Line ArraysHANGING OUT IN MORE PLACES THAN EVER 1/01/2005 7:00 AM Eastern
In recent years, line array systems have garnered considerable attention as a means of addressing sound reinforcement requirements for medium- to large-size audiences. When properly designed and installed, line arrays do a good job of providing even and predictable sound coverage, making them a viable choice for performing theater, concerts, corporate events and shows. With the introduction of compact line arrays, these systems are also finding their way into smaller venues and houses of worship.
As line array systems are equally at home in professional touring and installed sound applications, several equipment manufacturers now offer modules (the individual enclosures that comprise an array) in multiple sizes. Between the size and the number of modules in any given array, considerable flexibility exists when planning your system.
Like everything else, line arrays have their pros and cons. A line array may not, for example, be the best choice in venues with low ceilings. And while a line array ground stack may competently address this environment, a more conventional delay speaker system could be a better choice. The audience, room dimensions, rigging requirements and staging/set considerations all play important roles in making this determination.
The paragraphs that follow should help you determine what's available. Nearly all manufacturers have detailed specs, application notes and/or white papers available on the Internet, so we've provided links to Websites for additional information.
Debuting at Summer NAMM last July, the AL10 is the larger of A-Line Acoustics' (www.a-lineacoustics.com) two line array models and features two 10-inch LF drivers coupled with a 1.4-inch HF driver providing 90° dispersion using the company's Line Source Replication technology for optimized projection and detail. The AL8 features two 8-inch LF drivers and employs the same HF driver (155° dispersion) as the AL10. The enclosures are constructed from birch plywood. Both models incorporate the company's EZAL
The SpekTrix Series from Adamson (www.adamsonproaudio.com) encompasses three models: the SpekTrix, SpekTrix Sub and the new SpekTrix Wave. Utilizing Adamson's AIR (Adamson Integrated Rigging) flying hardware, the SpekTrix Wave is a three-way design in a 15° trapezoidal enclosure. This module incorporates two Adamson 8.5-inch Kevlar neodymium drivers (one ND8-L mid-bass driver and one ND8-M midrange driver) and a 1-inch HF compression driver mounted on a patented Adamson wave-shaping sound chamber. The sound chamber has a defined coverage pattern of 15°×120° (V×H). The SpekTrix is similar in size, weight and components, but has a slightly narrower vertical dispersion pattern. The SpekTrix Sub is a compact, sub-bass loudspeaker with two AW18 Kevlar bass drivers mounted in a tuned, vented and fully braced cabinet. The Sub may be arrayed conventionally or for true cardioid performance. Adamson's Y-Axis line includes the Y10 sub-compact three-way module, the Y18 3-way module and the Y10 Sub, a flyable, front-loaded, dual 18-inch vented enclosure.
The LR14 from Alcons Audio (www.alconsaudio.com) is a passive two-way line array system incorporating dual 6.5-inch neodymium woofers and the company's RBN401 4-inch pro-ribbon driver on a 94-percent frontal radiation HempHorn
Apogee Sound's (www.apogeesound.com) bi-amped, two-way ALA-3 is the most compact of the ALA line. Each module incorporates two 10-inch cone-type drivers for the LF, coupled with dual 1-inch exit compression drivers for the HF. Frequency response is 65 to 17.5k Hz. Sharing the same compound trapezoid vented design but larger is the bi-amped, two-way ALA-5, which uses dual 15-inch cone-type drivers for the LF and two 1-inch exit compression drivers for the HF. Frequency response is 50 to 17.5k Hz. Designed for high SPL applications, Apogee's largest modules are the ALA-9. The tri-amped, three-way ALA-9 uses two 15-inch cone-type drivers for the LF, two 10-inch cone drivers for mids and three 2-inch exit compression drivers for the HF. The ALA-9's frequency response is 45 to 17.5k Hz. All three models are compatible with Apogee's DLC24 digital loudspeaker controller.
