Magnepan MG 3.6 - Manual (Page 8)

Figure 5
STEREO WIDTH AND IMAGING
Once you have located the best position for the speakers and your chair for
good bass performance, separate the tweeters by 50% of the distance from your
chair to the speakers. (For example, if your chair is 10 feet from the speakers,
move the tweeters 5 feet apart.) Now move the speaker apart in increments of 3
or 4 inches at a time, listening carefully at each position. At some point you will
start to hear two separate speakers instead of getting a "stage effect" (or
continuous image). If you have a hole-in-the-middle effect, your speakers are
too far apart: begin moving the speakers closer together in small increments
until you notice a point at which you achieve one cohesive "sound stage." See
Figure 3 or 4.
A small tack or piece of tape can be attached to the carpet so the ideal spot can
be easily relocated when the speakers (or chair) are moved for cleaning, etc..
The entire placement procedure may seem like a great deal of work, but is
necessary in the setup of any high quality system. The time and effort
expended should be necessary only once, but will repay the owner with
countless hours of musical enjoyment.