Line Array Speaker Design Basics

By Priya Nair · September 28, 2026

What Makes a Line Array Different

A line array is a vertical column of loudspeakers designed to couple coherently, producing a cylindrical wavefront that decays at 3 dB per doubling of distance (versus 6 dB for a point source). This gives even coverage from front to back in large venues.

The Line Source Principle

When speakers are stacked closely enough (spacing less than half a wavelength), they behave as a single continuous source. This creates constructive interference on-axis and destructive interference above and below — narrowing vertical dispersion while maintaining wide horizontal coverage.

Frequency-Dependent Behavior

High frequencies: Naturally directional due to small wavelengths. Waveguides further control dispersion.
Mid frequencies: Controlled by cabinet spacing and baffle width.
Low frequencies: Require many elements to achieve coupling — the reason line arrays are tall.

Waveguide Design

Modern line arrays use isophasic waveguides (L-Acoustics DOSC, JBL RBI) to ensure that high-frequency energy from a single compression driver arrives at all points across the waveguide exit simultaneously. This maintains coherent summation across the array.

Splay Angles and Coverage

Each cabinet in a line array connects at an adjustable angle (splay). Tighter splay angles narrow vertical coverage and increase throw distance; wider angles spread energy over shorter distances.

Prediction Software

Tools like L-Acoustics Soundvision, d&b ArrayCalc, and JBL LAC model array behavior before rigging. Engineers input venue dimensions, audience areas, and SPL targets, then the software calculates optimal splay angles.

Subwoofer Integration

Line arrays don't reproduce deep bass effectively — most systems roll off below 50–60 Hz. Subwoofer arrays (ground-stacked or flown) fill in the bottom end. Cardioid sub configurations reduce bass energy on stage while reinforcing it in the audience.

Practical Considerations

Rigging weight: Each cabinet can weigh 50–100 kg. Structural engineering review is required for flown arrays.
Power: Active arrays need dedicated power circuits. Passive arrays require matched amplifiers with DSP.
Weather protection: Outdoor events need IP-rated enclosures.