I have not heard of the theory of two sweet spots before.
Hey Larry, I had a whole thread on this some time ago.
http://www.audiocircle.com/index.php?topic=3534Sweet spots can be enjoyed at various mid points "exactly" between the speakers that offer a balanced sonic convergence between them.
The only thing that will vary is the perceived width of the soundstage, and the frequency response of the presentation depending on the "On" or "Off" axis response.
Moving more forward will certainly move the speakers wider apart in relation to your ears and present a wider presentation perception.
I sometimes marvel at just how close you can move between the speakers (at least mine) and still get a precision and detailed center image and full stage!!
Generally, directly "on axis", will produce the best pinpoint imaging and detail, while moving further "off axis" forwards or backwards, will soften the presentation.
I like them all, but my favorite is certainly the precisely converged "on axis" position when seriously listening.
While VMPS speakers of course are tuneable, some might not like exactly "on axis" with other more conventional speakers since it sometimes can be more harsh and aggressive, with no way to tame it except to listen with them a little "off"
So in essense, we could generally say that with most good speaker systems that there is actually a "sweet line" that runs midline between the speakers where you could mover forward or backwards along that line and still be in a pretty good sweet spot.