Compact line arrays—imaging, power, affordability make them hot tickets.
Over the past decade, large-format line arrays have built a loyal following in the live event world. More recently, compact versions have been growing in popularity, especially with engineers desiring the uniformity of distribution, enhanced stereo imaging, and responsiveness, but with a smaller footprint. Today, most major concert loudspeaker manufacturers have introduced lighter, less expensive systems that are easier to bend in an arc that is more suitable for covering smaller spaces. This issue, I'll review a bit of line array history and look at products comprising the market.
Old Concept, New Day
Conceptually, line arrays have been around for many years. According to material published by Electro-Voice, writings on the notion of vertical orientation of sound sources date back to 1896. In the 1950s and 1960s, columnar speaker systems were popular for providing vocal intelligibility in reverberant spaces.
Prior to manufacturers developing horn-loaded, modular systems for PA in the late 1960s, several bands experimented with this approach. While the highly directional, long-throw properties of line arrays were pleasing, cancellation problems in the near field made them less attractive to manufacturers. People continued flirting with the concept over the years, as illustrated by the Grateful Dead's “Wall of Sound,” but the approach didn't capture the imagination of the technical community until 1992 with the introduction of Dr. Christian Heil's line array design, called V-DOSC, for France's L-Acoustics.
Many live sound engineers point to V-DOSC as the turning point that inspired many companies to investigate and invest in developing line array systems. In particular, V-DOSC's properties provided a lot of gain before feedback, good overall coverage in large venues, excellent imaging for audiences, and increased control over the mix for the front of house engineer. Beyond performance pluses, the speakers were also easier to pack in a truck than other non-line array systems. As V-DOSC gained rave reviews from engineers and audience members alike, it didn't take long for major U.S. companies to take note.
Roughly translated, V-DOSC means Cylindrical Sound Wave Generator, with the “V” referring to the Heil's proprietary acoustic lens configuration for mid- and high-frequency sections. It was Dr. Heil's development of VOSC's wave-guide technology that provided a means to couple high frequencies from one speaker in an array to the next, ensuring a flat, isophasic wavefront.
As other manufacturers began to develop their own systems, some pursued waveguide approaches to coherent high-frequency coupling, while others took to using multiple-horn elements to better control that range. Developing approaches to coupling was particularly important. The introduction of arcs in arrays for better coverage meant an increased angle between adjacent speakers, and also revealed problems in the behavior of frequencies. (Past 5 degrees, the high frequencies no longer couple, and coverage is compromised.) Over time, some engineers chose to use split-process clusters, dividing them into long-throw and near-field specific categories. While modifying factory-set crossover points was particularly discouraged by Dr. Heil, some engineers saw deviating from strict settings as a necessary approach to achieve the best sound in a specific venue.
It didn't take long for folks like EAW, Electro-Voice, JBL, and Meyer Sound to introduce their own systems in the mid- to late-1990s. With several major companies providing systems as I write this, the appeal of line arrays is by now no faddish marketing trend, but rather, it's an established approach that is finding expression in smaller venues.
Large and Small
It didn't take long for designers to conceive of smaller footprint line arrays that would suit a broader variety of venues. Compact systems are easier to bend, easier to hang, and can provide unbeatable coverage in most venues. However, they are typically not designed to be full-range systems, and need to be supplemented with subwoofers for adequate bass response.
Below, I've included a list of line array systems available today. While some may not be typically viewed as compact, they are finding a place in smaller venues and therefore merit inclusion. This is not intended to be an exhaustive list of what is considered “compact,” rather, it's a representative sample for your perusal. Check each company's website for detailed info.
Adamson: Introduced last year, SpekTrix is an ultra-compact three-way cabinet featuring dual 8.5in. Kevlar Neodymium drivers and one B&C DE 900 compression driver mounted on their patented wave shaping sound chamber. (www.adamsonproaudio.com)
Apogee Sound International, LLC: The first modular line array introduced, ALA-3 features dual 10in. cone type drivers with two 1in. throat compression drivers between them. (www.apogee-sound.com)
EAW: The KF730 SLAM (Small Line Array Module) is a three-way bi-amped speaker featuring dual 7in. drivers and dual 1in. compression drivers. At either end are 10in. woofers. The SB730 is its companion subwoofer. (www.eaw.com)
Electro-Voice: The Xlc127+ is a tri-amped, three-way enclosure using two of the same compression drivers as the X-Line. It features an asymmetrical design with a single 12in. at one end, two horn-loaded 6.5s on the other, with two Neodymium drivers down the center. Xlc124 provides downfill, with the Xlc118 as a companion 18in. subwoofer. (www.electrovoice.com)
JBL: The VT4887 is a dual 8in. bi-amped three-way design, while the VT4888 features a dual 12in. design, with the VT4881 provided as a companion dual-coil 15in. sub, which can be coupled to all VerTec arrays in hanging or ground-based applications. (www.jblpro.com)
L-Acoustics: dv-DOSC is an active two-way system with two 8in. and one 1.4in. compression driver. Its companion dv-Sub offers a vented, bandpass triple 15in. design. (www.l-acoustics-us.com)
Martin Audio: Provides the only horn-loaded three-way, the W8LC, and is tri-amped like the large-format W8L. It can be complemented by either the W8LS Line Array subs or WSX horn-loaded subs. (www.martin-audio.com)
McCauley Sound: M.Line is a two-way speaker in three versions with different HF horns. Designers can choose between vertical coverage angles of 60 degrees, 90 degrees, or 120 degrees. Sub frequencies are addressed by their CSM88 coupling subwoofer modules. (www.linearray.com)
Meyer Sound: M1D is a self-powered, bi-amped enclosure employing dual-5s and triple dome tweeters. Companion subwoofer is the dual-10 M1D Sub. The M2D is a self-powered, dual-10 enclosure with a companion self-powered dual-15 M2D Sub that integrates into arrays. MILO features a single 1.5in. compression driver, and above 4kHz, three 0.75in. compression drivers are provided for long throws. Introduced as this issue goes to press is the MILO 120, optimized for the shorter throws and lower SPL of downfill applications. It's designed to be a downfill complement to standard MILO or M3D line array cabinets. (www.meyersound.com)
Nexo: Geo-S805 employs a single 8in. woofer passively crossed over to a 1in. driver mounted on its patented Hyperboloid Reflective Wavesource. The S830 is a companion downfill module with 30 degrees of vertical coverage. Its companion subwoofer is the CD-12. (www.nexo-sa.com)
Renkus-Heinz: The PNX 102/LA is a two-way enclosure with dual-10s and dual 1in. exit compression drivers that features 150 degrees dispersion with no horn-loading. It can also be ordered as the self-powered PN 102/LA enclosure, which has an R-Control supervision network and weighs an additional 10lbs. (www.renkus-heinz.com)
SLS: The LS6500 is a lightweight, compact line array module featuring a 100W RMS, 6.5in. woofer, and an SLS PRD500 5in. Planar Ribbon Driver in a compact bass reflex trapezoid enclosure. With horizontal coverage of 110 degrees, multiple LS6500 modules form the newest addition to the SLS Line Array Series, the RLA/3. (www.slsloudspeakers.com)
Alex Artaud is a musician living in Oakland, Calif. He thanks Mark Frink for his help with this article.