Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
I consider corner placement to be within 1/4λ through the passband. Basically within a couple feet for subs. For mains, like π cornerhorns, you want them to be snuggled into the corners as close as possible. The idea is to have a point source eminating from the apex.
There is also a distinction betwen subs and mains with respect to forward axis orientation. It's not very important for monopole subs because they are omnidirectional. Where it is good to angle the speakers inward 45° is when using mains that have constant directivity, and this is because it makes a very large "sweet spot".