Several things affect the degree of toe-in a pair of speakers requires to produce a stable and precise image. The width of the baffles holding the drivers, the location of the speaker's own reflective surfaces, and the location of reflective surfaces in the room are all factors. Any sonic reflection from a large speaker baffle is 100% distortion and changing the angle of the reflection relative to the listening position will change the system's frequency response and sound.  The Vandersteen minimum baffle design effectively eliminates baffle and other structure based reflections leaving room surface reflections as the only toe-in factor. If the side walls are within 4 feet of the speakers, toeing-in the speakers can improve the image. When the speakers are toed-in, they should never be pointed directly at the listener.