Martin Audio MLA User Manual page 26

MLA System
USER GUIDE
Early proponents of touring line arrays strongly advocated a flat wavefront from each individual HF element. However, our
sophisticated in-house BEM (Boundary Element Method) modelling techniques have shown that slightly curved wavefronts
deliver much more consistent SPL's to the audience in real-world use where the array is curved.
BEM models of a conventional horn show that the waveform expands as its travels down the horn to produce a convex vertical
wavefront which would generally be too curved for an ideal array element. Placing a kite shaped "wedge"part-way down the
horn* introduces a concavity in the waveform which compensates for this.
MLA System User Guide V2.1
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