Tools
Lateral Aspect Ratio Calculator
Calculate frontfill loudspeaker spacing using Bob McCarthy's LAR formula
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Calculate frontfill loudspeaker spacing using Bob McCarthy's LAR formula
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| # | Distance |
|---|---|
| 1 | 0.00m |
| 2 | 1.70m |
| 3 | 3.39m |
| 4 | 5.09m |
| 5 | 6.79m |
| 6 | 8.49m |
| # | Position |
|---|---|
| 1 | 0.66m |
| 2 | 2.36m |
| 3 | 4.05m |
| 4 | 5.75m |
| 5 | 7.45m |
| 6 | 9.14m |
| 7 | 10.84m |
| 8 | 12.54m |
| 9 | 14.24m |
| 10 | 15.93m |
| 11 | 17.63m |
The Lateral Aspect Ratio (LAR) formula, developed by Bob '6o6' McCarthy, calculates the coverage width of a loudspeaker at a given distance based on its horizontal dispersion angle:
LAR = 2 × sin(Dispersion Angle / 2)
Coverage Width = Distance × LAR
The formula uses sine (not tangent) because loudspeaker coverage angles are defined by the -6dB contour, which forms an arc at constant radial distance from the source. For consistent coverage across the audience, adjacent loudspeakers should be spaced so their -6dB points overlap. This calculator determines the optimal spacing and positions for frontfill loudspeakers along a stage edge.
Reference: McCarthy, Bob. Sound Systems: Design and Optimization