Line Array Basics: Understanding Modern PA Systems

Line arrays have become the dominant PA technology for medium to large venues, offering controlled coverage, extended throw, and predictable performance. Understanding line array principles helps in selecting, deploying, and operating these systems effectively.

What Makes a Line Array

Line arrays consist of multiple identical speaker cabinets arranged in a vertical line. The cabinets couple acoustically, behaving as a single extended source rather than individual speakers.

For coupling to work, speakers must be close together—typically touching or nearly touching—and operating in phase. The combined output creates a coherent wavefront.

Each cabinet covers a narrow vertical slice of the audience. The combined array covers from front to back with consistent level.

How Line Arrays Differ

Point source speakers radiate sound spherically, losing 6 dB each time distance doubles. Line arrays approach cylindrical radiation, losing only 3 dB per doubling in their coupling range.

This slower attenuation allows line arrays to cover greater distances with more consistent level from front to back.

The narrow vertical pattern reduces floor and ceiling reflections, improving clarity in reverberant spaces.

Array Configuration

Line array boxes typically angle relative to each other, creating a curved configuration. The top boxes aim furthest, covering rear audience areas; bottom boxes aim more steeply for front coverage.

Software from manufacturers (JBL Performance Manager, d&b ArrayCalc, L-Acoustics Soundvision) calculates optimal angles based on venue geometry.

Flown arrays hang from rigging points, allowing steeper angles than ground-stacked configurations. Flying enables the full range of array configurations.

Common Line Array Brands

JBL VTX and VRX series serve touring and installed applications. The VTX A8 and A12 represent current flagship technology.

L-Acoustics K series and A series have become industry standards for touring productions. The L-Acoustics KARA is ubiquitous in medium-format touring.

d&b audiotechnik, Meyer Sound, and Electro-Voice also produce widely-used line array systems.

Rigging Fundamentals

Line arrays require proper rigging for safe flying. Purpose-built rigging hardware from the manufacturer ensures correct angles and secure connections.

Weight calculations must account for dynamic loads during movement. Certified riggers should supervise all flown array installations.

Ground stacking reduces rigging complexity but limits array configurations and optimal coverage patterns.

Subwoofer Integration

Line array systems typically pair with separate subwoofers for low-frequency reproduction. The main array handles mid and high frequencies.

Subwoofer configurations vary—ground stacked, flown alongside arrays, or positioned in cardioid arrangements for directional bass.

Processing coordinates subwoofer and array output, managing crossover, delay, and level relationships.

When Line Arrays Make Sense

Medium to large venues with significant throw distances benefit from line array characteristics. Festival stages, arenas, and large theaters suit line arrays well.

Reverberant spaces benefit from line array pattern control, reducing unwanted ceiling and wall reflections.

Applications requiring consistent coverage from front to back—where front row and back row should hear similar levels—favor line arrays.

When Point Source Works Better

Small venues often do not benefit from line arrays. The boxes may be too large, and the throw advantages do not materialize in short distances.

Applications with limited rigging capability may prevent flying arrays optimally. Ground-stacked line arrays sacrifice many line array advantages.

Budget constraints may favor point source systems that deliver more output per dollar in applications where line array advantages do not apply.

Powered vs Passive Line Arrays

Powered line arrays like QSC KLA or JBL VRX include amplification in each box. Simplified setup trades against increased weight per box.

Passive line arrays with external amplification remain common for touring applications. Dedicated amplifiers and processing (d&b D80, L-Acoustics LA12X) drive the system.

Powered arrays suit rental and portable applications; passive arrays with rack systems suit permanent installations and touring productions with infrastructure support.

System Processing

Line array systems require system processing for optimal performance. Preset-based processors load configurations specific to the array and application.

Lake, BSS, and manufacturer-specific processors (L-Acoustics LA Network, d&b DS10) provide crossover, limiting, delay, and EQ functions.

Following manufacturer processing recommendations ensures the system performs as designed. Deviation from presets may void warranties or damage components.

Array Operation

Array systems require more setup expertise than point source speakers. Software prediction, precise rigging, and careful tuning reward the complexity.

System engineers familiar with specific line array brands achieve best results. The learning curve for new systems can be significant.

Rental houses and production companies typically provide trained technicians alongside line array rentals.