Key takeaway
Key takeaways
- T-5 weeks: Geometry capture
- T-3 weeks: Prediction and design issue
- T-2 weeks: Rigging approval
- Show day −1: Build and hang
How line array systems is actually delivered
A line array is a coverage engineering exercise, not a stack of boxes. We model the room or the ground in prediction software — Soundvision for L-Acoustics, ArrayCalc for d&b — using the actual seating geometry, trim height and surface materials. The output is a splay-angle schedule for each box in the hang, a rigging plot with point loads, and an SPL map that shows what the last row receives against the front row. The design target for speech-heavy and large-crowd work is coverage within about ±3 dB across the audience, with energy deliberately kept off ceilings, rear walls and any surface that returns a late reflection.
From enquiry to load-out
- T-5 weeks
Geometry capture
Site survey or drawing review to get trim heights, seating depth, surfaces and rigging capacity into the model.
- T-3 weeks
Prediction and design issue
Coverage map, splay schedule, rigging plot and point-load report go to the venue and the structural engineer.
- T-2 weeks
Rigging approval
Venue or structural sign-off on hang points, and generator and distribution coordination for delay positions.
- Show day −1
Build and hang
Motors, arrays, subs and delay towers go up; power and network are proved end to end.
- Show day, T-6 hours
Alignment
Smaart measurement at audience positions, delay timing with temperature correction, final EQ and limiter settings.
- Show +2 to +8 hours
Strike
Delay positions down first, main hangs last, with rigging de-rig supervised by the lead rigger.
Who is on site
- System designer
Builds the prediction model, sets splay angles and box counts, and signs the SPL map before anything is quoted.
- System engineer
Executes the design on site, measures with Smaart, times every delay position and owns the final alignment.
- Lead rigger
Verifies rigging points and load capacity, sets motors and load cells, and signs off before a hang leaves the ground.
- Amplification technician
Builds and monitors the amplifier racks, watches network and driver health, and manages redundant feed switching.
- Delay position technician
Builds, ballasts, powers and aligns the delay towers, then holds position during the show in case a feed drops.
What you should receive
Deliverables
- Soundvision or ArrayCalc coverage model with SPL prediction map
- Box-by-box splay angle schedule for every hang
- Rigging plot with point loads and bridle calculations
- Measured Smaart traces from the audience positions used for alignment
- Delay timing sheet with distances, computed delays and temperature correction
- Amplifier and network topology diagram showing redundancy paths
- Boundary noise measurement log against the venue condition
What we plan around
What can go wrong
How we prevent it
- What can go wrong
The venue's published rigging capacity turns out to be theoretical and will not take the hang.
How we prevent itWe require a point-load sign-off from the venue or a structural engineer at T-2 weeks, and keep a ground-support tower design as the fallback.
- What can go wrong
Delay towers are timed at noon and sound wrong at 9 pm as the air cools and the speed of sound drops.
How we prevent itDelays are computed with the forecast show-time temperature and re-measured just before doors, which typically moves each tower a fraction of a millisecond.
- What can go wrong
Low frequency from ground-stacked subs rolls straight into the nearest housing and triggers a complaint.
How we prevent itA cardioid or end-fire sub array cuts rearward output by 15 dB or more in the problem direction, measured at the boundary before the show.
- What can go wrong
Coverage is modelled for the drawn seating plan, then the client adds 1,500 chairs on the flanks the day before.
How we prevent itWe design the hang with outfill capacity in reserve and keep the splay schedule adjustable, so flank coverage is a change of angle rather than a change of system.
The detail that matters
Distance is solved with time, not volume. Beyond roughly 50 to 60 metres the direct sound from the main hang has lost too much level and high frequency to carry intelligibility, so we add delay positions. Each one is timed against the measured distance from the main array at the local speed of sound — about 2.9 milliseconds per metre, adjusted for air temperature, which moves measurably across a hot afternoon into a cool night. We usually add one to three milliseconds of extra delay so the main system still arrives first and the audience localises the stage rather than the tower beside them.
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Published 21 August 2026 by the Prime AV Solutions production team.