Line Array Calibration & Subwoofer Steering Techniques

Acoustic Wavefront Coupling and Line Source Physics

A true line array relies on constructive acoustic interference to produce cylindrical wavefronts in the near-field. By properly configuring cabinet splay angles, system engineers can equalize sound pressure level (SPL) distribution so that audience members 150 feet away experience the same tonal balance as those 20 feet from the stage edge.

1. Vertical Splay Angle Optimization

The top elements of a hung line array focus energy toward the farthest balcony seats (tight 0.5° to 1° splay angles for maximum coupling), while bottom cabinets widen their splay angles (up to 7.5° or 10°) to cover close-up front row seats without overpowering them.

2. Cardioid Subwoofer Steering (Gradient vs End-Fire)

Omnidirectional sub-bass energy bouncing off rear stage walls destroys monitor clarity and muddy artist IEMs. Implementing cardioid sub configurations solves this issue:

• Gradient (Inverted Stack): Place the physical middle subwoofer facing backwards toward the stage. Invert its phase (180°) and apply time delay corresponding to the physical depth of the cabinet. This creates up to 25 dB of sub-bass cancellation on stage while reinforcing audience energy.
• End-Fire Array: Arrange rows of subwoofers sequentially from back to front, delaying rear elements to align perfectly with forward wavefronts.