Even the 1/3 WL spacing center-to-center is a tall order given the mouth sizes of most midbass/midrange horns with a single driver (assuming they're being tightly arrayed). With baffle-mounted cones in a vertical array, I'd need a stack of differing diameters to cover the ranges up to the typical 1" horn/driver combo. This challenges one of my goals for each design: a 3-way active system (triamp with active x-over/processing). As my design ideas are aimed toward live sound reinforcement, I will likely see how often and to what extent I can "cheat" the C-to-C coupling guidelines, with as little compromise to sound quality as possible. In many live applications, the listeners are farther away from the audio source than with a home system, meaning more room to squirm for the live audio designer!

In the case of crossover between horns that cover different bands, the region of interest is the overlap region. If the spacing between sound sources is within 1/4λ through the overlap region, then the two sources will act as a single sound source.

In any event, if sound sources are too numerous to allow for tight pack spacing, then the next choice is dense interference. There are merits in this approach, as it smooths the sound field even though spacing is further than 1/4λ, and often times further than 1λ. Another thing that results from this approach is it tends to smooth out the nulls that result from reflections in the environment.