The compact line array is often an excellent choice for sound reinforcement in small / medium venues. Almost all of the major line-array manufacturers also produce more compact versions of their technology, but what’s available at the moment?
Compact line arrays are no longer a new phenomenon, developed to provide the benefits of their larger cousins to smaller venues by reducing size, weight and cost.
There are also acoustic limits to using line arrays indoors or in small venues. Compact enclosures are not only cheaper and lighter, they are easier to curve in an array. The coupling effect, which is what makes a line array work, limits how much angle can be placed between each element of the array to about 5 degrees.
Smaller line array cabinets can bend in arrays for more vertical coverage in a shorter height. In a smaller space it’s not unusual to need 20 degrees of up tilt at the top of the array and more to get down to the front of the audience. You may need ten cabinets arrayed at 5 degrees each to achieve that coverage, which at 30cm a unit for a full sized system is a big array.
The downside of compact solutions is of course that the elements are not full range. They need supplementing with specially designed bass units that can be either flown with the array or floor stacked. Whilst manufacturers generally recommend arrays of a minimum of 4-6 elements that’s not to say that they can’t be used individually and short arrays are suitable as delay zones in larger distributed systems. Another possible use of individual elements is as balcony under-fills due to their small size and wide horizontal dispersion.
The compact options on the market right now are divided between the active and passive camps, with some available as both powered and passive versions.
Active ranges
Despite increases in the popularity of active solutions, there are still fewer available. The newest of these was introduced in January by EAW at the NAMM show. The NTL720 is a three-way line array module using some pretty clever design to fit a complex system of drivers into a small package. The company has crammed a full-sized mid/high horn, two six–inch cone woofers for the MF, and two side firing, 6-inch LF woofers in to a unit 60cm wide.
Achieving this has required innovative layout and built in DSP to compensate. There are diamond-shaped cut-outs in the horn to serve the MF drivers, these were so-shaped to reduce the loss of energy from the HF drivers. The DSP is matched to the three Class-D amplifier modules built into each element.
EAW have distilled new developments from several recent products into the smallest form to deliver full range performance in a compact chassis.
RCF’s TT range of powered systems includes the TTL33A and TTL31A line array elements. These are three and two-way systems designed for the theatre market. They include 24-bit floating point DSP, with considerable overhead in the processing power. The TTL33-A is powered by 3 class D amplifiers running at 500-watts for the mid-bass, 500-watts for the midrange and a 250-watt compression driver. They are all driven by a 750 watt switching power supply. The TTL31A features a 500 watt mid-bass and 250 watt compression driver. All of the processing and amplification is housed outside the elements for good heat dissipation.
No discussion of powered loudspeakers would be complete without a mention of Meyer Sound who have been amongst the pioneers of the technology. M1D is what the company terms an ultracompact curvilinear array loudspeaker. In other words, a compact line array. The system allows for splays of 0 to 8 degrees between elements and operating frequencies of 60Hz – 18kHz. Two 5-inch cone drivers and three ¾-inch HF metal dome tweeters make up the loudspeaker component and the M1D incorporates a 500 Watt power amplifier featuring active crossover and optimised phase response and frequency correction circuitry.
As with many of the competitive products, M1D is accompanied by monitoring software, Meyer Sound’s RMS, allowing the operating parameters to be monitored over a network using a PC or laptop.
Also in the powered domain is D.A.S.’s Variant solution. This is aimed squarely at the market for discrete, compact systems in houses of worship, theatres and corporate events. Consisting of three models, the 25A, 112A and the 18A subwoofer. The 25A features a pair of 5†MF drivers and a 1†HF driver. 112A is the bigger brother with a 12†MF and a pair of 1†tweeters. It also has a bigger internal amp to reflect this, at 500W for the MF unit and 100W for the high end. The 18A subwoofer houses a single 18†driver powered by a 1250W continuous (2500W peak) class-D amplifier. The 112A can be employed as a full range range, whilst the 25A is best off paired with the 18A or employed as a front fill or in multi-box arrays for small to medium installations.
