The precursor to powered speakers came into existence when a few sound companies started suspending their amp racks right behind the hanging loudspeakers to shorten cable lengths. The first “true” powered speakers came about in the early 1980s, when one rental house installed rack-mounted amplifiers into large, horn-loaded loudspeakers. Around the same time Altec-Lansing offered a small two-way speaker with built-in amplifiers. It turned out to be more of an experiment than a game changer. About 20 years later, a few daring manufacturers came to see the benefits of placing amplifiers mere inches away from a loudspeaker's drivers.
Powered? Or Not?
Let's take a look at why you may—or may not—wish to select a self-powered loudspeaker system for your worship center, or for portable use in your church environment. There are several disadvantages to powered systems that are important to be aware of:
THE CONS
1. Repair.
Depending on where the speaker is located, field repair may or may not be an issue. You probably don't want power amplifiers built into speakers intended for use in an outdoor playing field that will encounter inclement weather. The cost of replacing a failed amplifier in a powered loudspeaker could be significant if accessibility is limited. That said, drivers fail at least as often as most modern amplifiers fail. Amplifiers can be designed to shut down via a variety of protection schemes. Drivers are not so lucky.
2. AC Power.
Powered speakers need AC power. This might require hiring an electrical contractor, depending on the size and type of the system and local regulations. Electrical work can quickly become expensive when union labor is involved. Conversely (and this especially applies to new construction), the electrical work may be funded by a different budget than the audio work, resulting in a form of phantom cost savings. At the end of the day, AC power must be installed and paid for somehow, but if it reduces the audio budget by a meaningful amount, it may free up funds for other purchases.
3. Overheating.
Powered loudspeakers remain “in fashion” because the leading brands of self-powered products usually represent the best that a given manufacturer can provide.
Overheating is a real issue when a powered loudspeaker is used outdoors in hot weather or under improperly focused high-power stage lighting, or when direct sunlight is hitting the rear of the enclosure where the internal amplifier's heat sink is usually located.
4. User Control.
With some brands of powered speakers, the internal crossover (typically DSP these days) cannot be altered. This inability to make user-based alterations to crossover points and slopes can be seen as a problem. Many engineers, system designers, and installation contractors want to generate their own crossover and EQ settings; this is part of the service they provide.
THE PROS
1. Power Matching.
Internal amplifiers are designed to deliver optimal power to the drivers. But even more important is the protection scheme—usually involving factory-designed, signal-level limiters. Properly engineered, a good factory protection scheme should keep blown drivers to a minimum without unduly harming sonic quality. But proper design is the key: it's quite impossible to set outboard limiters by ear to achieve driver protection without compromising dynamic range. Protective limiting requires extensive destructive testing of a representative batch of drivers, which is exactly what a serious manufacturer will do during product development. There is no other foolproof way to determine optimal limiter thresholds and rates.
2. Damping Factor and Line Loss
All drivers have mass. When the drive signal ceases and the amplifier stops being an amplifier, it becomes an electrical brake. The longer the cable between the amp and the drivers, the less the braking action. Very short cable lengths permit the amplifier to more effectively dampen the drivers' mechanical momentum. This results in a tighter, crisper, more accurate sonic quality, with measurably better transient response. Line loss in the cable run is also reduced, usually significantly, which means that smaller amplifiers and lighter electrical loads are able to get the job done. In situations where available AC building power is already maxed out, and many loudspeakers are required to fill a large sanctuary, this can be a decisive factor.
Amplifiers can be designed to shut down via a variety of protection schemes. Drivers are not so lucky.
3. frequency and phase response.
By employing a DSP front end, or sophisticated analog circuitry, a powered speaker can be factory-calibrated to exhibit highly uniform response curves in critical performance parameters. This is a seriously elusive goal if the end user is free to adjust crossover settings on a rack-mount loudspeaker management product without a deep understanding of how each change interacts with another. Calibrating an individual loudspeaker, or an entire system, is not just about what you hear during a quick setup session. In fact, it's far easier and faster to tune a well-designed system to compensate for room acoustics, than it is to optimize an individual loudspeaker during the initial product design and development phase.
4. Space Savings.
Powered speakers take up less space.
5. Remote Control and Monitoring
Many of today's high-end powered speakers offer a means of connecting a wireless tablet to the loudspeaker's control network and making adjustments from anywhere within WiFi range. This benefit does not apply as much to permanent installations, but more to traveling/touring systems where quick fixes need to be made on a daily basis.
CONCLUSION
Powered loudspeakers can provide numerous benefits—as well as the potential downsides we discussed above. It's a good bet that a powered speaker solution can fulfill the needs of your ministry by providing top-notch sonic quality to keep the congregation with impeccable clarity, while eliminating many traditional setup and operational problems. Powered loudspeakers remain “in fashion” because the leading brands of self-powered products usually represent the best that a given manufacturer can provide. Cost savings of using powered speakers, such as eliminating speaker cable runs and avoiding the need for an amplifier room might initially appear to be the better choice, but the choice should always be dependent on specific application requirements.
