One of the most significant changes in the history of loudspeaker design and development has more to do with amplification than with the speaker drivers themselves. That was the development of the self-powered loudspeaker, which integrated the amplifier package into the loudspeaker enclosure.
The paradigm shift occurred in the mid 1990s when self-powered systems were presented as commercially viable products for live sound use. Covering separate market segments with Meyer Sound's MSL-4 for large-scale systems and the compact and multipurpose JBL EON, self-powered systems had progressed beyond the largely experimental tries at installing an off-the-shelf amplifier into a loudspeaker cabinet. These were purpose-built systems with a dedicated control electronics/amplifier package designed to work specifically with the other components in the system.
The advantages quickly became obvious to the marketplace. "Self-powered systems eliminate variables associated with traditional systems, such as remote amplifiers, processing, amp rack wiring and setup," notes Bob Langlois, Meyer Sound's senior technical support representative. And Jon Sager, senior manager of installed sound for JBL Professional, adds, "The need for an amplifier room is non-existent. This means the church will not need a dedicated room for the amps, eliminating the need for dedicated HVAC to the room, added cost of equipment racks, long speaker cable runs and the larger size of conduit to get signal to the loudspeakers. This reduces the cost of installation and operation."
Other benefits, while not readily apparent, are just as valuable as Gerry Tschetter, vice president of marketing with QSC Audio Products LLC, points out, "When a loudspeaker engineer designs an externally powered loudspeaker, it has to be built to withstand unknown drive power. When an amplifier engineer designs an amp, it has to be protected against unknown loads. But when an engineering team creates a well-designed powered loudspeaker, every element is known. So every element can be cost- and performance-optimized. Signal processing can be fine-tuned to protect the loudspeaker and get the most from the system's acoustical design."
The result is performance that is predictable, consistent, and a system that's easier to set up and harder to blow up. "Self-powered systems can be less prone to user error. For example, a volunteer might see a rack of amplifiers and processing and say, ‘How do I just make this thing go? How do I pass audio through this?' If you're not a pro audio person, a self-contained powered speaker makes it easier to get from A to B more quickly without having to navigate the signal chain in as much detail," says Guy Low of Electro-Voice.
Failure is not an option
On the other hand, though, "The obvious disadvantage is that the amps and processors will be up in the air with the loudspeaker systems. This makes for a more difficult situation should there be a failure," Jerrold Stevens, director of EAW's Application Support Group (ASG), points out. A valid concern-but as Sager notes, "One could argue the same challenges would exist if a transducer were to fail."
The added weight of the electronics package could be a factor, although many systems are utilizing class-D amp technology with switch-mode power supplies, making the weight negligible in many cases. In addition, having an amplifier in each loudspeaker means that you need to supply it with AC, and this can be a costly issue for large-scale systems, particularly if the system is installed as an upgrade in an existing structure.
All shapes, sizes, and applications
Where are we now? Self-powered systems can still be roughly classified into two different categories: one intended for touring or installation (like the original Meyer MSL-4), and one that provides the ultimate flexibility and can be used for a variety of applications (like the JBL EON). There are certainly sub groups for each category, and some manufacturer's product lines may span both categories, so it's recommended that you research their websites for more detailed info.
Line arrays and point sources
The systems listed here are intended primarily for main front-of-house (FOH) application:
Behringer's Eurolive Series (not pictured) includes the B1220DSP, which features an integrated mixer with two mic inputs and can be stacked, configured in a cluster, or stand-mounted.
1 HK Audio's Elements System is designed to be scalable according to application, the HK Audio Elements system features a 10-inch subwoofer, available in a powered and unpowered version, and a mid/high box with four 3.5-inch drivers.
2 K-Array Redline KR200S Powered Loudspeaker
System features an 800-watt, 18-inch subwoofer and an ultra-slim 500-watt line array mid/high box containing closely packed two-inch neodymium drivers.
3 The three-way NTL720 from EAW packs 10 drivers (two LF, two MF and six HF), and three 500-watt, class-D amps in a relatively compact 47-pound package.
4 The Martin Audio MLA system incorporates a class-D, six-channel amplifier module and U-Net, which allows for both digital audio and control to be transmitted to the speakers via Cat5 cable.
5 Meyer Sound's MINA employs a three-channel, class-D amp and can be used in arrays of multiple MINA enclosures or singly as a fill speaker. Rigging options include a grid for flying and a yoke and U bracket for mounting.
The Outline Mini-COMP.A.S.S. iMode (not pictured) is comprised of a two-channel, class-D amplifier and built-in web server for control. Horizontal coverage is adjustable from 60 to 150 degrees.
6 The KLA fixed arcuate line-array system from QSC Audio can be pole-mounted or configured and flown as a complete line array. The ABS enclosure houses a 12-inch LF and 1.75 diaphragm compression driver.
