Calculator Inputs
Use the fields below to estimate output level, aiming angle, transition distance, and coverage suitability for a flown line array.
Example Data Table
The sample below shows how the calculator behaves with typical mid-size venue assumptions.
| Cabinets | Cabinet Height | Splay | Power per Cabinet | Frequency | Listener Distance | Predicted SPL | Aim Angle | Coverage Margin |
|---|---|---|---|---|---|---|---|---|
| 8 | 0.35 m | 4.0° | 400 W | 1,000 Hz | 20.0 m | 118.43 dB | 17.86° | -5.09° |
Formula Used
1) Array length
Array Length = (Number of Cabinets × Cabinet Height) + ((Number of Cabinets − 1) × Gap)
2) Wavelength
Wavelength = Speed of Sound ÷ Frequency
3) Near/Far transition distance
Transition Distance = 2 × (Array Length²) ÷ Wavelength
4) Single cabinet maximum SPL
Single Cabinet Max SPL = Sensitivity + 10 × log10(Power per Cabinet)
5) Practical array gain
Effective Elements = 1 + ((Cabinets − 1) × Coupling Efficiency)
Array Gain = 10 × log10(Effective Elements)
6) Array maximum SPL at 1 meter
Array Max SPL at 1 m = Single Cabinet Max SPL + Array Gain
7) Propagation loss
If the listener is inside the transition distance, the calculator uses a cylindrical style estimate:
Loss = 10 × log10(Distance)
If the listener is beyond the transition distance, the calculator uses a mixed estimate:
Loss = 10 × log10(Transition Distance) + 20 × log10(Distance ÷ Transition Distance)
8) Predicted SPL at listener
Predicted SPL = Array Max SPL at 1 m − Distance Loss
9) Vertical audience window
Audience Window = |atan(Height Difference ÷ Front Distance) − atan(Height Difference ÷ Rear Distance)|
10) Mechanical arc
Mechanical Arc = (Cabinets − 1) × Average Splay Angle
Coverage is considered favorable when mechanical arc is equal to or greater than the audience vertical window.
How to Use This Calculator
- Enter the number of cabinets in a single flown array.
- Provide cabinet height, inter-cabinet gap, and average splay angle.
- Add the cabinet sensitivity and expected RMS power per cabinet.
- Choose a coupling efficiency value to reflect real-world summation quality.
- Set the design frequency for the wavelength and transition calculation.
- Enter listener distance, trim height, ear height, and audience depth.
- Set the target SPL at the listening point.
- Press Calculate Line Array to show the result summary above the form.
- Review predicted SPL, aiming angle, coverage margin, and required power.
- Use the CSV and PDF buttons to save the result set.
Frequently Asked Questions
1) What does this calculator estimate?
It estimates line array length, predicted SPL, aiming angle, transition distance, audience window, and the power required to meet a chosen target level.
2) Is the predicted SPL exact?
No. The result is a practical engineering estimate. Room reflections, processor settings, weather, enclosure design, and frequency response will change the final real-world outcome.
3) Why is coupling efficiency included?
Cabinets rarely sum perfectly in real venues. Coupling efficiency lets you apply a realistic de-rating so the estimate stays conservative and more useful for planning.
4) What does transition distance mean?
It is the approximate boundary where the array behavior shifts from more line-like propagation toward more point-source-like loss behavior at the selected frequency.
5) Can I use this for subwoofer arrays?
Not directly. Subwoofer arrays need different spacing, summation, and directivity assumptions. This calculator is designed for vertical line array planning, not low-frequency sub systems.
6) How should I choose the design frequency?
Pick a frequency that matters for speech clarity or coverage planning. Many users choose a midband reference where array control and intelligibility are important.
7) Why compare mechanical arc with audience window?
That comparison helps you judge whether the hang has enough curvature to cover the front and rear seating angles without obvious vertical under-coverage.
8) Should this replace manufacturer prediction software?
No. Use this tool for fast concept checks. Final deployment should still be verified with manufacturer software, rigging data, venue drawings, and qualified system design review.