Truss Lighting roundup
Truss Lighting: A Complete Buyer's Guide
Choosing a truss lighting system involves more decisions than most buyers anticipate. Beyond selecting fixtures, you need to match the truss structure to the venue, the rigging method to the available ceiling infrastructure and the control system to the fixtures. This guide covers the key purchase decisions in the order they should be made.
Start with the Structural Specification
Before selecting any fixtures, define the truss specification. The critical variables are the span between support points, the total weight of fixtures and accessories, and the maximum height the truss will be installed at. A longer span demands a higher-capacity truss section; a heavier fixture load demands either a stronger section or additional support points. Most manufacturers publish load tables that show permitted load per metre at common spans — match your calculated load against those tables before purchasing. A qualified structural engineer or certified rigger should review the specification for any suspended installation. For a technical overview of how truss lighting works, see the full overview.
Box Truss Versus Triangular Truss
Box truss (square cross-section, four-chord construction) offers higher load ratings per unit of length and integrates well with standard conical connector systems used by most major manufacturers. Triangular truss is lighter and less expensive, suited to ground-supported applications with lower total loads. For any suspended application over 4 metres in height carrying professional fixtures, box truss is the appropriate choice. Common cross-sections are 220mm and 290mm — the larger section provides greater load capacity and is standard for touring and installation rigs.
Ground Support Versus Ceiling Rigging
If the venue has no ceiling rigging infrastructure, a ground support system — upright towers with base plates carrying horizontal truss runs — is the practical choice. Ground support systems are self-contained, require no ceiling fixings and can be moved between venues. The trade-off is floor space consumed by the uprights and base plates, and a lower effective height than ceiling-rigged systems. For permanent or semi-permanent installations in venues with structural ceiling beams, ceiling rigging with chain motors gives greater height and leaves the floor unobstructed. For beginner advice on practical setup steps, see the beginner's guide.
Selecting the Fixtures
The fixture selection follows from the creative brief and the physical constraints. PAR cans and LED wash fixtures provide colour wash and general illumination at low fixture weight. Profile (leko) fixtures provide a precise beam with a sharp edge for gobos, texture and aerial effects. Moving head fixtures provide automated pan, tilt, colour and beam control from a fixed suspension point. A typical truss lighting rig combines wash fixtures for general coverage with one or two moving heads for emphasis and dynamic effects. Match fixture weight against truss load capacity when making selections — a single moving head can weigh 8–15kg, which compounds quickly across a full rig.
Control Systems
All professional fixtures are controlled via DMX512, the standard lighting control protocol. A DMX controller — either a hardware console or software running on a laptop with a USB DMX interface — transmits data down a daisy-chained cable run to each fixture. Each fixture is assigned a starting DMX address, and the controller addresses that channel range to operate the fixture. Simple rigs can be operated from a basic two-universe console; complex rigs with moving heads, fog machines and LED tape may require four or more universes and a full lighting console. Budget for both the controller and the DMX cabling when planning the overall system.
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