Since its introduction less than two years ago, Martin Audio’s revolutionary Multi-cellular Loudspeaker Array (MLA) has won accolades and nearly every industry award. Horn loading has always been Martin’s hallmark and recent heritage also includes the large-format Longbow and medium-sized W8LC line arrays.
MLA Compact brings Martin’s revolutionary cellular technology behind MLA to a wider range of touring and installed sound reinforcement, with a smaller enclosure that gets almost as loud as MLA. Anyone who has worked with MLA understands that it often uses less than half its headroom in typical applications, even outdoors.
Like its older, larger sibling, the self-powered MLA Compact retains individual control of three-way drive sections within each cabinet, leveraging DISPLAY2.1 software to create custom settings for each enclosure that optimize overall system performance for a specific venue. It improves upon the limitations of typical zoned approaches to line array optimization and avoids the use of presets, instead relying on a powerful predictive program’s accurate modeling of the system in its intended venue and listening area.
Inside the Box
MLA Compact’s low-frequency section employs dual 10-inch neodymium woofers that are Hybrid slot-horn loaded into short horns with a low flare rate emerging at each end of the baffle’s front, improving sensitivity to 103dB, while the woofer’s reflex-loaded rear extends output to 65Hz. MLA Compact’s Hybrid LF arrangement combines best practices: efficiency and punch that direct radiators can’t match with vented LF extension.
Slot-loading allows the twin LF drivers to be optimally spaced within the enclosure and the double-source arrangement improves directivity, maintaining 100° system beam-width down to 250Hz and reducing mid-bass at the sides and rear. The 500W AES LF drivers themselves are very high excursion with vented poles to reduce power compression and eliminate turbulent noise.
Crossed over at 400 Hz with 48 dB per octave LR filters, the mid-range section employs two horn-loaded five-inch neo cone drivers. Beside them is a column of four 0.7-inch exit neo compression drivers on individual horns, ensuring 100° horizontal constant directivity. A smaller version of MLA’s “toroidal phase bung” extends MF performance above 4kHz, while the HF horns have patented diamond-shape cross-section wedges in their throats to accurately determine curvature of the HF waveform.
Because the HF and MF sections are “side-by-each,” their transition band is minimized to a fraction of an octave using “Vanishing Point” 4250Hz FIR crossovers that minimize interference between the adjacent MF and HF horns, allowing them to perform like a single device.
The 109-pound enclosures are 11 inches high, 31 inches wide and 20 inches deep. Up to 24 can be suspended via a two-point-lift flybar that allows single point lifting of up to 12 cabinets, as well as ground stacking up to 6 high. The vertical cabinets have 5° wall angles and provide up to 10° of vertical splay.
MLA Compact’s horizontal coverage is referenced at 100° (-3 dB) and 130° (-10 dB), 10° wider than MLA. All three bands of MLA Compact are rated 129dB continuous, 135dB peak, which is only 4 and 5 dB less than the 193-pound MLA in the lows and mids.
Each MLA Compact is self-powered with a Class D five-channel amplifier delivering a 2kW/4kW continuous/peak total output. One channel powers both LF drivers, two channels drive the individual mid-range horns and two channels drive the four HF drivers in pairs.
Lightweight, switched-mode PSUs auto-range to international voltages from 100 to 240V and Power Factor Correction reduces AC mains current. Efficiency of MLA Compact is about 78%, while efficiency of its companion DSX subwoofer is about 85%. The amp module is designed to withstand rain and ambient temperatures to 113° F.
The 269-pound dual-eighteen DSX subwoofer also comes in a flying version. The ground-stack DSX is upgraded to the DSX–F by the addition of an easy-to-fit accessory kit that adds 56 pounds per cabinet, ex wheel-boards. The DSX-F upgrade adds four proprietary flying brackets with quick-release pins, rear castors are replaced by front-mounted wheel-boards and four interlocking rubber side cheeks replace side-mounted skids.
The DSX-F subwoofer can be flown alongside or, using a transition frame, at the top of MLA Compact arrays. A maximum of 15 DSX-F can be suspended from the MLA flying frame and symmetrical rigging allows individual flown DSX-F cabinets to face backwards — enabling directional flown arrays to be configured as well as ground stacked.
DISPLAY Software
MLA Compact is a fully integrated system, combining state-of-the-art loudspeaker design, amplification and DSP with unique, predictive optimization software operating on a PC or wireless tablet running VU-NET control software. Onboard Class D amps with DSP simplify set-up and operation, eliminating speaker cables and amp racks, a particular benefit in premium semi-permanent installations such as Broadway theaters and road shows.
DISPLAY2.1 (Direct SPL of ArraYs) is the software for configuring and optimizing MLA Compact — providing an accurate prediction of the direct sound produced over the audience as well as areas where sound should be avoided — generating precise frequency response and rigging information, including mechanical load safety analysis. DISPLAY2.1 interacts with onboard DSP, calculating the parameters for each driver and uploading them to each enclosure via the U-NET digital network.
The Venue Entry process begins by simply measuring and entering the room’s cross-section dimensions into the software and defining the audience listening area, along with the number of cabinets and their trim height. Next, Coverage Parameters are set by assigning non-audience as well as any “hard avoid” areas, front-to-back SPL variance in dBs and by entering temperature and humidity along with desired compensation.
Display 2.1 takes around three minutes to determine optimum array splay angles, and then another 5 to 20 minutes (depending on number of cabinets and venue size) to calculate 3200 parameters per enclosure, which can be performed while the arrays are being rigged. The software evaluates all possible configurations against target functions such as frequency response, flatness and sound leakage into non-audience areas. The custom preset is then uploaded to the networked arrays over VU-NET.
The ability to prioritize “hard avoid” areas can be powerful when operating outdoors under strict sound control regulations and in typical summer sheds and tents, where it provides significant improvements to sound quality by avoiding overhead roofs. In venues with high reverberation and other challenging acoustics, it also provides an advantage over traditional line arrays.
The greatest benefit is that the system consistently provides an even response throughout the listening area with a deviation as little a couple dB from front to back and a wider-than-usual stereo field. Not everyone can use a large-format MLA system, however Martin Audio’s MLA Compact opens the stage door to many vendors, designers and operators in theater, house of worship and touring who thought that MLA exceeded their needs or means.