D.A.S. Audio's (www.dasaudio.com) Aero Series compact line array systems encompass five nonpowered models: the CA-28, CA-28B, CA-215, Aero-48 and the Aero-218Sub. There are also two powered models available: the CA-28A and the CA-215A. The CA-28 is a passive two-way module designed for use with external amplification and the company's CT-28V2 analog processor or dsp-3vs digital controller. Two 8-inch cone transducers incorporating neodymium magnetic assemblies and 2.5-inch voice coils are used for mid-frequency reproduction. High-frequency reproduction is handled by the company's M-10N medium-format compression driver using a 3-inch titanium diaphragm, copper-clad aluminum EFW voice coil and a 1.5-inch exit throat coupled to D.A.S. Audio's SERPIS high-frequency plane wave generator. The trapezoidal enclosure has a horizontal dispersion of 120°. The C-28A's power amplifier is a hybrid Class-D+AB rated at 350-watt MF/100W HF. The CA-28B is a two-way active, mid-high enclosure while the CA-215 is an unpowered subwoofer. The CA-215A offers a powered option and incorporates a 1,000W Class-D amplifier. The Aero-48 is a three-way system and the Aero-218Sub is a bass-reflex subwoofer with dual 18-inch transducers, all designed for use with external amplification and the dsp-3vs digital controller.
The Q1 line array loudspeaker from d&b audioteknik (www.dbaudio.com) is a passively crossed-over two-way system. Constant directivity is maintained using a large-frequency overlap through the crossover range. The recessed dipolar positioning of the two 10-inch low-frequency drivers mechanically time-aligns these with the 1.3-inch exit HF driver. The Q1 HF driver is fitted with a toroidal wave-shaping device, which has a 75°×15° (H×V) dispersion pattern; the resulting curved coherent wave front allows vertical arrays of multiple cabinets to be constructed. The Q7 loudspeaker uses the same 1.3-inch HF driver fitted to a rotatable 75°×40° (H×V) conventional constant-directivity horn allowing for it to be deployed as either flown or ground supported as single units, or as a near-field element within columns with Q1 cabinets. The Q10 is a 110°×40° passive two-way system housing two 10-inch LF drivers and a 1.3-inch HF compression driver with a rotatable constant-directivity horn. The Q-SUB cabinet completes the series, sharing the same width as the other loudspeakers. The Q-SUB is a bass-reflex design with an 18-inch long-excursion driver and can be used in Cardioid Subwoofer Arrays (CSA) when driven by d&b's D12 amplifier.
The KF760 Series from EAW (www.eaw.com) comprises the KF760 and KF761 three-way modules, and the BH760 subwoofer. The KF760 uses two horn-loaded 12-inch woofers for the LF, two horn-loaded 10-inch cones for the mids and two 2-inch exit/3-inch voice coil horn-loaded compression drivers for the HF. The KF761 uses two 12-inch horn-loaded woofers for the LF, two 8-inch slot-loaded cone-type drivers for the mids and one 2-inch exit/3-inch voice coil horn-loaded compression driver for the HF. Frequency response for an individual enclosure (both KF760 and KF761) is 80 to 16k Hz. The BH760 subwoofer uses two 12-inch woofers in a bent-horn design. Baltic birch plywood construction is used in all three models. The smaller KF730 Series incorporates two modules: the bi-amped KF730 and the SB730 subwoofer. A single MF/HF horn fills the entire face of the KF730 to maintain horizontal pattern control throughout the MF/HF passband. This module uses two 7-inch horn-loaded cone drivers for the mids and two 1-inch exit-compression drivers for the HF. Two side-mounted 10-inch cone drivers handle the LF. The SB730 subwoofer employs dual 12-inch cone drivers in a vented cabinet design.
The Electro-Voice (www.electrovoice.com) X-Line comprises four application-specific enclosures: the Xvls and Xvlt primary enclosures, the Xfil for downfill coverage and the Xsub deep-bass system. The Xvls and Xvlt enclosures are similar, but have differing directional specifications — the Xvls covers 90°, and 120° for the Xvlt. Each enclosure is a three-way configuration comprising two 15-inch woofers in a vented box enclosure for the LF, two 8-inch neodymium drivers on a 90° horn for the mids and three 3-inch-diameter titanium-diaphragm compression drivers on a 90° horn for the HF. The Xfil complements the Xvls and Xvlt systems for near-field assignment with a wide 120°×40° vertical coverage angle. The Xsub is a high-output, dual 18-inch woofers, 1,200W subwoofer system. The Xlc full-bandwidth compact line array system employs a very efficient rigging system for the Xlc127+ main enclosure and the Xlc118 direct radiating subwoofer. The Xlc127+ is a three-way, tri-amped, axis-asymmetric design with a passive crossover for bi-amp operation. A single 12-inch transducer handles the LF and mid bass, while two 6.5-inch drivers in a vertical array handle the mid-frequency bandpass. There are twin compression drivers for the HF. The Xlc118 subwoofer employs a single 18-inch subwoofer.
