[numb7rs]

Speaker directionality gets interesting once you get to arrangements for festivals and concerts. Ideally the audience should all be able to hear well, which is difficult to achieve over such a large area and with multiple sources.

But you also don't want the neighbours to complain about the thumping bass. A number of subwoofers pointing backwards, with the right phase delay, destructively interferes with the most offensive frequencies and reduces the sound intensity behind the stage. It's called a 'cardiod' arrangement, because of the shape of the resulting sound intensity distribution.

[mannyv]

Larger venus also have a problem with delay, since longer runs are needed. I can’t remember how they deal with that though.

[ano-ther]

Yes. And then you have the vexing problem of the stage sound where you want the musicians to hear themselves and each other. Without feeding back into their microphones, and not too loud please.

Modern in-ear monitoring has solved some of this, but it’s still tricky (and expensive).