John
If they are near fields they should be at ear level. A near field has a very narrow dispersion field. They should be pointed to the point where your head is. The ideal is a triangle where the near fields position form the base line and your head is at the apex.
There's probably something more ideal than this ideal.
Let us put things into perspective here; Any three points form a triangle and the three apexes are are called apexes.
If you define a line between two points as a baseline, a third point placed anywhere in Cartesian space that isn't on that line (and its linear projection) will form a triangle.
Placing the speakers and the listening position (a.k.a. your ears) in the formation of an
Isosceles triangle is traditionally thought of as nearly ideal.
Some people regard an
Equilateral triangle ( a subset of the Isosceles set) as an ideal.
As an example of an equilateral triangle layout; If the line formed by the speakers is 3 feet from driver to driver than the listening position will be 2.598 feet measured perpendicularly from the center of that 3 foot "line".
I don't have strong opinion about what sort of Isosceles triangle that I use. I tend to gravitate to something close to an Equilateral choice or sometimes a layout where the
vertex angle is smaller than the
base angles. If the vertex angle is much wider than the base angles the stereo spread can become unnaturally wide. I think that consideration of proximity to side walls should be incorporated into the decision with a desire to keep as much distance between the speakers and the side walls as practical or possible. In many cases a regard for proximity to the side walls will preclude a placement where the vertex angle at the listening position will be wider than 60*. In the end it just depends on where the listener places their head. If you start with an Isosceles triangle layout you can move forward and hear the stereo "spread" wider or move backward and hear the stereo "blend".
Turn it up!!!