JBL's (www.jblpro.com) VerTec Series encompasses six models: the VT4887, VT4888 and VT4889 three-way systems; and the VT4880, VT4881 and VT4882 subwoofers. The compact VT4887 houses two 8-inch woofers, four 4-inch midrange radiators and two high-frequency compression drivers. The midsize VT4888 houses two 12-inch woofers, four 5.5-inch midrange radiators and two high-frequency compression drivers. The large-format VT4889 houses two 15-inch woofers, four 8-inch midrange radiators and three high-frequency compression drivers. These three-way models utilize a wedge frustum, 5° side-angle design. The VT4880 full-sized subwoofer houses two 18-inch woofers, and the new midsized VT4882 subwoofer holds a pair of 15-inch woofers. Finally, the VT4881 compact subwoofer houses a long-extension 15-inch woofer. All systems feature JBL's Differential Drive
The T Line line array system from KS Audio (www.ksaudio.com) is a two-way design with dispersion per module of 90°×5° and a frequency response of 60 to 19k Hz; the addition of the company's T Sub subwoofer extends the frequency response to 35 Hz. Each module is loaded with two 12-inch transducers and a 2-inch compression driver. Both types of drivers use neodymium magnets to ensure light weight and low distortion. The T Line sub-bass enclosure uses eight 10-inch LF drivers. KS Audio recommends the use of one T Sub with each array of four T Line modules. The T Line is powered by the KS audio TA4U 4-channel amplifier (1,000W @ 4 ohms per channel). Two channels in bi-amp mode can power two T Line cabinets. Two TA4U amplifiers, therefore, can power an eight-box array. The entire T Line module, including the captive flyware, weighs 96 pounds.
Unveiled in October at AES, L-Acoustics' (www.l-acoustics-us.com) new KUDO is an active, three-way line array module containing two direct-radiating, bass reflex-loaded 12-inch LF transducers, four 5-inch midrange frequency transducers mounted in a V-shaped configuration, and two 1-inch exit compression drivers coupled to individual waveguides. Frequency response for this full-range system is 50 to 18k Hz, with less than ±3dB variation — with the usable bandwidth being 40 to 20k Hz (-10 dB). Two DOSC waveguides are incorporated into KUDO, enabling the company's Wavefront Sculpture Technology (WST) to be performed either vertically or horizontally. KUDO also provides adjustable polar patterns. When installed horizontally as a constant-curvature line- source array, 10° inter-enclosure angles are employed and the horizontal coverage is 10°×N. (N is the number of enclosures.) Vertical directivity can then be configured as 55° or 110° (symmetric), as well as 25°×55° or 55°×25° (asymmetric).
The Martin Audio (www.martin-audio.com) W8LM is a mini line array enclosure designed for a variety of small- and medium-scale applications. Employing the company's constant-directivity horn design (also used in its W8L and W8LC line array systems), the W8LM is a three-way system with the company's Hybrid
The MLA3 is a low-profile, axially symmetrical, three-way line array module based on McCauley's (www.mccauley.com) MONARC line array technology. The MLA3 is designed to bridge the gap between the company's large-format MONARC MLA6 and the ultracompact M.LINE modules. The MONARC MLA3 mid-high section combines McCauley's Intercell Summation Aperture technology with two 8-inch HX32 cone drivers for the midrange and two 2-inch diaphragm drivers for the highs, all integrated into a single device. LF is managed by twin volumetrically loaded 12-inch transducers symmetrically arranged on either side of the Intercell Summation Aperture. The rigging system allows cells to be ground-stacked from the bumper for nonflown applications.
