I have no window dressings on that window (shades or curtains) and the bass boxes are about five feet behind the lowther front horns. The bay windows seem to add a little reinforcement to the bass, which is good in my case since the sound needs to travel farther and so loses volume. About twenty-five feet out is the sweet spot in this configuration.

Using the true complete Pi cornerhorn instead of lowthers, a simple voltage divider in the crossover should allow you to play with the volumes if you need to do so.

Len