I thought I'd share THIS article about line arrays. I'd read it in the past, came across it the other day and was reminded what a good article it was. It's written in layman's terms yet gives some depth on the technical aspects of a line array. I particularly like the "highway noise" example.
Also well done is the explanation that the physical array needs to be 4x the wavelength to exibit true line array properties of -3db fall off for every doubling of distance. I did some math with my litlte column speaker and it works out that I'm getting some of the aspects of an array at around 2000K, which agrees with the published specs.
Anyway just thought I'd share.