Front center. For just trying raw data places.. i use fractions. ODD fractions. Measure the room. start cutting it up by thirds, fifths, sevenths, for 'crazy things like partial walls which makes everythiing more complicated, check both measurements.
Try to NOt allow one measurement to be an EVEN fraction of another one with these partials. Especially say a window well is a fourth from the speaker,when the wall itself is thirds...
I know you did not ask that stuff, but i volunteered it anyway.
Speakers on end of long rooms often work well at sevenths front to back with fifths across: that is one fifth from each side wall, and three fifths in-between.
This is ONE way to start, others exist.
Try to NOt allow one measurement to be an EVEN fraction of another one with these partials. Especially say a window well is a fourth from the speaker,when the wall itself is thirds...
I know you did not ask that stuff, but i volunteered it anyway.
Speakers on end of long rooms often work well at sevenths front to back with fifths across: that is one fifth from each side wall, and three fifths in-between.
This is ONE way to start, others exist.