7 Renkus-Heinz's PN/PNX series loudspeakers utilize class-A/B amplifiers, and rigging options include tripod sockets, AeroQuip Fly-track, 1/4-20 attachment points, U-brackets and Omnimount plates.
8 The VXP series from Tannoy incorporates Lab.gruppen class-D amplification combined with Tannoy's Dual Concentric driver technology, resulting in nine
models ranging from a six-inch driver to 15 inches.
The Flex Array TFA-600HDP by Turbosound (not pictured) is a three-way design driven by two independent class-D amp channels (one for LF and one for MF/HF).
9 Yorkville's Paraline Series injection molded ABS cabinet is designed to be stand-mounted via an integrated dual angle adapter, though optional installation hardware is available. Amplifiers draw less than three Amps in typical operation.
Mains ... and monitors Many available systems are designed to be used in multiple ways with the capability to serve as a main speaker or a monitor speaker for installed or portable applications. Fred Poole, product development manager with Peavey Electronics, says, "The portability of powered enclosures make them ideal candidates for use in areas of the church other than the sanctuary. Youth rooms and rec rooms are great places for additional sound reinforcement, and the portability of powered enclosures make them ideal for multipurpose church applications." Examples include:
The Alto Truesonic Series TS112A (not pictured) features two-channel, class-D amplification and two independent mic/line inputs. The polypropylene cabinet includes a pole socket and M-10 threaded inserts for flying.
10 Db Technologies' Flexsys F15 features no less than 12 M-10 points for installation, as well as an angled cabinet for use as a monitor. The rotatable HF horn allows for adjusting the coverage pattern for vertical or horizontal orientation.
11 EV's LiveX ELX115P loudspeakers feature two inputs: one mic and summed RCA stereo input connectors and one selectable between mic and line. The cabinet allows for use as a monitor as well as a main speaker.
12 Galaxy Audio is the manufacturer of the famous Hot Spot monitor, which is so ubiquitous that many refer to a small monitor of any manufacture as a "Hot Spot." You'll find them used in orchestra pits and in front of individual singers and instrumentalists.
Harbinger's HP112 (not pictured) also offers the ability to be used as a floor monitor or mounted on a pole. The bi-amplified speaker uses a class-G low frequency amplifier.
13 As part of the JBL PRX 600 series the PRX635 is a three-way design with a 15-inch LF driver, a 6.5-inch horn loaded midrange, and a neodymium compression driver. The system features a three-channel Crown class-D amplifier. M-10 points for flying are
also included.
14 Incorporating technology designed by the other manufacturers in the Loud family (EAW drivers and a Martin Audio horn), Mackie's HD1221 can be pole mounted, flown or used as a stage monitor.
15 The Peavey Impulse 12D features a ribbon HF driver mounted to a proprietary waveguide that is integral to the molded polypropylene enclosure. The bi-amplified system provides a variety of connections with two inputs.
16 The two-way Samson Auro features a polypropylene cabinet that provides 30- and 45-degree angles for monitor use and is pole-mountable, as well.
17 The Yamaha DSR Series 112 provides class-D amplification with D-Contour multi-band dynamic processing, and can be pole mounted, flown via M10 rigging points, or oriented as a stage monitor.
The crystal ball
Predicting the future-where electronics are concerned-is a slippery slope, and generally technology manufacturers keep planned developments close to their chests, although a few were willing to speculate about what the future holds. The general consensus is that in the near future incremental innovation will yield lighter, more efficient, more powerful amplifier designs. "Over the next 5-10 years, expect powered loudspeakers to deliver more power, weigh and cost less, as well as integrate digital processing that can be controlled via wireless technology into their designs," envisions Sean Meagher, product manager for Samson Technologies.
Which leads us to ... networking. "Powered loudspeakers lend themselves to network control and audio distribution, creating the opportunity for more straightforward and comprehensive control of the installed system," says Jason Baird, research and development director for Martin Audio Ltd. And while many of the systems are set up for networking, remote monitoring and control, the majority of the protocols used are proprietary to the individual manufacturers. Some have joined the AVnu Alliance in promoting Audio Video Bridging (AVB) as the new standard. Meyer Sound's director of technical support worldwide, John Monitto states, "The emerging set of AVB audio video bridging network standards from IEEE provides an invaluable opportunity for the reliable delivery of high-quality audio and video streams. Users of self-powered systems enabled with AVB can benefit from networked audio, control, and monitoring."
All this technology aside, the ultimate goal is to produce products that perform better, are easier to install and operate, and last over time. EV's Low adds, "Any emerging technologies that are cost-effective and make sense will be integrated into making these systems more user-friendly rather than more complex. With each new generation of products, we strive to provide a combination of the latest high-performance technology with increased ease-of-use, and powered loudspeakers are a place where you'll really see that borne out."
Langlois suggests, "To optimize the performance of any audio system, it is important to remove variables from the installation process. Using self-powered loudspeakers enables a simple integration process, and this allows churches to focus on engaging the congregants."