Passive models
Passive solutions are still the more popular in sound installations. They are typically less costly than their powered cousins and the absence of a power amplifier means they can be smaller and lighter, two of the key advantages of compact arrays.
April 2007 saw QSC’s second entry into the compact market place with Wideline-8, a smaller sibling to Wideline-10. The elements are only just over 50cm wide and the system consists of WL3082 tri-amplified elements and the WL212-sw subwoofer. The WL3082 is a double 8†unit with single 3†compression driver for the high end which can be rigged in arrays of up to 12 units. They use a 140º wave-guide giving unusually wide horizontal coverage for such a compact system. The sub unit is a dual 12†in another very small enclosure producing peak SPL of 135 dB and LF extension to 32Hz.
Another new entry to the compact, passive space is Martin Audio’s Omniline, this diverges from the norm of simply shrinking a big live sound array into a more compact package. Omniline was developed very much with architectural and installed sound in mind, and an array of 4 to 32 modules can be adopted depending on the application. The company is pitching it at a huge range of applications, from transport to houses of worship – anywhere you might consider using a steerable column array. Full details of the principles of its operation are on Martin Audio’s site.
Martin also has a more traditional compact line array offering in the shape of the W8LM Mini line array. This is intended to fulfil the need for a versatile system to be flown or stacked at corporate events, or in theatres and other indoor venues. Dual 8-inch drivers and twin 1-inch HF units make up the loudspeaker assembly and with 120hm system impedance you can run up to four cabinets from a single amplifier channel.
One of the granddaddies of line array design is Electro-Voice. It’s take on the compact conundrum is the XLC, a full bandwidth line array in a compact chassis. There is also a variant design specially for fixed installation, the XLCi. The installation version features different mounting hardware tailored to the fixed install market. Although the product was first announced a few years ago now, it has been continually updated - the latest revision using EV’s latest DVX transducers. The core units are the XLC 118i subwoofer, the XLC 127i main enclosure and the XLC215i sub-bass. Unlike many systems the XLC is an axis-asymmetrical design, which the company says solves many of the problems associated with symmetrical solutions such as dead spots in the horizontal plane, known as lobing.
The three-way, tri-amped, design includes a passive crossover for bi-amp operation, if necessary. A single 12†speaker is used for the low-frequency section, two 6.5†custom-designed drivers in a vertical array comprise the mid-frequency bandpass. HF comes from a pair of ND6-Hydra transducers.
The dV-DOSC is the entry in this group from L-Acoustics, the French company credited with launching the current line array trend. The cabinet incorporates trademark Wavefront Sculpture Technology, the original technique for creating the flattened “plane wave†necessary to make modular line array technology work properly. It too falls into the “double-eight†category with a pair of 8†drivers and a 3†compression unit. The modules feature 120’ dispersion. L-Acoustics also offers the new Kiva solution, with it’s accompanying sub unit, Kilo. Kiva is even smaller than the dV-DOSC, packing two 6.5†and a single 1.5†driver. Additionally it can be rigged at angles of up to 15° between elements, allowing smaller arrays to be constructed.
JBL gets in on the installed sound act a new version of its established Vertec system. The VT4887 is a bi-amped, three-way element, which the company says is designed to deliver high-quality speech and music reinforcement for corporate A/V presentations as well as other venue installations. The unit features two 8†woofers, mid-range 4†radiators and to HF compression drivers.
Last but not least on the passive compact pile is Nexo’s S8. The system contains the S805, which is the basic line array element and the S830, which is the accompanying tangent array module. The 805 unit features an 8†long excursion woofer and a 1†exit neodymium driver. Interesting the S8 series also features a configurable directivity flange which can be set at either 80 or 120 degree dispersion depending on what the installation requires.
An array of arrays
As you can see, the compact space is now a very cluttered one. All the manufacturers have seen the demand for smaller solutions that bring the line array effect to the convention centre and house of worship market. The double-eight arrangement is currently the most popular, providing a good trade-off between power, size and price. Within that, you pays your money and takes your choice. Sound has always been highly subjective, so once you’ve selected based on features and price, it’s really down to what your customer believes sounds best.