (low-mid, woofer and subwoofer applications), like a kick drum hit, for example.
An amplifier with a good damping factor will not only help push the speaker out, but help it pull back in quickly, which makes for a nice, tight kick sound. On the flip side of that, an amplifier with a poor damping factor will push the speaker out but not pull it back as quickly, which can lead to a more "muddy" sound that is not as punchy.
One of the things that can affect the damping factor is the length of the cable that gets used. Basically, the shorter the speaker cable length is, the better the damping factor will be. This is the big selling point of self-powered loudspeakers. Because the amplifier is right inside the box, a self-powered loudspeaker has a cable length of no more than a couple of feet, versus a couple hundred feet for conventionally-powered loudspeakers.
Brains Onboard
Most of today's self-powered loudspeakers include full processing with networking capability. This is extremely useful, and some manufacturers have found new ways to take full advantage of this. When a line array is flown, as more boxes are added, the low end will increase and the high end will decrease.
Meyer Sound, for example, has a processor that can be used with their self-powered line array. The processor compensates EQ and level between boxes for any given speaker array size to maintain the sonic characteristics that the manufacturer intended. Martin Audio has recently taken this a step further with separate processing for every component within their new line array, allowing for an even more in-depth array compensation. To do this on a conventionally-powered system would require many extra processors and amps compared to what is normally used.
On smaller gigs, self-powered loudspeakers have even more advantages. They take up less space in the truck because there's no amp rack to lug around. Some boxes are equipped with a mic/line switch, which allows the user to plug a microphone right into the speaker. Some even have an EQ adjustment built right onto the box, which can help or hurt you, depending on your situation.
All in all, there are many benefits to self-powered loudspeakers. They are pre-processed from the manufacturer, take up less truck space and can be more versatile in some situations.
Conventional
While self-powered loudspeakers are very popular, sometimes it's best to just go with the "old school" way of things. Some repair techs I've talked to put it in really easy terms: If a self powered box amp module fails (assuming the system is flown), you have to get a lift and replace the module or potentially even bring the whole rig down. If a conventional amp fails, you just move the speaker cable over to another amp rack. That is one of the reasons many tours still travel around with conventionally-powered rigs.
Another advantage of conventionally-powered loudspeakers is weight. Any box without an amplifier inside of it will be anywhere from 10 to 40 pounds lighter. That may not seem like a lot, but at the end of a long day, it can sure feel like it. This is also a big difference in the weight of a flown array. A conventional box will almost always be lighter than a self-powered array.
The initial cost of a conventional system may be less than a self-powered system. A self-powered system has the cost of an amplifier in every box. With conventional amps and boxes, one amplifier is usually linked to power multiple enclosures. Also in a conventional system, one amp rack can usually power different types of enclosures. This might mean that fewer amplifiers have to be purchased.
Two Systems, One Goal
Both self-powered and conventionally-powered systems have their benefits. But the bottom line is that both can get the job done. It can be argued for eternity which type of system is better, but at the end of the day, both systems have the same goal: to make the show sound good. There are many options out on the market, with more popping up all the time. With the right design for the right situation, a very versatile system can be created.
