Distributed Speaker Systems: Even Coverage Approaches

Distributed speaker systems use multiple speakers throughout a venue rather than relying on a central cluster. This approach provides even coverage, consistent level, and natural sound in spaces where point-source systems struggle.

When Distribution Works Better

Large, reverberant spaces benefit from distributed systems. Sound from a central source reflects multiple times before reaching listeners, creating intelligibility problems.

Distributed speakers place sources closer to listeners, reducing the ratio of direct to reverberant sound. Listeners hear more direct signal and less room reflection.

Low ceiling venues challenge central speaker placement. Distributed systems mount in the ceiling, providing coverage without requiring high placement.

Types of Distributed Systems

Ceiling speaker systems use multiple small speakers in a grid pattern. Each speaker covers a limited area; the combination covers the room.

Column speaker systems use multiple speakers along walls or mounted on posts, each covering a zone of the space.

Delay ring systems use conventional speakers positioned at increasing distances from the stage, each delayed to maintain source localization.

70V/100V Systems

Constant voltage (70V or 100V) systems simplify distributed installations. Multiple speakers connect to a single amplifier run, with transformers at each speaker setting individual levels.

This approach reduces wiring complexity compared to low-impedance systems where each speaker needs dedicated amplifier channels.

70V systems suit background music and paging applications. For higher-fidelity music reinforcement, low-impedance distributed systems may perform better.

Zone-Based Control

Distributed systems often divide into zones, each with independent level control. This allows tailoring coverage to different areas’ needs.

Restaurant zones might adjust for busier or quieter sections. Conference facilities zone for different room configurations.

Zone control happens at the amplifier or processor level, routing content to appropriate speaker groups.

Delay Considerations

Speakers at different distances from a common source (stage or recording) need different delays to maintain coherent sound.

Rear speakers delay more than front speakers. Each zone’s delay aligns with its distance from the source.

Without proper delay, distributed systems create echoes or reduce intelligibility as arrivals from different speakers interfere.

Coverage Design

Speaker spacing depends on coverage angle and mounting height. Wider-dispersion speakers can space further apart; narrower patterns require closer spacing.

The “edge-to-edge” method spaces speakers so each unit’s coverage reaches the next speaker’s location. This provides consistent level with minimal overlap.

Ceiling height determines optimal spacing. Higher ceilings allow wider spacing; lower ceilings require speakers closer together.

Speaker Selection

Ceiling speakers for distributed systems typically feature wide dispersion (90-180 degrees) to maximize coverage from each unit.

JBL Control series, QSC AD-C series, and Electro-Voice EVID ceiling speakers suit distributed installations.

Pendant-mount speakers hang from ceilings where recessed installation is impractical, providing similar coverage in a different form factor.

Processing for Distributed Systems

System processors manage zoning, delay, and equalization for distributed speaker systems. BSS, QSC Q-SYS, and Biamp Tesira handle complex distributed processing.

Each speaker zone may receive different processing—EQ for speaker and room response, delay for alignment, limiting for protection.

Distributed systems benefit from measurement-based tuning of each zone to achieve consistent response throughout the venue.

Level Consistency

Distributed systems aim for consistent SPL throughout the coverage area. Listeners should experience similar volume regardless of position.

Level tapering—gradually reducing output from zone to zone—prevents buildup where zones overlap.

Measurement at multiple positions verifies consistent coverage. Walking the space during commissioning identifies hot or dead spots.

Live Sound Applications

Distributed systems in live sound most commonly appear as delay systems extending main PA coverage.

Some venues use hybrid approaches—point source mains for front sections with distributed delays for distant or shadowed areas.

Festival and outdoor stages may use delay towers—groups of speakers on elevated platforms positioned throughout large audience areas.

Installation Considerations

Distributed systems require significant infrastructure—speaker mounting, cable runs, amplifier racks, and processing.

Permanent installations plan these elements during construction. Portable applications for touring require quick deployment solutions.

Pre-wired venues simplify temporary distributed system installation. Many conference centers and arenas provide infrastructure for visiting productions.

Balancing Coverage vs Localization

Distributed systems trade localization for coverage. Sound appears to come from nearby speakers rather than a distant stage.

For speech intelligibility, this tradeoff often favors distribution. Hearing words clearly matters more than perceiving direction.

For musical performance, localization may matter more. Careful delay and level setting helps maintain stage as the perceived source.