Encompassing the M1D, M1D-Sub, M2D, M2D-Sub, M3D, M3D-Sub and the MILO/MILO 120 systems, Meyer Sound's (www.meyersound.com) line array offerings are extensive. All M Series products are self-powered and feature the company's QuickFly
Nexo's (www.nexo-sa.com) line array offerings include the GEO S Series (S805/S830) and the GEO T Series T4805/2815 Tangent Array Modules. With the S805 and S830, each enclosure employs a single 8-inch neodymium LF driver and a 1-inch throat neodymium HF driver on a Hyperboloid Reflective Wavesource. This wavesource enables the 30° trapezoidal S830 and the 5° trapezoidal S805 to be arrayed tangentially. Frequency response for the S805/S830 enclosures is 67 to 19k Hz. The GEO T4805 employs a unique LF section that uses paired front- and rear-firing 8-inch neodymium woofers, processed with DSP algorithms to produce a cardioid pattern from 70 Hz to 250 Hz. The HF driver is a 1.4-inch throat neodymium with a 3-inch voice coil. Frequency response for the T4805 is 60 to 19k Hz. The T2815 controls mid-bass energy with a cardioid dipole that pairs the front-firing woofers with resistive acoustic radiators. When used as the near-field element in a curved vertical Tangent Array with T4805 modules, the T2815's passive radiators enable it to generate a 120° dispersion in the noncoupling plane from 77 Hz to 250 Hz. The T2815 can also be used stand-alone. Used with Nexo's NX242 Digital TD controller, GEO Series systems can be networked using the EtherSound protocol.
The FT.LA and FT.LA-P compact line arrays from PAS (www.pas-toc.com) are identical enclosures except that the FT.LA-P is the company's powered version. These two-way enclosures utilize a single 15-inch coaxial loudspeaker with a Kevlar-reinforced cone, and a 4-inch voice coil for the LF and a 2-inch compression driver for the HF. Both enclosures employ the company's Time Offset Correction
QSC's (www.qscaudio.com) ISIS WideLine is a full-range, wide-angle line array speaker system with a 140° horizontal dispersion pattern. Incorporating a selectable three-way, bi-amp or tri-amp design, the WideLine's internal midrange frequency shading can be switched to either of the two woofers. Both drivers handle the low frequencies, but only one driver handles the mids. The frequency-shading circuit enables the operator to redirect mid-bass buildup without touching the EQ for improved intelligibility in an otherwise problematic frequency range. Each WideLine element uses dual 10-inch, long-throw LF speakers in a ported trapezoidal enclosure. The high-frequency driver is a 1.4-inch exit (3-inch voice coil) neodymium compression driver, mounted on a proprietary multiple aperture diffraction slot waveguide. The enclosure's lightweight, cored-composite construction weighs only 70 pounds per element, with all rigging included.
Employing a two-point suspension system for easy assembly, the PN102/LA and PNX102/LA enclosures from Renkus-Heinz (www.renkus-heinz.com) share the same components, with the PN102/LA being self-powered. Both models provide 150° horizontal dispersion and have a frequency response of 50 to 18k Hz. These enclosures use two 1-inch exit HF drivers and two 10-inch woofers for the LF. The crossover point of these two-way systems is 1 kHz. The PN102/LA uses the company's PN-1 PowerNet amplifier rated at 300W RMS. STLA and STXLA line array modules are based on the company's CDT1.5 high-output CoEntrant driver with a 6.5-inch carbon-fiber cone for the mids and a neodymium HF driver with a 2.5-inch voice coil and titanium diaphragm. The enclosures use dual 12-inch woofers for the LF section. The STLA and STXLA provide 90° horizontal dispersion. Their frequency response is 45 to 18k Hz with crossover points of 500 kHz and 2,500 kHz. Renkus-Heinz line array systems include the company's AimWare software design tool.
Designed for large venues, the SLS (www.slsloudspeakers.com) RLA/1 incorporates multiple LS9900 three-way modules. The LS9900 comprises two 15-inch LF woofers, four 6.5-inch cone drivers for mid-range and two PRD1000 push-pull neodymium ribbon drivers for HF. The RLA/2 is designed for medium to small venues and utilizes multiple LS8800 modules. Each LS8800 employs two 8-inch high-powered woofers and the PRD1000 ribbon driver. The RLA/3 is a lightweight, compact line array comprising multiple LS6500 modules. Each LS6500 utilizes a 100W RMS, 6.5-inch woofer and an SLS PRD500 5-inch Planar Ribbon Driver in a compact bass-reflex trapezoid enclosure. Available in nonpowered and powered models, the LS8695 and the P-LS8695 employ eight 6.5-inch woofers coupled with nine PRD500 ribbon drivers. The P-LS8695 incorporates 24-bit, 96kHz DSP.
