Update 7/19/14: You can download the newer version of the calculator here.
Bob McCarthy’s method for designing uncoupled speaker arrays can take a lot of guesswork out of using MAPP. To further streamline the process, I made a calculator that describes the relations between the parameters of speakers in uncoupled arrays.
The important parameters are the spacing of the elements (s), the splay of the elements (β), each element’s coverage (φ), the distance at which the coverage patterns of adjacent speakers overlap (D-Unity), and the distance at which three elements overlap (D-Max). For simplicity’s sake, I have made some intermediate parameters:
To find unity distance with known spacing and splay:
To find spacing with a known unity distance and splay:
To find maximum distance:
To find splay angle with know unity distance and spacing:
And something new in version 1.3: a calculator for distributing front fill along a curved stage, for instance, because here splay and spacing are linked.
Using the width of the stage’s arc and its height, along with speaker coverage and the unity distance (in this case the distance from the stage lip to the front row), the calculator finds the stage’s radius and calculates the spacing and splay together:
And that’s it. The calculator will probably be updated again soon, so email me at if you’d like the latest version.