But here is the thing to consider with HD. With HD I can point the speakers such that the early reflections are minimizes and so that the first reflections come to the ear opposite the first arrival. This is very important since a first arrival and an early refelction at the same ear will cause coloration. This is point one.

Now also consider the energy time arrival of an HD versus a LD. The LD reflections arrive almsot instantaneously there is not gap between the first arrial and the early reflections. Not so the HD. There is a significant gap between the first arrival and the early reflections. I cannot overstate how important this later aspect is to imaging. Without a gap in the arrival times of the direct sound and the early reflectiosn the ear cannot resolve spatial location cues and the imaging will be poor.

The imaging on my speakers is as precise as headphones but without the "in the head" image problem. Pinpoint locailzation in a space beyond the actual location of the speakers. It really has to be heard to be believed.