TCS Audio's (www.tcsaudio.com) TL1200 is a three-way, full-range tri-amplified line array element featuring two 12-inch neodymium transducers deployed in split-quadrant waveguides to minimize side lobing. Four 6-inch slot-loaded midrange drivers coupled between the LF and HF devices provide high coherence and intelligibility. HF has three 1-inch exit compression drivers mounted to the company's Pure Path Lens System, which is coupled to the mid-frequency horn. The Baltic birch plywood enclosures are finished with the Duratex external coating. Frequency response for the TL1200 is 78 to 18k Hz (±3 dB per single enclosure). A matching line array sub, the TL1200S, features dual 12-inch drivers. Response for the TL1200S is 35 Hz to 120 Hz (±3 dB per single enclosure). All drivers for the TL1200 and TL1200S subwoofer are manufactured by B&C Speakers. For rigging, the TL1200/TL1200S line array system features a proprietary quick-release pin system, designed and manufactured by ATM Flyware.
Founded 25 years ago, WorxAudio (www.worxaudio.com) offers the TL-V8, a high-efficiency, two-way compact line array. Dual 8-inch woofers coupled to an AIM (Acoustic Intergrading Module) minimize cone filtering. A 3-inch compression driver coupled to a proprietary FlatWave Former delivers highs over a predictable, controlled coverage area. Its multi-ply plywood enclosure is available unfinished or in white or dark gray catalyzed polyurethane. A custom rigging system offers versatile array options.
Roger Maycock is a freelance audio writer based in Los Angeles.
Sam Berkow knows more than a little about sound. As a partner (with Steve Sockey) in the New York City-based firm SIA Acoustics, he's consulted on the sonic performance of hundreds of studios and performance spaces. SIA also developed SIA Smaart, a standard acoustic measurement and sound system optimization software package used by audio pros worldwide.
Why use a line array rather than a conventional speaker enclosure?
Line arrays tend to work best in situations in which there is a long — rather than wide — throw or a challenging reverberant condition. The advantages of line arrays is that the directivity of the array comes from direct-radiating loudspeakers, so you eliminate the use of horns, which can have that nasal horn sound. Further, within limits, you can control the directivity via processing. The downside to line arrays can be when you need very wide coverage or a lot of control in the low frequencies where the waves get very long. In these cases, you typically require very long arrays and/or many clusters.
We like line array solutions because of the natural sound that can be achieved and for their dispersion characteristics, their controllability and the predictability of the array. For the touring industry, arrays are particularly useful because they're easy to rig. Small changes to the hanging configuration of the array can be made very easily. Obviously, in complex traditional arrays, the rigging is often more complicated and changes require much more time and effort. Lastly, we find that the tools available to predict the performance and physical characteristics of line arrays extremely useful in event/system planning.
What about using a ground-stacked line array as opposed to a more conventional delay speaker system in environments where there are low ceilings?
That can be a tough call. The problem with ground stacks is that all of your sound is at the front and with a low ceiling (12 to 14 feet), you can easily take people's heads off with the levels required to meet your throw. If you need consistent level over a long listening area in a low-ceiling environment, you might want to go with a distributed delay system. It all depends on the distribution of the audience and what the function of the sound system is.
One of the main reasons we like conventional delay speaker systems in rooms with low ceilings is for speech intelligibility. In these cases, we'll do more low-mid energy from the front and then just fill in with high-mid drivers that are distributed, either in the ceiling or from the side, using DSP to control delays and EQ. In general, I'm less inclined to look to line arrays as the solution in rooms under 12 feet with long-throw requirements. Another important consideration is that ground-stacking a line array often makes the rigging of specific/required angles much more difficult than in a flown situation.
What issues should one consider when choosing a line array system?
The first and most important consideration is the use of the system. Is it for speech, for music and for what type of music? How much low end do you need? How much power and how reverberant is the environment? A key goal with almost any sound system is to provide clarity by achieving a good direct-to-reverberant ratio. So when considering a loudspeaker system, the key questions become, “What is the horizontal and vertical dispersion you need?” Typically, line arrays range from about 70° to 120° wide (horizontal), with the vertical dispersion determined by the length of the array. Another question is, “How much power do they handle and how much directivity do you need at lower frequencies?” Examining the directivity at 125 Hz is very different than the directivity at 1 kHz, so this becomes a critical issue. This is a key difference in music and speech reproduction. Finally, line arrays are tools, and like any tools, they can be used well or poorly!